WO2015058627A1 - 确定路径计算单元的方法及通信设备 - Google Patents

确定路径计算单元的方法及通信设备 Download PDF

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Publication number
WO2015058627A1
WO2015058627A1 PCT/CN2014/088445 CN2014088445W WO2015058627A1 WO 2015058627 A1 WO2015058627 A1 WO 2015058627A1 CN 2014088445 W CN2014088445 W CN 2014088445W WO 2015058627 A1 WO2015058627 A1 WO 2015058627A1
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Prior art keywords
pce
tcp
port
tls
pcep
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PCT/CN2014/088445
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English (en)
French (fr)
Inventor
管红光
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华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP14856765.4A priority Critical patent/EP3046293B1/en
Priority to EP19178952.8A priority patent/EP3637697A1/en
Publication of WO2015058627A1 publication Critical patent/WO2015058627A1/zh
Priority to US15/134,115 priority patent/US10110581B2/en
Priority to US16/154,297 priority patent/US11128611B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L63/00—Network architectures or network communication protocols for network security
    • H04L63/08—Network architectures or network communication protocols for network security for authentication of entities
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/42—Centralised routing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L63/00—Network architectures or network communication protocols for network security
    • H04L63/16—Implementing security features at a particular protocol layer
    • H04L63/166—Implementing security features at a particular protocol layer at the transport layer
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L63/00—Network architectures or network communication protocols for network security
    • H04L63/20—Network architectures or network communication protocols for network security for managing network security; network security policies in general
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/02—Topology update or discovery
    • H04L45/04—Interdomain routing, e.g. hierarchical routing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/12—Shortest path evaluation
    • H04L45/126—Shortest path evaluation minimising geographical or physical path length

Definitions

  • the present invention relates to the field of communications, and in particular, to a path computation element (PCE) method and a communication device.
  • PCE path computation element
  • PCE is a functional entity in the network that is responsible for path computation. It can be a stand-alone network device or a device or application on a network device.
  • the PCE calculates the client according to the path based on the known network topology and constraints.
  • the client, PCC for short, computes a path that satisfies the constraint.
  • a path calculation request is submitted and a path calculation result is obtained through a PCE communication protocol (PCEP) communication.
  • PCEP PCE communication protocol
  • the PCC first obtains the location of the PCE, the range of path calculation, the neighboring PCE, and the path calculation capability through the PCE discovery mechanism to select a PCE submission path calculation request that meets the requirements.
  • a transmission control protocol (TCP) connection is usually established between the PCC and the PCE, and then a PCEP session is established based on the TCP connection, that is, PCEP over TCP.
  • the message-digest algorithm 5 (MD5) option can be used; but with the development of the network technology, the TCP authentication configuration option (authority option, referred to as AO) Instead of TCP MD5, there is also a transport layer security (TLS) encryption protocol that provides confidentiality and data integrity. .
  • TLS transport layer security
  • the present invention provides a method for determining a PCE and a communication device for solving the problem of how to effectively establish a PCEP session.
  • an embodiment of the present invention provides a method for determining a path calculation unit, including:
  • the path calculation client PCC receives at least one route advertisement message, where the route advertisement message includes location information and transmission capability information of the path calculation unit PCE;
  • the transmission capability information of the PCE includes a first flag bit, a second flag bit, and a third flag bit, where the first flag bit is used to indicate whether the PCE supports a transmission control protocol TCP message digest algorithm fifth version MD5
  • the second flag is used to indicate whether the PCE supports the TCP authentication configuration option AO
  • the third flag is used to indicate whether the PCE supports the transport layer security TLS;
  • the route advertisement message further includes port information of the PCE, where the port information includes a port type and a port number;
  • the port type includes: a TCP-based path calculation protocol PCEP port, a TLS-based PCEP port; or,
  • the port types include: PCEP port based on TCP MD5 option, PCEP port based on TCP AO, and PCEP port based on TLS.
  • the predetermined selection policy includes:
  • the PCE supporting TLS is selected for path calculation.
  • the predetermined selection policy includes:
  • the PCE supporting TCP AO is preferentially selected for path calculation.
  • the PCE supporting TCP MD5 is selected for path calculation.
  • the PCE for path calculation is selected according to security requirements, including: transport layer security, sensitive data security, transport layer and sensitive data security; or
  • a PCE supporting TCP AO is preferentially selected for path calculation, and neither PCE is used.
  • a PCE supporting TCP MD5 for path calculation; or
  • a PCE for path calculation is selected according to the security requirement, combined with the priority of the PCE or the load information of the PCE or the preference of the PCC, and the security requirements include: Layer security, sensitive data security, transport layer and sensitive data security.
  • the route advertisement message includes an internal gateway protocol IGP route advertisement Message, Border Gateway Protocol BGP Route Advertisement message.
  • an embodiment of the present invention provides a communications device, including:
  • a receiving unit configured to receive at least one route advertisement message, where the route advertisement message includes location information and transmission capability information of the path calculation unit PCE;
  • the transmission capability information of the PCE includes a first flag bit, a second flag bit, and a a third flag bit, wherein the first flag bit is used to indicate whether the PCE supports a transmission control protocol TCP message digest algorithm version 5 MD5 option; Instructing whether the PCE supports the TCP authentication configuration option AO; the third flag is used to indicate whether the PCE supports the transport layer security TLS;
  • a determining unit configured to determine, according to the preset selection policy and the transmission capability information of the PCE in the at least one route advertisement message, the PCE used for the path calculation.
  • the route advertisement message further includes port information of the PCE, where the port information includes a port type and a port number;
  • the port type includes: a TCP-based path calculation protocol PCEP port, a TLS-based PCEP port; or,
  • the port types include: PCEP port based on TCP MD5 option, PCEP port based on TCP AO, and PCEP port based on TLS.
  • the predetermined selection policy includes:
  • the PCE supporting TLS is selected for path calculation.
  • the predetermined selection policy includes:
  • the PCE supporting TCP AO is preferentially selected for path calculation.
  • the PCE supporting TCP MD5 is selected for path calculation.
  • the PCE for path calculation is selected according to security requirements, including: transport layer security, sensitive data security, transport layer and sensitive data security; or
  • a PCE supporting TCP AO is preferentially selected for path calculation, and neither PCE is used.
  • a PCE supporting TCP MD5 for path calculation; or
  • a PCE for path calculation is selected according to the security requirement, combined with the priority of the PCE or the load information of the PCE or the preference of the PCC, and the security requirements include: Layer security, sensitive data security, transport layer and sensitive data security
  • an embodiment of the present invention provides a communications device, including:
  • a receiving unit configured to receive at least one internal gateway protocol IGP route advertisement message from the AS domain of the autonomous system, where the IGP route advertisement message includes location information and transmission capability information of the path calculation unit PCE; and the transmission capability information of the PCE includes a first flag bit, a second flag bit, and a third flag bit, wherein the first flag bit is used to indicate whether the PCE supports a transmission control protocol TCP message digest algorithm version 5 MD5 option; the second flag bit Determining whether the PCE supports the TCP authentication configuration option AO; the third flag bit is used to indicate whether the PCE supports the transport layer security TLS;
  • a generating unit configured to generate a border gateway protocol BGP route advertisement message according to the at least one IGP route advertisement message, where the BGP route advertisement message includes location information and transmission capability information of the PCE in the at least one IGP route advertisement message;
  • a sending unit configured to send the BGP route advertisement message to an AS domain other than the AS domain.
  • the IGP route advertisement message further includes port information of the PCE, where the port information includes a port type and a port number, and the port type includes: a path based on the TCP Calculating a protocol PCEP port, a TLS-based PCEP port; or, the port type includes: a PCEP port based on the fifth message MD5 option of the TCP message digest algorithm, a PC AO-based PCEP port, and a TLS-based PCEP port;
  • the BGP route advertisement message further includes the at least one IGP route advertisement message Port information in the PCE.
  • an embodiment of the present invention provides a communications device, including:
  • a generating unit configured to generate an internal gateway protocol IGP route advertisement message, where the IGP route advertisement message includes location information and transmission capability information of the path calculation unit PCE; the transmission capability information of the PCE includes a first flag bit, and the second flag And a third flag bit, wherein the first flag bit is used to indicate whether the PCE supports a Transmission Control Protocol (TCP) message digest algorithm version 5 MD5 option; the second flag bit is used to indicate whether the PCE supports TCP authentication configuration option AO; the third flag bit is used to indicate whether the PCE supports transport layer security TLS;
  • TCP Transmission Control Protocol
  • a sending unit configured to send the IGP route advertisement message to a domain where the communication device is located.
  • the IGP route advertisement message further includes port information of the PCE, where the port information includes a port type and a port number;
  • the port type includes: a TCP-based path calculation protocol PCEP port, a TLS-based PCEP port; or,
  • the port types include: a PCEP port based on the MD5 option of the TCP message digest algorithm, a PCEP port based on TCP AO, and a PCEP port based on TLS.
  • the PCC receives the route advertisement message carrying the location information and the transmission capability information of the PCE, and selects the PCC transmission capability according to the transmission capability information of the PCE and the preset selection policy.
  • the PCE is used for path calculation, which can establish a PCEP session more effectively, thereby improving the efficiency and success rate of the PCC submitting the path calculation request and obtaining the path calculation result.
  • FIG. 1 is a flowchart of a method for advertising transmission capability according to an embodiment of the present invention
  • 2a is a schematic diagram of a format of an OSPF PCED TLV or an IS-IS PCED sub-TLV according to an embodiment of the present invention
  • 2b is a schematic diagram of a format of a sub-TLV carrying port information according to an embodiment of the present disclosure
  • FIG. 3 is a flowchart of another method for advertising transmission capability according to an embodiment of the present invention.
  • FIG. 4 is a flowchart of a method for determining a path calculation unit according to an embodiment of the present invention
  • FIG. 5 is a flowchart of a method for advertising a transmission capability and determining a path calculation unit according to an embodiment of the present invention
  • FIG. 6 is a flowchart of another method for advertising a transmission capability and determining a path calculation unit according to an embodiment of the present invention
  • FIG. 7 is a flowchart of still another method for advertising transmission capability and determining a path calculation unit according to an embodiment of the present invention.
  • FIG. 8 is a structural block diagram of a communication device according to an embodiment of the present invention.
  • FIG. 9 is a structural block diagram of another communication device according to an embodiment of the present invention.
  • FIG. 10 is a structural block diagram of still another communication device according to an embodiment of the present invention.
  • FIG. 11 is a schematic structural diagram of a communication device according to an embodiment of the present disclosure.
  • FIG. 12 is a schematic structural diagram of another communication device according to an embodiment of the present disclosure.
  • FIG. 13 is a schematic structural diagram of still another communication device according to an embodiment of the present invention.
  • the PCC and PCE may fail to establish a PCEP session, and the PCC cannot submit to the PCE.
  • the path calculates the request and gets the path calculation result.
  • the PCC needs to wait for a new route advertisement message, such as OSPF link state advertisement (LSA), to obtain a PCE that satisfies its own path calculation request and supports TLS, in order to successfully establish a PCEP session, and then submit a path calculation request and obtain Path calculation result.
  • LSA OSPF link state advertisement
  • the PCC may have to go through multiple failures to successfully establish a PCEP session to obtain path calculation results, thus reducing the efficiency of path computation in the network.
  • the present invention provides a technical solution for transmitting a route advertisement message carrying a PCE transmission capability to a PCC, so that the PCC determines a PCE for path calculation according to the PCE transmission capability in the route advertisement message.
  • an embodiment of the present invention provides a method for advertising transmission capability, including:
  • the communication device generates an IGP route advertisement message, where the IGP route advertisement message includes location information and transmission capability information of the first path calculation unit PCE.
  • the transmission capability information of the first PCE includes a first flag bit, a second flag bit, and a third flag bit.
  • the first flag bit is used to indicate whether the first PCE supports a transmission control protocol TCP message digest algorithm.
  • the fifth version of the MD5 option (English: PCEP over TCP MD5); the second flag is used to indicate whether the first PCE supports the TCP authentication configuration option AO (English: PCEP over TCP AO); the third flag bit It is used to indicate whether the first PCE supports Transport Layer Security TLS (English: PCEP over TLS).
  • the transmission capability information of the first PCE further includes a fourth flag bit, where the fourth flag bit is used to indicate whether the first PCE supports TLS and TCP AO.
  • the route advertisement message may further include port information of the first PCE, where the port information includes a port type and a port number.
  • the port types include: TCP-based PCEP (English: PCEP over TCP) port, TLS-based PCEP (English: PCEP over TLS) port.
  • the port type includes: PCEP based on the TCP MD5 option (English: PCEP over TCP MD5) Port, TCPEP-based PCEP (English: PCEP over TCP AO) port, TLS-based PCEP (English: PCEP over TLS) port; further optionally, if the first PCE's transmission capability information further includes a fourth flag Bits, correspondingly the port types include: PCEP (English: PCEP over TLS and TCP AO) ports based on TLS and TCP AO.
  • the communication device is an IGP router, and the domain of the communication device is an IGP domain; specifically, the IGP includes OSPF, IS-IS; correspondingly, the communication device is an OSPF router, where the communication device is located The domain is an OSPF domain, and the IGP route advertisement message is an OSPF LSA; or the communication device is an IS-IS router, the communication device is in an IS-IS domain, and the IGP route advertisement message is an IS-IS LSA. .
  • PCC and PCE When PCC and PCE are in a routing domain, they support the same internal gateway protocol (IGP), such as open shortest path first (OSPF) protocol or intermediate system to intermediate system (intermediate system).
  • IGP internal gateway protocol
  • OSPF open shortest path first
  • IS-IS intermediate system to intermediate system
  • the dynamic discovery of the PCE can be implemented through the OSPF protocol or the IS-IS protocol.
  • OSPF The OSPF flooding mechanism is used to transmit PCE information through OSPF control messages, such as link state advertisement LSAs, to flood the entire PCE.
  • OSPF control messages such as link state advertisement LSAs
  • Members in the OSPF domain to notify PCE related information, including the location of the PCE, the range of calculation of the PCE path, the neighboring PCE, the communication capability, and the path calculation capability.
  • the IS-IS protocol is used to notify PCE related information, including PCE, by using PCED sub-TLVs (sub-TLVs) to pass PCE information through IS-IS control messages, such as LSAs, to the entire IS-IS domain.
  • PCE related information including PCE
  • sub-TLVs PCED sub-TLVs
  • LSAs IS-IS control messages
  • the calculation range of the PCE path may include the IS-IS domain, the IS-IS domain, and the autonomous system. (autonomous system, referred to as AS), across the network layer, and so on.
  • AS autonomous system
  • the location information of the first PCE such as the Internet Protocol version 4 (IPv4) address or the Internet Protocol version 6, IPv6 address, may be carried in the PCED TLV of the OSPF protocol. Or the PCE address (PCE-ADDRESS) sub-TLV in the PCED sub-TLV of the IS-IS protocol.
  • the transmission capability information of the PCE may be extended by the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol, and three currently unused ones are defined in the PCE capability flag (PCE-CAP-FLAGS) sub-TLV.
  • the flag bit as the first flag bit, the second flag bit, and the third flag bit, respectively, are used to indicate whether the first PCE supports the TCP MD5 option, whether the first PCE supports TCP AO, the first Whether the PCE supports TLS; further, a fourth flag bit may also be defined to indicate whether the first PCE supports TLS and TCP AO.
  • the format of the PCED sub-TLV of the PCED TLV or IS-IS protocol of OSPF can be as shown in Figure 2a.
  • the correspondence between the four flag bits extended in the PCE-ADDRESS sub-TLV and the PCE capability description in FIG. 2a can be as follows:
  • TCP MD5 PCEP over TCP MD5
  • TCP AO PCEP over TCP AO
  • TLS PCEP over TLS
  • TLS and TCP AO are supported (PCEP over TLS and TCP AO)
  • the PCE transmission capability can be advertised, so that the PCC can select the PCE that matches its own transmission capability, improve the PCC submission path calculation request, and obtain the path calculation. The efficiency and success rate of the results.
  • PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol may be extended.
  • a sub-TLV carrying the port information of the first PCE is defined, and the format can be as shown in FIG. 2b. There are two implementations that carry the port information of the first PCE:
  • One is to define port information of two sub-TLVs carrying a PCE, where one sub-TLV carries a TCP-based PCEP (English: PCEP over TCP) port, and one sub-TLV carries a TLS-based PCEP (English: PCEP over TLS) port.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the transmission capability information of the first PCE further includes a fourth flag bit, a sub-TLV may be further defined for carrying a PCEP over TCP and TCP AO based port (English: PCEP over TLS and TCP AO).
  • the PCEP over TCP MD5 port sub-TLV is carried in the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol;
  • the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol carries the sub-TLV of the PCEP over TCP AO port;
  • the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol carries the sub-TLV of the PCEP over TLS port;
  • the sub-TLV of the PCEP over TLS and TCP AO ports is carried in the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol.
  • the first flag in the PCE-CAP-FLAGS sub-TLV indicates that the PCE supports the TCP MD5 option, or the second flag indicates that the PCE supports TCP AO, or the first flag indicates that the PCE supports the TCP MD5 option and The second flag indicates that the PCE supports the TCP AO, and carries the PCEP over TCP port sub-TLV in the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol;
  • the third flag in the PCE-CAP-FLAGS sub-TLV indicates that the PCE supports TLS
  • the fourth flag indicates that the PCE supports TLS and TCP AO
  • the third flag indicates that the PCE supports TLS and the fourth flag indicates PCE Supports TLS and TCP AO
  • the method may further include: the communication device receiving registration information of the first PCE, where the registration information includes a transmission capability of the first PCE.
  • the registration information also includes a range of PCE path calculations, neighboring PCEs, communication capabilities, and path computation capabilities.
  • the route advertisement message may further include location information and transmission capability information of the second PCE; optionally, port information of the second PCE.
  • the method may further include: the communication device receiving registration information of the second PCE, where the registration information includes a transmission capability of the second PCE.
  • the method for advertising the transmission capability extends the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol, and defines a flag bit to indicate the transmission capability of the PCE, so that the method can be implemented based on the OSPF protocol or the IS-IS protocol.
  • the notification of the PCE transmission capability enables the PCC to select a PCE that matches its own transmission capability, ensuring that a PCEP session is effectively established between the PCC and the PCE, thereby improving the efficiency and success rate of path calculation between the PCC and the PCE; further, by defining a new The sub-TLV carries the port information corresponding to the transmission capability, so that when the PCC does not know the port used by the PCE to establish a PCEP session, It can be obtained directly from the OSPF LSA or IS-IS LSA, which further ensures that the PCEP session is effectively established between the PCC and the PCE.
  • the embodiment of the present invention provides another method for advertising transmission capability, including:
  • a border gateway protocol (BGP) router receives at least one IGP route advertisement message from an AS domain of the autonomous system, where the IGP route advertisement message includes location information and transmission capability information of the path calculation unit PCE.
  • BGP border gateway protocol
  • the transmission capability information of the PCE includes a first flag bit, a second flag bit, and a third flag bit, where the first flag bit is used to indicate whether the PCE supports a transmission control protocol TCP digest algorithm 5 option;
  • the second flag is used to indicate whether the PCE supports the TCP authentication configuration option AO;
  • the third flag is used to indicate whether the PCE supports the transport layer security TLS;
  • the transmission capability information of the PCE further includes a fourth flag, configured to indicate whether the PCE supports TLS and TCP AO;
  • the IGP route advertisement message is an OSPF LSA or an IS-IS LSA.
  • the BGP router may be a BGP speaker (English: speaker).
  • three currently unused flag bits may be defined in the PCED TLV of the OSPF protocol or the PCE-CAP-FLAGS sub-TLV of the PCED sub-TLV of the IS-IS protocol, as the first flag bit,
  • the second flag bit and the third flag bit are respectively used to indicate whether the first PCE supports the TCP MD5 option, whether the first PCE supports the TCP AO, whether the first PCE supports TLS, and further, the first The fourth flag is used to indicate whether the first PCE supports TLS and TCP AO.
  • the at least one IGP route advertisement message Generate, according to the at least one IGP route advertisement message, a border gateway protocol BGP route advertisement message, where the BGP route advertisement message includes location information and transmission capability information of the PCE in the at least one IGP route advertisement message.
  • the BGP router receives two IGP route advertisement messages: the first IGP route And the second IGP route advertisement message includes the location information and the transmission capability information of the first PCE, where the second route advertisement message includes the location information and the transmission capability information of the second PCE, the first IGP The route advertisement message and the second IGP route advertisement message are from an AS domain; the BGP router generates the BGP route advertisement message according to the first route advertisement message and the second route advertisement message, where the BGP route advertisement message The location information and transmission capability information of the first PCE, and the location information and transmission capability information of the second PCE are included.
  • a BGP router may generate a BGP route advertisement message according to only one IGP route advertisement message, or generate a BGP route advertisement message according to multiple IGP route advertisement messages received by an AS domain, and route multiple IGP routes.
  • the location information and transmission capability information of each PCE carried in the advertisement message is sent to other AS domains through a BGP route advertisement message.
  • the BGP router further includes: checking whether the IGP route advertisement message includes the transmission capability information of the PCE; if the transmission capability information of the PCE is included, generating the PCE The BGP route advertisement message of the location information and the transmission capability information; if the transmission capability information of the PCE is not included, the processing is performed according to the existing standard specifications.
  • the BGP protocol can be extended.
  • the PCE-ADDRESS sub-TLV and the PCE-CAP-FLAGS sub-TLV are defined and carried in the BGP.
  • the route advertisement message The format of the PCE-ADDRESS sub-TLV and the PCE-CAP-FLAGS sub-TLV may be the same as the PCED TLV of the extended OSPF protocol or the PCED sub-TLV of the IS-IS protocol, as shown in FIG. 2a.
  • the transmission capability information of the PCE may also be extended by the capability parameter of the BGP protocol (English: capability optional parameter), and the capability code currently used is not used to identify the transmission capability of the PCE; specifically, three capabilities are defined. Encoding, which is used to identify whether the TCP MD5 option is supported, whether TCP AO is supported, and whether TLS is supported. Further, a capability code can be defined to identify whether TLS and TCP AO are supported.
  • the IGP route advertisement message may further include port information of the PCE, where the port information includes a port type and a port number; and the port type includes: a TCP-based PCEP (English) Text: PCEP over TCP) port, TLS-based PCEP (English: PCEP over TLS) port.
  • the port type includes: PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, PCEP over TLS based on TLS (English: PCEP over TLS) Port; further, it may also include a PCEP (English: PCEP over TLS and TCP AO) port based on TLS and TCP AO.
  • the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol may be extended, and the sub-TLV carrying the port information of the first PCE may be defined, and the format may be as shown in FIG. 2b. The method shown in FIG. 1 is not repeated here.
  • the BGP route advertisement message may further include port information of the PCE.
  • the BGP protocol can be extended.
  • the sub-TLV carrying the port information of the PCE is defined in the NLRI, and the format can be as shown in FIG. 2b. Similar to the extension of OSPF or IS-IS, there are two implementations that carry port information of the PCE:
  • One is to define port information of two sub-TLVs carrying a PCE, where one sub-TLV carries a TCP-based PCEP (English: PCEP over TCP) port, and one sub-TLV carries a TLS-based PCEP (English: PCEP over TLS) port.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the transmission capability information of the first PCE further includes a fourth flag bit, a sub-TLV may be further defined for carrying a PCEP over TCP and TCP AO based port (English: PCEP over TLS and TCP AO).
  • the at least one IGP route advertisement message is from a first AS, where the BGP router is located on the first AS and the second AS boundary, sending the BGP route advertisement message to the a second AS, to notify a member of the second AS of the transmission capability of the first PCE.
  • the IGP route advertisement message may include only location information and transmission capability information of one PCE, and may also include location information and transmission capability information of multiple PCEs.
  • the BGP route advertisement message includes location information and transmission capability information of multiple PCEs in the IGP route advertisement message.
  • the BGP router realizes the notification of the PCE transmission capability between the ASs through the extended BGP protocol, and can ensure that the PCC session is effectively established between the PC and the PCE, thereby improving the path calculation between the PCC and the PCE. Efficiency and success rate.
  • an embodiment of the present invention provides a method for determining a path calculation unit, including:
  • the PCC receives at least one route advertisement message, where the route advertisement message includes location information and transmission capability information of the path calculation unit PCE.
  • the transmission capability information of the PCE includes a first flag bit, a second flag bit, and a third flag bit, wherein the first flag bit is used to indicate whether the PCE supports a TCP MD5 option; the second flag bit is used by Indicates whether the PCE supports TCP AO; the third flag is used to indicate whether the PCE supports TLS.
  • the flag bit when the flag bit is 0, it indicates that it is not supported; when the flag bit is 1, it indicates support; for example, in the route advertisement message, the first flag bit is 1, indicating that the PCE supports TCP MD5; The second flag bit is 0, indicating that the PCE does not support TCP AO; the third flag bit is 1, indicating that the PCE supports TLS.
  • the second flag indicates that the PCE supports TCP AO
  • the third flag indicates that the PCE supports TLS
  • the second flag bit and the third flag bit are combined.
  • the PCE is instructed to support TLS and TCP AO (English: PCEP over TLS and TCP AO).
  • the transmission capability information of the PCE further includes a fourth flag bit, where the fourth flag bit is used to indicate whether the PCE supports TLS and TCP AO.
  • the route advertisement message further includes port information of the PCE, where the port information includes a port type and a port number.
  • the port types include: a TCP-based path calculation protocol PCEP port, a TLS-based PCEP port.
  • the port type includes: a PCEP port based on the TCP digest algorithm 5 option, a TCP AO-based PCEP port, a TLS-based PCEP port; and further optionally, if the PCE transmission capability information further includes a fourth flag bit
  • the port types include: PCEP ports based on TLS and TCP AO.
  • the route advertisement message may be an IGP route advertisement message (refer to the method shown in FIG. 1 of the present invention) or a BGP route advertisement message (refer to the method shown in FIG. 3 of the present invention). among them,
  • the IGP route advertisement message may be an OSPF LSA or an IS-IS LSA.
  • the location information of the PCE such as an IPv4 address or an IPv6 address, may be carried in the PCED TLV of the OSPF LSA or the PCED sub of the IS-IS LSA.
  • the transmission capability information of the PCE can be extended by the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol, and three are defined in the PCE-CAP-FLAGS sub-TLV
  • the flag bits that are not currently used are respectively the first flag bit, the second flag bit, and the third flag bit described above; further, the fourth flag bit may also be defined.
  • PCED sub-TLV of the PCED TLV or IS-IS protocol of OSPF can be as shown in Figure 2a.
  • the correspondence between the four flag bits extended in the PCE-ADDRESS sub-TLV in FIG. 2a and the PCE capability description may be as follows:
  • TCP MD5 PCEP over TCP MD5
  • TCP AO PCEP over TCP AO
  • TLS PCEP over TLS
  • TLS and TCP AO are supported (PCEP over TLS and TCP AO)
  • flag bits 12, 13, 14 and 15 are defined as an example, and the capability descriptions corresponding to the above-mentioned respective flag bits are only examples, and do not constitute a limitation of the present invention.
  • the PCE capability discovery of the OSPF protocol or the IS-IS protocol is extended to implement the PCE. Announcement of transmission capabilities.
  • the PCC receives the route advertisement message carrying the PCE transmission capability information, and selects the PCE that matches its own transmission capability, so as to ensure that the PCEP session is effectively established between the PCC and the PCE, thereby improving the efficiency of submitting the path calculation request and obtaining the path calculation result between the PCC and the PCE. And success rate.
  • the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol may be extended to define a sub-TLV carrying the port information of the PCE, and the format may be as shown in FIG. 2b.
  • the format can be as shown in Figure 2b. There are two implementations that carry the port information of the first PCE:
  • One is to define port information of two sub-TLVs carrying a PCE, where one sub-TLV carries a TCP-based PCEP (English: PCEP over TCP) port, and one sub-TLV carries a TLS-based PCEP (English: PCEP over TLS) port.
  • the four-flag bit supports TLS and sub-TLVs that support TLS and TCP AO sharing PCEP over TLS ports.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the transmission capability information of the PCE further includes a fourth flag bit, a sub-TLV may be further defined for carrying a PCEP over TCP and TCP AO based port (English: PCEP over TLS and TCP AO).
  • the PCEP over TCP MD5 port sub-TLV is carried in the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol;
  • the second flag in the PCE-CAP-FLAGS sub-TLV indicates that the PCE supports TCP AO, in OSPF a PCED TLV of the protocol or a sub-TLV carrying a PCEP over TCP AO port in a PCED sub-TLV of the IS-IS protocol;
  • the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol carries the sub-TLV of the PCEP over TLS port;
  • the PCEP over TLS and TCP AO ports are carried in the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol. sub-TLV.
  • the first flag in the PCE-CAP-FLAGS sub-TLV indicates that the PCE supports the TCP MD5 option, or the second flag indicates that the PCE supports TCP AO, or the first flag indicates that the PCE supports the TCP MD5 option and The second flag indicates that the PCE supports the TCP AO, and carries the PCEP over TCP port sub-TLV in the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol;
  • the third flag in the PCE-CAP-FLAGS sub-TLV indicates that the PCE supports TLS
  • the fourth flag indicates that the PCE supports TLS and TCP AO
  • the third flag indicates that the PCE supports TLS and the fourth flag indicates PCE Supports TLS and TCP AO
  • the BGP route advertisement message includes the location information and the transmission capability information of the PCE.
  • the BGP protocol can be extended.
  • the PCE-ADDRESS sub-TLV and the PCE are defined.
  • the CAP-FLAGS sub-TLV is carried in the BGP route advertisement message, where the PCE-ADDRESS sub-TLV is used to carry the location information of the PCE, and the PCE-CAP-FLAGS sub-TLV is used to carry the transmission capability information of the PCE.
  • the specific format may be the PCED TLV of the extended OSPF protocol or the PCED sub-TLV of the IS-IS protocol, as shown in Figure 2a.
  • the BGP route advertisement message may further include port information of the PCE, where the port information includes a port type and a port number; and corresponding to the IGP route advertisement message, the end
  • the port type includes: a PCEP over TCP port and a PCEP over TLS port; or the port type includes: a PCEP over TCP MD5 port, a base PCEP over TCP AO port, and a PCEP over TLS port; and further, may include PCEP over TLS and TCP AO port.
  • the BGP protocol can be extended, for example, a sub-TLV carrying the port information of the PCE in the NLRI, and the format can be as shown in FIG. 2b.
  • the port information of the PCE may be carried in two implementation manners:
  • the four-flag bit supports TLS and sub-TLVs that support TLS and TCP AO sharing PCEP over TLS ports.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the transmission capability information of the PCE further includes a fourth flag bit, a sub-TLV may be further defined for carrying a PCEP over TCP and TCP AO based port (English: PCEP over TLS and TCP AO).
  • the PCC determines, according to the preset selection policy and the transmission capability information of the PCE in the at least one route advertisement message, the PCE used for path calculation.
  • the preset selection strategy includes:
  • a PCE having the transmission capability supported by the PCC is selected for path calculation.
  • the PCC supports TCP MD5.
  • the PCE supports TCP MD5 and also supports TLS. If the PCE has the transmission capability supported by the PCC, the policy and the selection are selected according to presets. The transmission capability information of the first PCE is determined, and the PCC determines that the PCE is used for path calculation.
  • the preset selection policy may be: combining a PCE priority or a PCE load information or the PCC preference, and selecting a PCE having the transmission capability supported by the PCC for path calculation; specifically, Taking the priority of the PCE as an example, the preset selection policy includes: if only one PCE has the transmission capability supported by the PCC, the PCE is selected for path calculation; if multiple PCEs are supported by the PCC The transmission capability selects a PCE with a higher priority among the plurality of PCEs for path calculation.
  • the route advertisement message may include only location information and transmission capability information of one PCE; and may include location information and transmission capability information of multiple PCEs.
  • the PCC may determine the PCE for path calculation according to the transmission capability information of one or more PCEs in one route advertisement message, or according to the transmission capability information of all PCEs in the multiple route advertisement messages.
  • the PCC receives the first route advertisement message and the second route advertisement message, where the first route advertisement message includes location information and transmission capability information of the first PCE, location information and transmission capability information of the second PCE, The second route advertisement message includes location information and transmission capability information of the third PCE.
  • PCC1 supports TCP MD5.
  • the first PCE supports TCP MD5 and also supports TLS.
  • the second PCE Supporting TCP MD5, also supporting TCP AO;
  • the third PCE supports TLS and TCP AO.
  • the first PCE and The second PCE has the transmission capability supported by the PCC1
  • the third PCE does not have the transmission capability supported by the PCC1.
  • the PCC1 determines that the first PCE or the second PCE is used for path calculation, and may also determine the The first PCE and the second PCE are used for path computation without selecting the third PCE for path computation.
  • the PCC1 further determines, according to the priority of the first PCE and the priority of the second PCE, the second PCE with a higher priority for path calculation.
  • the preset selection policy includes: if the PCC supports both the TCP AO and the TCP MD5, the PCE supporting the TCP AO is preferentially selected for the path calculation, and if any PCE does not support the TCP AO, the selection is performed.
  • PCE supporting TCP MD5 is used for path calculation.
  • the preset selection policy includes: if the PCC supports both TCP AO and TCP MD5, the PCE priority is combined.
  • Level or PCE load information or the PCC preference preferentially select a PCE that supports TCP AO for path calculation, combined with PCE priority or PCE load information if any PCE does not support TCP AO
  • a PCE supporting TCP MD5 is selected for path calculation.
  • the preset selection policy includes: if the PCC supports both TCP AO and TCP MD5, if multiple PCEs support TCP AO, select a PCE with a higher priority for path calculation; If only one PCE supports TCP AO, it is determined that the PCE is used for path calculation; if any PCE does not support TCP AO, if multiple PCEs support TCP MD5, select a PCE with higher priority for path calculation, if Only one PCE supports TCP MD5, which is determined to be used for path computation.
  • PCC2 supports TCP AO and supports TCP MD5.
  • the first PCE supports TCP MD5 and also supports TLS.
  • the second PCE supports TCP MD5 and also supports TCP AO;
  • the third PCE supports TLS and TCP AO.
  • PCC2 determines that the second PCE or the third PCE is used for path calculation, and may also determine that the second PCE and the third PCE are used for path calculation without The first PCE is selected for path computation.
  • the PCC2 further determines, according to the priority of the second PCE and the priority of the third PCE, that the second PCE with a higher priority is used for path calculation.
  • the preset selection policy includes: if the PCC supports TLS and TCP AO, determining a PCE for path calculation according to security requirements; the security requirements include: transport layer security, sensitive data security, and transport layer And sensitive data security.
  • the preset selection policy specifically includes: if the PCC supports TLS and TCP AO, when the security requirement is the transport layer and the sensitive data security, select a PCE supporting TLS and TCP AO for path calculation; when security Support for TCP AO when the sexual requirement is the transport layer The PCE is used for path computation; when the security requirement is sensitive data security, a PCE supporting TLS is selected for path computation.
  • a PCE is determined for path calculation
  • the preset selection policy includes: if the PCC supports TLS and TCP AO, according to security requirements, combined with the priority of the PCE or Determining a PCE for path calculation by using load information of the PCE or the preference of the PCC; specifically, the preset selection policy includes: if the PCC supports TLS and TCP AO, when multiple PCEs meet the security When required, the PCE with higher priority may be selected for path calculation according to the priority of the multiple PCEs or the load information of the multiple PCEs or the preference of the PCC; when only one PCE satisfies the security When the demand is met, it is determined that the PCE is used for path calculation.
  • scenario 3 PCC3 supports TLS and TCP AO.
  • the first PCE supports TCP MD5 and also supports TLS.
  • the transmission capability information of the second PCE supports TCP MD5 and also supports TCP AO;
  • the third PCE supports TLS and TCP AO.
  • the security requirement is the security of the transport layer and the sensitive data
  • the transmission capability information of the second PCE is the transmission capability information of the third PCE
  • the third PCE supports TLS and TCP AO, then PCC3 determines that the priority of the third PCE is used for path computation, and the first PCE or the two PCEs are not selected for path computation.
  • the PCC3 determines that the first PCE or the third PCE is used for path computation; it may also be determined that the first PCE and the third PCE are used for path computation, and The two PCEs are not selected for path computation.
  • the PCC3 further determines, according to the priority of the first PCE and the priority of the third PCE, that the first PCE with a higher priority is used for path calculation.
  • the PCC3 determines that the second PCE or the third PCE is used for path calculation; and the second PCE and the third PCE may also be determined to be used for The path is calculated without selecting the first PCE for path calculation.
  • the PCC3 further determines, according to the priority of the second PCE and the priority of the third PCE, that the second PCE with a higher priority is used for path calculation.
  • the security requirement may also be set according to the preference of the PCC, for example, the transport layer and the sensitive data security, the transport layer security is prioritized over the sensitive data security, and the transport layer security is prioritized over the sensitive data security.
  • the preset selection policy includes: if the PCC supports TLS and TCP AO, preferentially select a PCE supporting TLS and TCP AO for path calculation; if any PCE does not support TLS and TCP AO, The PCE supporting TCP AO is preferentially selected for path calculation; if any PCE does not support TCP AO, the PCE supporting TLS is selected for path calculation.
  • the priority information of the PCE may be carried in a PCED TLV of the OSPF protocol or a PCED sub-TLV of the IS-IS protocol.
  • the priority of the second PCE is higher than the priority of the first PCE, and the priority of the first PCE is higher than the priority of the third PCE as an example. It is not intended to limit the invention.
  • the PCE load information includes a load capacity of the PCE, a current load condition, and the like.
  • a PCE with a strong load capacity and a small current load can be selected for path calculation.
  • the preset selection policy may also be combined with the local policy of the PCC.
  • the local policy is to select a PCE that supports the most transmission capability; of course, the local policy of the PCC may be statically configured or dynamically adjusted according to requirements.
  • the PCC receives a route advertisement message carrying the PCE transmission capability information, and selects and transmits according to the transmission capability and the preset selection policy of the PCE.
  • the PCE with matching capacity is used for path calculation, which can ensure the effective establishment of PCEP session between PCC and PCE, thus improving the success rate and efficiency of path calculation between PCC and PCE.
  • FIG. 5 is a flowchart of a method for advertising a transmission capability and determining a path calculation unit according to an embodiment of the present invention, including the following steps:
  • the router 1 generates a route advertisement message 1, and sends the route advertisement message 1 to the domain where the router 1 is located;
  • the route advertisement message 1 carries the PCE-ADDRESS sub-TLV and the PCE-CAP-FLAGS sub-TLV, wherein, the PCE-ADDRESS
  • the location of PCE1 in the sub-TLV, PCE-CAP-FLAGS sub-TLV indicates that PCE1 supports TLS;
  • the PCC receives the route advertisement message 1;
  • the router 2 generates the route advertisement message 2 and broadcasts in the domain.
  • the route advertisement message 2 carries the PCE-ADDRESS sub-TLV and the PCE-CAP-FLAGS sub-TLV.
  • the PCE-ADDRESS sub-TLV carries the location of the PCE2.
  • PCE-CAP-FLAGS sub-TLV indicates that PCE2 supports TCP AO;
  • the PCC receives the route advertisement message 2;
  • the router 3 generates a route advertisement message 3 and broadcasts in the domain.
  • the route advertisement message 3 carries a PCE-ADDRESS sub-TLV and a PCE-CAP-FLAGS sub-TLV.
  • the PCE-ADDRESS sub-TLV carries the location of the PCE3.
  • PCE-CAP-FLAGS sub-TLV indicates that PCE3 supports TCP MD5 and TCP AO;
  • the PCC receives the route advertisement message 3;
  • time sequence between 501-502, 503-504, and 505-506 is not limited, 505-506 may occur at 501-502, or may occur before 501-504 after 501-502; Of course, 501-502, 503-504, and 505-506 can also occur simultaneously.
  • the PCC determines, according to the transmission capability information of the PCE1, the transmission capability information of the PCE2, the transmission capability information of the PCE3, and the preset selection policy, the PCE used by the PCE1 for path calculation.
  • PCC1 After PCC1 is selected, PCC1 establishes a TLS connection with PCE1, then establishes a PCEP session, submits a path calculation request, and obtains a path calculation result.
  • FIG. 6 is a flowchart of another method for advertising a transmission capability and determining a path calculation unit according to an embodiment of the present invention, including the following steps:
  • Router 1 generates a route advertisement message 1 and broadcasts in the domain, and the route advertisement message 1 carries a PCE-ADDRESS sub-TLV and a PCE-CAP-FLAGS sub-TLV, wherein the PCE-ADDRESS sub-TLV carries the location of the PCE1, PCE-CAP-FLAGS sub-TLV indicates that PCE1 supports TCP MD5;
  • the PCC receives the route advertisement message 1;
  • the router 2 generates the route advertisement message 2 and broadcasts in the domain.
  • the route advertisement message 2 carries the PCE-ADDRESS sub-TLV and the PCE-CAP-FLAGS sub-TLV.
  • the PCE-ADDRESS sub-TLV carries the location of the PCE2.
  • PCE-CAP-FLAGS sub-TLV indicates that PCE2 supports TLS;
  • the PCC receives the route advertisement message 2;
  • the router 3 generates a route advertisement message 3 and broadcasts in the domain.
  • the route advertisement message 3 carries a PCE-ADDRESS sub-TLV and a PCE-CAP-FLAGS sub-TLV.
  • the PCE-ADDRESS sub-TLV carries the location of the PCE3.
  • PCE-CAP-FLAGS sub-TLV indicates that PCE3 supports TLS and TCP MD5;
  • the PCC receives the route advertisement message 3;
  • time sequence between 601-602, 603-604, and 605-606 is not limited, 605-606 may occur at 601-602, or may occur before 603-604 after 601-602; Of course, 601-602, 603-604, and 605-606 can also occur simultaneously.
  • the PCC determines, according to the transmission capability information of the PCE1, the transmission capability information of the PCE2, the transmission capability information of the PCE3, and the preset selection policy, the PCE used by the PCE1 for path calculation.
  • PCC supports TCP AO and TCP MD5, while PCE1, PCE2 and PCE3 do not support TCP AO; PCE1 and PCE3 both support TCP MD5, and PCE1 has higher priority than PCE3, so PCC selects PCE1 for path calculation.
  • PCC1 After PCC1 is selected, PCC1 establishes a TLS connection with PCE1, then establishes a PCEP session, submits a path calculation request, and obtains a path calculation result.
  • FIG. 7 is a flowchart of still another method for advertising transmission capability and determining a path calculation unit according to an embodiment of the present invention, including the following steps:
  • Router 1 generates a route advertisement message 1 and broadcasts in the domain.
  • the route advertisement message 1 carries a PCE-ADDRESS sub-TLV and a PCE-CAP-FLAGS sub-TLV.
  • the PCE-ADDRESS sub-TLV carries the location of the PCE1.
  • PCE-CAP-FLAGS sub-TLV indicates that PCE1 supports TCP MD5 and TLS;
  • the PCC receives the route advertisement message 1;
  • Router 2 generates a route advertisement message 2 and broadcasts in the domain.
  • the route advertisement message 2 carries a PCE-ADDRESS sub-TLV and a PCE-CAP-FLAGS sub-TLV.
  • the PCE-ADDRESS sub-TLV carries the location of the PCE2.
  • PCE-CAP-FLAGS sub-TLV indicates that PCE2 supports TCP MD5 and TCP AO;
  • the PCC receives the route advertisement message 2;
  • the router 3 generates a route advertisement message 3 and broadcasts in the domain.
  • the route advertisement message 3 carries a PCE-ADDRESS sub-TLV and a PCE-CAP-FLAGS sub-TLV.
  • the PCE-ADDRESS sub-TLV carries the location of the PCE3.
  • PCE-CAP-FLAGS sub-TLV indicates that PCE3 supports TLS and TCP AO;
  • the PCC receives the route advertisement message 3;
  • time sequence between 701-702, 703-704, and 705-706 is not limited, 705-706 may occur at 701-702, or may occur before 701-704 after 701-702; Of course, 701-702, 703-704, and 705-706 can also occur simultaneously.
  • the PCC determines the PCE used for path calculation according to the transmission capability information of the PCE1, the transmission capability information of the PCE2, the transmission capability information of the PCE3, and the preset selection policy.
  • the PCC determines that the PCE3 is used for path calculation according to the transmission capability information of the PCE1, the transmission capability information of the PCE2, the transmission capability information of the PCE3, and the preset selection policy. After PCC3 is selected by PCC, a TLS and TCP AO connection is established with PCE3, and then a PCEP session is established, that is, PCEP over TLS and TCP AO are established, a path calculation request is submitted, and a path calculation result is obtained.
  • the PCC supports TLS according to the transmission capability information of the PCE1, the transmission capability information of the PCE2, the transmission capability information of the PCE3, and the preset selection policy, and the PCC according to the priorities of the PCE1 and the PCE3. Make sure PCE1 is used for path calculation. After PCC1 is selected, PCC1 establishes a TLS connection with PCE1, and then establishes a PCEP session, that is, establishes PCEP over TLS, submits a path calculation request, and obtains a path calculation result.
  • the PCC supports TCP AO according to the transmission capability information of PCE1, the transmission capability information of PCE2, the transmission capability information of PCE3, and the preset selection policy.
  • the PCC is based on the priorities of PCE2 and PCE3. , determine PCE2 for path calculation.
  • the PCA establishes a TCP AO connection with the PCE1, and then establishes a PCEP session, that is, establishes a PCEP over TCP AO, submits a path calculation request, and obtains a path calculation result.
  • FIG. 8 is a structural block diagram of a communication device according to an embodiment of the present invention.
  • the communication device is specifically a PCC network element, and is used to implement the method shown in FIG. 4 of the present invention.
  • the method includes: a receiving unit 801 and a determining unit 802; wherein
  • the receiving unit 801 is configured to receive at least one route advertisement message, where the route advertisement message includes location information and transmission capability information of the PCE, and the transmission capability information of the PCE includes the first flag. a bit, a second flag bit, and a third flag bit, wherein the first flag bit is used to indicate whether the PCE supports a Transmission Control Protocol TCP Digest Algorithm 5 option; the second flag bit is used to indicate the first Whether the PCE supports the TCP authentication configuration option AO; the third flag is used to indicate whether the PCE supports Transport Layer Security TLS.
  • the second flag indicates that the PCE supports TCP AO
  • the third flag indicates that the PCE supports TLS
  • the second flag bit and the third flag bit are combined.
  • the PCE is instructed to support TLS and TCP AO (English: PCEP over TLS and TCP AO).
  • the transmission capability information of the PCE further includes a fourth flag bit, where the fourth flag bit is used to indicate whether the PCE supports TLS and TCP AO.
  • the flag bit when the flag bit is 0, it indicates that it is not supported; when the flag bit is 1, it indicates support; for example, in the route advertisement message, the first flag bit is 1, indicating that the PCE supports TCP MD5; The second flag bit is 0, indicating that the PCE does not support TCP AO; the third flag bit is 1, indicating that the PCE supports TLS.
  • the route advertisement message may further include port information of the PCE, where the port information includes a port type and a port number.
  • the port types include: a TCP-based path calculation protocol PCEP port, a TLS-based PCEP port.
  • the port type includes: a PCEP port based on the TCP digest algorithm 5 option, a TCP AO based PCEP port, a TLS based PCEP port; optionally, a PCEP port based on TLS and TCP AO.
  • the determining unit 802 is configured to determine a PCE used for path calculation according to the preset selection policy and the transmission capability information of the PCE in the at least one route advertisement message.
  • the route advertisement message may be an IGP route advertisement message (refer to the method shown in FIG. 1 of the present invention) or a BGP route advertisement message (refer to the method shown in FIG. 3 of the present invention).
  • the IGP route advertisement message may be an OSPF LSA or an IS-IS LSA.
  • the location information of the PCE such as an IPv4 address or an IPv6 address, may be carried in the PCEDTLV of the OSPF LSA or the PCED of the IS-IS LSA.
  • the transmission capability information of the PCE may be extended by the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol, Three currently unused flag bits are defined in the PCE-CAP-FLAGS sub-TLV as the first flag bit, the second flag bit, and the third flag bit, respectively; further, a fourth flag bit can also be defined.
  • the specific format of the PCED sub-TLV of the PCED TLV or IS-IS protocol of OSPF can be as shown in Figure 2a.
  • the correspondence between the four flag bits extended in the PCE-ADDRESS sub-TLV in FIG. 2a and the PCE capability description may be as follows:
  • TCP MD5 PCEP over TCP MD5
  • TCP AO PCEP over TCP AO
  • TLS PCEP over TLS
  • TLS and TCP AO are supported (PCEP over TLS and TCP AO)
  • flag bits 12, 13, 14 and 15 are defined as an example, and the capability descriptions corresponding to the above-mentioned respective flag bits are only examples, and do not constitute a limitation of the present invention.
  • the IGP route advertisement message may further include the port information of the PCE, and may extend the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol, and define a sub-TLV carrying the port information of the PCE.
  • the format can be as shown in Figure 2b. You can also extend the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol to define the sub-TLV that carries the port information of the PCE.
  • the format can be as shown in Figure 2b. There are two implementations that carry the port information of the first PCE:
  • One is to define port information of two sub-TLVs carrying a PCE, where one sub-TLV carries a TCP-based PCEP (English: PCEP over TCP) port, and one sub-TLV carries a TLS-based PCEP (English: PCEP over TLS) port.
  • the four-flag bit supports TLS and sub-TLVs that support TLS and TCP AO sharing PCEP over TLS ports.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the PCE The transmission capability information also includes a fourth flag bit, which can be further defined to carry a PCEP (English: PCEP over TLS and TCP AO) port based on TLS and TCP AO.
  • the BGP route advertisement message includes the location information and the transmission capability information of the PCE, which can be implemented by extending the BGP protocol.
  • the PCE-ADDRESS sub-TLV and the PCE-CAP-FLAGS sub-TLV are carried in the BGP route advertisement message, where the PCE-ADDRESS sub-TLV is used to carry the location information of the PCE.
  • the PCE-CAP-FLAGS sub-TLV is used to carry the transmission capability information of the PCE.
  • the specific format may be the PCED TLV of the extended OSPF protocol or the PCED sub-TLV of the IS-IS protocol, as shown in FIG. 2a.
  • the BGP route advertisement message may further include port information of the PCE, where the port information includes a port type and a port number; and corresponding to the IGP route advertisement message, the port type includes: PCEP over TCP Port, PCEP over TLS port; or, the port type includes: PCEP over TCP MD5 port, base PCEP over TCP AO port, PCEP over TLS port; further, may also include PCEP over TLS and TCP AO port.
  • the BGP protocol can be extended, for example, a sub-TLV carrying the port information of the PCE in the NLRI, and the format can be as shown in FIG. 2b.
  • the port information of the PCE may be carried in two implementation manners:
  • the four-flag bit supports TLS and sub-TLVs that support TLS and TCP AO sharing PCEP over TLS ports.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the transmission capability information of the PCE further includes a fourth flag bit, a sub-TLV may be further defined for carrying the TLS-based and TCP AO's PCEP (English: PCEP over TLS and TCP AO) port.
  • the route advertisement message may include only location information and transmission capability information of one PCE; and may include location information and transmission capability information of multiple PCEs.
  • the PCC may determine the PCE for path calculation according to the transmission capability information of one or more PCEs in one route advertisement message, or according to the transmission capability information of all PCEs in the multiple route advertisement messages.
  • the preset selection strategy includes:
  • a PCE having the transmission capability supported by the PCC is selected for path calculation.
  • the PCE supporting TCP AO is preferentially selected for path calculation.
  • the PCE supporting TCP MD5 is selected for path calculation.
  • the PCE for path calculation is determined according to security requirements; the security requirements include: transport layer security, sensitive data security, transport layer and sensitive data security; PCC supports TLS and TCP AO.
  • the security requirement is transport layer and sensitive data security
  • PCE supporting TLS and TCP AO is selected for path calculation.
  • PCE supporting TCP AO is selected for path calculation; when the security requirement is sensitive data security, select PCE that supports TLS for path calculation.
  • a PCE is determined to be used for path calculation according to the priority of the PCE or the load information of the PCE or the preference of the PCC, and the preset selection policy includes:
  • a PCE having the transmission capability supported by the PCC is selected for path calculation.
  • the preset selection policy includes: if only one PCE has the transmission capability supported by the PCC, the PCE is selected for path calculation; if multiple PCEs have the foregoing The PCC supports the transmission capability, and selects a PCE with a higher priority among the plurality of PCEs for path calculation;
  • the PCE supporting TCP AO is preferentially selected for path calculation in combination with the priority of the PCE or the load information of the PCE or the preference of the PCC. In the case where neither PCE supports TCP AO, in combination with the PCE priority or PCE load information or the PCC preference, a PCE supporting TCP MD5 is selected for path calculation.
  • the priority of the PCE is used for path calculation; if the PCC supports both TCP AO and TCP MD5, if multiple PCEs support TCP AO, select a PCE with a higher priority for path calculation; if there is only one PCE Support TCP AO, then determine that the PCE is used for path calculation; if any PCE does not support TCP AO, if multiple PCEs support TCP MD5, select a higher priority PCE for path calculation, if only one PCE supports TCPMD5, determining that the PCE is used for path calculation;
  • a PCE for path calculation is determined according to the security requirement, combined with the priority of the PCE or the load information of the PCE or the preference of the PCC. Specifically, if the PCC supports the TLS and the TCP AO, when the plurality of PCEs meet the security requirements, the priority may be selected according to the priorities of the multiple PCEs or the load information of the PCE or the preferences of the PCC. A higher PCE is used for path computation; when only one PCE meets the security requirements, the PCE is determined to be used for path computation.
  • the priority information of the PCE can be referred to the current standard specification, and is carried in the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol.
  • the PCE load information includes a load capacity of the PCE, a current load condition, and the like.
  • a PCE with a strong load capacity and a small current load can be selected for path calculation.
  • the preset selection policy may also be combined with the local policy of the PCC.
  • the local policy is to select a PCE that supports the most transmission capability; of course, the local policy of the PCC may be statically configured or dynamically adjusted according to requirements.
  • the PCC provided by the embodiment of the present invention receives the route advertisement message carrying the PCE transmission capability information, and selects the PCE matching the transmission capability of the PCE for the path calculation according to the transmission capability of the PCE and the preset selection policy, which can improve the relationship between the PCC and the PCE. Establish a PCEP session success rate to improve path computation effectiveness.
  • FIG. 9 is a structural block diagram of another communication device according to an embodiment of the present invention.
  • the communication device is specifically a BGP router, and is used to implement the method shown in FIG. 3 of the present invention.
  • the system includes: a receiving unit 901, a generating unit 902, and a sending unit 903;
  • the receiving unit 901 is configured to receive at least one IGP route advertisement message from the AS domain of the autonomous system, where the IGP route advertisement message includes location information and transmission capability information of the path calculation unit PCE, where the transmission capability information of the PCE includes a first flag bit, a second flag bit, and a third flag bit; wherein the first flag bit is used to indicate whether the PCE supports a Transmission Control Protocol TCP Digest Algorithm 5 option; the second flag bit is used to indicate Whether the PCE supports the TCP authentication configuration option AO; the third flag is used to indicate whether the PCE supports the transport layer security TLS; optionally, the transmission capability information of the PCE further includes a fourth flag bit for indicating Whether the PCE supports TLS and TCP AO;
  • the IGP route advertisement message is an OSPF LSA or an IS-IS LSA.
  • the BGP router may specifically be a BGP speaker.
  • the transmission capability information of the PCE can be implemented by extending the PCED TLV of the OSPF protocol or the PCE-CAP-FLAGS sub-TLV of the PCED sub-TLV of the IS-IS protocol, in the PCE-CAP-FLAGS sub-TLV. Defining three currently unused flag bits, as the first flag bit, the second flag bit, and the third flag bit, respectively, are used to indicate whether the first PCE supports the TCP MD5 option, and whether the first PCE supports TCP AO, whether the first PCE supports TLS; further, a fourth flag bit may also be defined to indicate whether the first PCE supports TLS and TCP AO.
  • the format of the PCED sub-TLV of the PCED TLV or IS-IS protocol of OSPF can be as shown in Figure 2a.
  • the correspondence between the four flag bits extended in the PCE-ADDRESS sub-TLV and the PCE capability description in FIG. 2a can be as follows:
  • TCP MD5 PCEP over TCP MD5
  • TCP AO PCEP over TCP AO
  • the generating unit 902 is configured to generate a border gateway protocol BGP route advertisement message according to the at least one IGP route advertisement message, where the BGP route advertisement message includes location information and transmission of the PCE in the at least one IGP route advertisement message Capability information;
  • the communication device receives two IGP route advertisement messages: a first IGP route advertisement message and a second IGP route advertisement message, where the first IGP route advertisement message includes location information and transmission capability information of the first PCE.
  • the second route advertisement message includes the location information and the transmission capability information of the second PCE, where the first IGP route advertisement message and the second IGP route advertisement message are from an AS domain; then the communication device announces the message according to the first route And generating, by the second route advertisement message, the BGP route advertisement message, where the BGP route advertisement message includes location information and transmission capability information of the first PCE, and location information and transmission capability information of the second PCE.
  • the communication device may generate a BGP route advertisement message according to only one IGP route advertisement message, or generate a BGP route advertisement message according to multiple IGP route advertisement messages received by an AS domain, and multiple The location information and transmission capability information of each PCE carried in the IGP route advertisement message is sent to other AS domains through a BGP route advertisement message.
  • the BGP protocol can be extended.
  • the PCE-ADDRESS sub-TLV and the PCE-CAP-FLAGS sub-TLV are carried in the BGP route advertisement message.
  • the transmission capability information of the PCE may also be used to identify the transmission capability of the PCE by extending the capability parameter of the BGP protocol (English: capability optional parameter).
  • capability parameter of the BGP protocol English: capability optional parameter.
  • the sending unit 903 is configured to send the BGP route advertisement message to an AS domain other than the AS.
  • the at least one IGP route advertisement message is from a first AS domain, and the BGP router is located on the first AS and the second AS boundary.
  • the sending unit 903 sends the BGP route advertisement message to the second AS to notify the members of the second AS of the transmission capability of the PCE.
  • the IGP route advertisement message may further include port information of the PCE, where the port information includes a port type and a port number, and the port type includes: a TCP-based PCEP (English: PCEP over TCP) port. TLS-based PCEP (English: PCEP over TLS) port.
  • the port type includes: PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, PCEP over TLS based on TLS (English: PCEP over TLS) Port; further, it may also include a PCEP (English: PCEP over TLS and TCP AO) port based on TLS and TCP AO.
  • the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol may be extended, and the sub-TLV carrying the port information of the first PCE may be defined, and the format may be as shown in FIG. 2b. The method shown in FIG. 1 is not repeated here.
  • the BGP route advertisement message may further include port information of the PCE.
  • the BGP protocol can be extended.
  • the sub-TLV carrying the port information of the PCE is defined in the NLRI, and the format can be as shown in FIG. 2b. Similar to the extension of OSPF or IS-IS, there are two implementations that carry port information of the PCE:
  • One is to define port information of two sub-TLVs carrying a PCE, where one sub-TLV carries a TCP-based PCEP (English: PCEP over TCP) port, and one sub-TLV carries a TLS-based PCEP (English: PCEP over TLS) port.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the first The PCE transmission capability information also includes a fourth flag bit, which can be further defined to carry a PCEP (English: PCEP over TLS and TCP AO) port based on TLS and TCP AO.
  • the communication device further includes an checking unit, configured to check the IGP route before the generating unit 902 generates the BGP route advertisement message after the receiving unit 901 receives the IGP route advertisement message. Whether the transmission capability information of the PCE is included in the announcement message. If the check determines that the IGP route advertisement message includes the transmission capability information of the PCE, the generating unit 902 generates a BGP route advertisement message including the location information and the transmission capability information of the PCE; if the check determines If the transmission capability information of the PCE is not included in the IGP route advertisement message, the communication device processes according to an existing standard specification.
  • an checking unit configured to check the IGP route before the generating unit 902 generates the BGP route advertisement message after the receiving unit 901 receives the IGP route advertisement message. Whether the transmission capability information of the PCE is included in the announcement message. If the check determines that the IGP route advertisement message includes the transmission capability information of the PCE, the generating unit 902 generates a BGP route advertisement message including the location information and the transmission
  • the IGP route advertisement message may include only location information and transmission capability information of one PCE, and may also include location information and transmission capability information of multiple PCEs.
  • the BGP route advertisement message includes location information and transmission capability information of multiple PCEs in the IGP route advertisement message.
  • the communication device provided by the embodiment of the present invention can implement the PCE transmission capability notification between the ASs through the extended BGP protocol, and can ensure that the PCC session is effectively established between the PC and the PCE, thereby improving the path calculation efficiency and success rate between the PCC and the PCE.
  • FIG. 10 it is a block diagram of a communication device according to an embodiment of the present invention.
  • the communication device is specifically an IGP router, and is used to implement the method shown in FIG. 1 of the present invention.
  • IGP router an IGP router
  • the generating unit 1001 is configured to generate an IGP route advertisement message, where the route advertisement message includes location information and transmission capability information of the first PCE, where the transmission capability information of the first PCE includes a first flag bit, a second flag bit, and a third flag bit, wherein the first flag bit is used to indicate whether the first PCE supports a transmission control protocol TCP message digest algorithm fifth version MD5 option (English: PCEP over TCP MD5); the second flag bit Determining whether the first PCE supports a TCP authentication configuration option AO (English: PCEP over TCP AO); the third flag bit is used to indicate whether the first PCE supports transmission Layer Security TLS (English: PCEP over TLS).
  • TCP message digest algorithm fifth version MD5 option English: PCEP over TCP MD5
  • the second flag bit Determining whether the first PCE supports a TCP authentication configuration option AO (English: PCEP over TCP AO)
  • the third flag bit is used to indicate whether the first PCE supports transmission Layer Security TLS (English: PCEP over TLS).
  • the transmission capability information of the first PCE further includes a fourth flag bit, where the fourth flag bit is used to indicate whether the first PCE supports TLS and TCP AO.
  • the sending unit 1002 is configured to send the IGP route advertisement message to the domain where the communication device is located, and generally can also say that the IGP route advertisement message is flooded to indicate to the member in the domain where the communication device is located.
  • the transmission capability of the first PCE is configured to send the IGP route advertisement message to the domain where the communication device is located.
  • the route advertisement message may further include port information of the first PCE, where the port information includes a port type and a port number.
  • the port types include: TCP-based PCEP (English: PCEP over TCP) port, TLS-based PCEP (English: PCEP over TLS) port.
  • the port type includes: PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, PCEP over TLS based on TLS (English: PCEP over TLS) a port; further optionally, if the transmission capability information of the first PCE further includes a fourth flag bit, correspondingly the port type comprises: a PCEP (TCPEP over TLS and TCP AO) port based on TLS and TCP AO .
  • the IGP includes OSPF, IS-IS; correspondingly, the communication device is an OSPF router, the domain of the communication device is an OSPF domain, and the route advertisement message is an OSPF LSA; or the communication device is an IS- The IS router is in the IS-IS domain, and the route advertisement message is an IS-IS LSA.
  • the location information of the first PCE may be carried in the PCE-ADDRESSsub-TLV in the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol; and the OSPF is extended.
  • the PCED TLV of the protocol or the PCED sub-TLV of the IS-IS protocol defines three currently unused flag bits in the PCE Capability Flag (PCE-CAP-FLAGS) sub-TLV as the first flag and the second flag described above.
  • Flag bit and third flag bit respectively for indicating Whether the first PCE supports the TCP MD5 option, whether the first PCE supports TCP AO, whether the first PCE supports TLS; further, a fourth flag bit may be defined to indicate the first Whether PCE supports TLS and TCP AO.
  • the format of the PCED sub-TLV of the PCED TLV or IS-IS protocol of OSPF can be as shown in Figure 2a.
  • the correspondence between the four flag bits extended in the PCE-ADDRESS sub-TLV and the PCE capability description in FIG. 2a can be as follows:
  • TCP MD5 PCEP over TCP MD5
  • TCP AO PCEP over TCP AO
  • TLS PCEP over TLS
  • TLS and TCP AO are supported (PCEP over TLS and TCP AO)
  • the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol may be extended to define a sub-TLV carrying the port information of the first PCE, and the format may be as shown in FIG. 2b.
  • One is to define port information of two sub-TLVs carrying a PCE, where one sub-TLV carries a TCP-based PCEP (English: PCEP over TCP) port, and one sub-TLV carries a TLS-based PCEP (English: PCEP over TLS) port.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the first The PCE transmission capability information also includes a fourth flag bit, which can be further defined to carry a PCEP (English: PCEP over TLS and TCP AO) port based on TLS and TCP AO.
  • the communication device may further include a receiving unit, configured to receive registration information of the first PCE, where the registration information includes a transmission capability of the first PCE, before generating the route advertisement message.
  • the registration information may also include a range of PCE path calculations, neighboring PCEs, communication capabilities, and path computation capabilities.
  • the route advertisement message may further include location information and transmission capability information of the second PCE.
  • the port information of the second PCE is further included.
  • the receiving unit is further configured to: before the generating the route advertisement message, receive registration information of the second PCE, where the registration information includes a transmission capability of the second PCE.
  • the communication device provided by the embodiment of the present invention extends the OSPF protocol PCED TLV or the PCED sub-TLV of the IS-IS protocol, and defines a flag bit to indicate the transmission capability of the PCE, so that the PCE transmission capability can be notified, so that the PCC can select and
  • the PCE with its own transmission capability ensures that the PCEP session is effectively established between the PCC and the PCE, thereby improving the efficiency and success rate of path calculation between the PCC and the PCE.
  • FIG. 11 is a schematic structural diagram of a communication device according to an embodiment of the present invention.
  • the communication device is specifically a PCC network element, and is used to implement the method shown in FIG. 4 of the present invention.
  • the device 1100 includes: a processor 1101, a memory 1102, a communication interface 1103, and a bus 1104;
  • the processor 1101, the memory 1102, and the communication interface 1103 are mutually connected by a bus 1104.
  • the bus 1104 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus. Wait.
  • PCI peripheral component interconnect
  • EISA extended industry standard architecture
  • the bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in Figure 11, but it does not mean that there is only one bus or one type of bus.
  • the memory 1102 is configured to store a program.
  • the program can include program code, the program code including computer operating instructions.
  • Memory 1102 may contain high speed random access memory (random Access memory (RAM) may also include non-volatile memory, such as at least one disk storage.
  • RAM random Access memory
  • the communication interface 1103 is configured to communicate with other communication devices.
  • the processor 1101 executes the program stored in the memory 1102, and the method for determining the path calculation unit provided by the embodiment of the present invention includes:
  • the transmission capability information of the PCE includes a first flag bit, a second flag bit, and a third flag bit;
  • the first flag is used to indicate whether the PCE supports the Transmission Control Protocol TCP Digest Algorithm 5 option;
  • the second flag is used to indicate whether the first PCE supports the TCP authentication configuration option AO;
  • the transmission capability information of the PCE further includes a fourth flag bit, where the fourth flag bit is used to indicate whether the PCE supports TLS and TCP AO;
  • the route advertisement message may further include port information of the PCE, where the port information includes a port type and a port number.
  • the port types include: a TCP-based path calculation protocol PCEP port, a TLS-based PCEP port.
  • the port type includes: a PCEP port based on the TCP digest algorithm 5 option, a TCP AO based PCEP port, a TLS based PCEP port; optionally, a PCEP port based on TLS and TCP AO.
  • the route advertisement message may be an IGP route advertisement message (refer to the method shown in FIG. 1 of the present invention) or a BGP route advertisement message (refer to the method shown in FIG. 3 of the present invention).
  • the IGP route advertisement message may be an OSPF LSA or an IS-IS LSA.
  • the location information of the PCE such as an IPv4 address or an IPv6 address, may be carried in the PCED TLV or IS-IS LSA of the OSPF LSA.
  • the transmission capability information of the PCE can be extended by the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol in the PCE-CAP-FLAGS sub-TLV.
  • three currently unused flags as the above a flag bit, a second flag bit, and a third flag bit; further, a fourth flag bit can also be defined.
  • the specific format of the PCED sub-TLV of the PCED TLV or IS-IS protocol of OSPF can be as shown in Figure 2a.
  • the correspondence between the four flag bits extended in the PCE-ADDRESS sub-TLV in FIG. 2a and the PCE capability description may be as follows:
  • TCP MD5 PCEP over TCP MD5
  • TCP AO PCEP over TCP AO
  • TLS PCEP over TLS
  • TLS and TCP AO are supported (PCEP over TLS and TCP AO)
  • flag bits 12, 13, 14 and 15 are defined as an example, and the capability descriptions corresponding to the above-mentioned respective flag bits are only examples, and do not constitute a limitation of the present invention.
  • the IGP route advertisement message may further include the port information of the PCE, and may extend the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol, and define a sub-TLV carrying the port information of the PCE.
  • the format can be as shown in Figure 2b. You can also extend the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol to define the sub-TLV that carries the port information of the PCE.
  • the format can be as shown in Figure 2b. There are two implementations that carry the port information of the first PCE:
  • One is to define port information of two sub-TLVs carrying a PCE, where one sub-TLV carries a TCP-based PCEP (English: PCEP over TCP) port, and one sub-TLV carries a TLS-based PCEP (English: PCEP over TLS) port.
  • the four-flag bit supports TLS and sub-TLVs that support TLS and TCP AO sharing PCEP over TLS ports.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the transmission capability information of the PCE further includes a fourth flag bit, a sub-TLV may be further defined for carrying the TLS-based and TCP AO's PCEP (English: PCEP over TLS and TCP AO) port.
  • the BGP route advertisement message includes the location information and the transmission capability information of the PCE, which can be implemented by extending the BGP protocol.
  • the PCE-ADDRESS sub-TLV and the PCE-CAP-FLAGS sub-TLV are carried in the BGP route advertisement message, where the PCE-ADDRESS sub-TLV is used to carry the location information of the PCE.
  • the PCE-CAP-FLAGS sub-TLV is used to carry the transmission capability information of the PCE.
  • the specific format may be the PCED TLV of the extended OSPF protocol or the PCED sub-TLV of the IS-IS protocol, as shown in FIG. 2a.
  • the BGP route advertisement message may further include port information of the PCE, where the port information includes a port type and a port number; and corresponding to the IGP route advertisement message, the port type includes: PCEP over TCP Port, PCEP over TLS port; or, the port type includes: PCEP over TCP MD5 port, base PCEP over TCP AO port, PCEP over TLS port; further, may also include PCEP over TLS and TCP AO port.
  • the BGP protocol can be extended, for example, a sub-TLV carrying the port information of the PCE in the NLRI, and the format can be as shown in FIG. 2b.
  • the port information of the PCE may be carried in the foregoing two implementation manners.
  • the route advertisement message may include only location information and transmission capability information of one PCE; and may include location information and transmission capability information of multiple PCEs.
  • the PCC may determine the PCE for path calculation according to the transmission capability information of one or more PCEs in one route advertisement message, or according to the transmission capability information of all PCEs in the multiple route advertisement messages.
  • the preset selection strategy includes:
  • a PCE having the transmission capability supported by the PCC is selected for path calculation.
  • the PCE supporting TCP AO is preferentially selected for path calculation.
  • the PCE supporting TCP MD5 is selected for path calculation.
  • the PCE for path calculation is determined according to security requirements; the security requirements include: transport layer security, sensitive data security, transport layer and sensitive data security; Specifically, if the PCC supports TLS and TCP AO, when the security requirement is the transport layer and the sensitive data security, the PCE supporting TLS and TCP AO is selected for path calculation; when the security requirement is the transport layer, the support is selected. The PCE of TCP AO is used for path calculation; when the security requirement is sensitive data security, PCE supporting TLS is selected for path calculation.
  • a PCE is determined to be used for path calculation according to the priority of the PCE or the load information of the PCE or the preference of the PCC, and the preset selection policy includes:
  • a PCE having the transmission capability supported by the PCC is selected for path calculation.
  • the preset selection policy includes: if only one PCE has the transmission capability supported by the PCC, the PCE is selected for path calculation; if multiple PCEs have the foregoing The PCC supports the transmission capability, and selects a PCE with a higher priority among the plurality of PCEs for path calculation;
  • the PCE supporting the TCP AO is preferentially selected for path calculation in combination with the PCE priority or the PCE load information or the PCC preference, and is not supported by any PCE.
  • a PCE supporting TCP MD5 is selected for path calculation.
  • the priority of the PCE is used for path calculation; if the PCC supports both TCP AO and TCP MD5, if multiple PCEs support TCP AO, select a PCE with a higher priority for path calculation; if there is only one PCE Support TCP AO, then determine that the PCE is used for path calculation; if any PCE does not support TCP AO, if multiple PCEs support TCP MD5, select a higher priority PCE for path calculation, if only one PCE supports TCP MD5, determining that the PCE is used for path calculation;
  • a PCE for path calculation is determined according to the security requirement, combined with the priority of the PCE or the load information of the PCE or the preference of the PCC. Specifically, if the PCC supports the TLS and the TCP AO, when the plurality of PCEs meet the security requirements, the priority may be selected according to the priorities of the multiple PCEs or the load information of the PCE or the preferences of the PCC. A higher PCE is used for path computation; when only one PCE meets the security requirements, the PCE is determined to be used for path computation.
  • the memory 1102 is further configured to save the preset selection policy.
  • the priority information of the PCE can be referred to the current standard specification, and is carried in the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol.
  • the PCE load information includes a load capacity of the PCE, a current load condition, and the like.
  • a PCE with a strong load capacity and a small current load can be selected for path calculation.
  • the preset selection policy may also be combined with the local policy of the PCC.
  • the local policy is to select a PCE that supports the most transmission capability; of course, the local policy of the PCC may be statically configured or dynamically adjusted according to requirements.
  • the PCC provided by the embodiment of the present invention receives the route advertisement message carrying the PCE transmission capability information, and selects the PCE matching the transmission capability of the PCE for the path calculation according to the transmission capability of the PCE and the preset selection policy, which can improve the relationship between the PCC and the PCE. Establish the success rate of the PCEP session to improve the efficiency of path calculation.
  • FIG. 12 is a schematic structural diagram of another communication device according to an embodiment of the present invention.
  • the communication device is specifically a BGP router, and is used to implement the method shown in FIG. 3 of the present invention.
  • the device 1200 includes: a processor 1201, a memory 1202, a communication interface 1203, and a bus 1204;
  • the processor 1201, the memory 1202, and the communication interface 1203 are connected to each other through a bus 1204; the bus 1204 may be a PCI bus or an EISA bus or the like.
  • the bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in Figure 12, but it does not mean that there is only one bus or one type of bus.
  • the communication interface 1203 is configured to communicate with other communication devices.
  • the memory 1202 is configured to store a program.
  • the program may include program code, the program The code includes computer operating instructions.
  • the memory 1202 may include high speed RAM, and may also include non-volatile memory, such as at least one disk memory.
  • the processor 1201 executes the program stored in the memory 1202, and the method for performing the notification transmission capability provided by the embodiment of the present invention includes:
  • the transmission capability information of the PCE includes a first flag bit, a second flag bit, and a third flag bit, wherein the first flag bit is used to indicate whether the PCE supports a transmission control protocol TCP digest algorithm 5 option; the second flag bit is used to indicate whether the PCE supports a TCP authentication configuration option AO; The third flag is used to indicate whether the PCE supports the transport layer security TLS; optionally, the transmission capability information of the PCE further includes a fourth flag bit for indicating whether the PCE supports TLS and TCP AO;
  • the at least one IGP route advertisement message is from a first AS domain, where the BGP router is located on the first AS and the second AS boundary, sending the BGP route advertisement message to the second AS, to The member in the second AS announces the transmission capability of the first PCE.
  • the communication device 1200 may specifically be a BGP speaker.
  • the IGP route advertisement message is an OSPF LSA or an IS-IS LSA.
  • the BGP router may specifically be a BGP speaker.
  • the transmission capability information of the PCE can be implemented by extending the PCED TLV of the OSPF protocol or the PCE-CAP-FLAGS sub-TLV of the PCED sub-TLV of the IS-IS protocol, and defining three currents in the PCE-CAP-FLAGS sub-TLV.
  • the unused flag bit, as the first flag bit, the second flag bit, and the third flag bit, are respectively used to indicate whether the first PCE supports the TCP MD5 option, and whether the first PCE supports TCP AO. Whether the first PCE supports TLS; further, the fourth flag can also be defined Bit for indicating whether the first PCE supports TLS and TCP AO.
  • the format of the PCED sub-TLV of the PCED TLV or IS-IS protocol of OSPF can be as shown in Figure 2a.
  • Figure 2a For details, refer to the method provided in the embodiment of the present invention, and details are not described herein again.
  • the BGP protocol can be extended.
  • the PCE-ADDRESS sub-TLV and the PCE-CAP-FLAGS sub-TLV are carried in the BGP route advertisement message.
  • the transmission capability information of the PCE may also be used to identify the transmission capability of the PCE by extending the capability parameter of the BGP protocol (English: capability optional parameter).
  • capability parameter of the BGP protocol English: capability optional parameter.
  • the IGP route advertisement message may further include port information of the PCE, where the port information includes a port type and a port number, and the port type includes: a TCP-based PCEP (English: PCEP over TCP) port. TLS-based PCEP (English: PCEP over TLS) port.
  • the port type includes: PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, PCEP over TLS based on TLS (English: PCEP over TLS) Port; further, it may also include a PCEP (English: PCEP over TLS and TCP AO) port based on TLS and TCP AO.
  • the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol may be extended, and the sub-TLV carrying the port information of the first PCE may be defined, and the format may be as shown in FIG. 2b. The method shown in FIG. 1 is not repeated here.
  • the BGP route advertisement message may further include port information of the PCE.
  • the BGP protocol can be extended.
  • the sub-TLV carrying the port information of the PCE is defined in the NLRI, and the format can be as shown in FIG. 2b. Similar to the extension of OSPF or IS-IS, there are two implementations that carry port information of the PCE:
  • TCP MD5 option and support TCP AO Sharing a sub-TLV carrying a PCEP over TCP port, a sub-TLV supporting a TLS using a PCEP over TLS port; optionally, if the transmission capability information of the first PCE further includes a fourth flag bit, then TLS and TLS are supported.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the transmission capability information of the first PCE further includes a fourth flag bit, a sub-TLV may be further defined for carrying a PCEP over TCP and TCP AO based port (English: PCEP over TLS and TCP AO).
  • the method further includes: checking whether the at least one IGP route advertisement message includes the transmission capability information of the PCE; Determining that the at least one IGP route advertisement message includes the transmission capability information of the PCE, and generating the BGP route advertisement message; if it is determined that the at least one IGP route advertisement message does not include the transmission capability information of the PCE, according to the existing standard The specification is processed.
  • the communication device may generate a BGP route advertisement message according to only one IGP route advertisement message, or generate a BGP route advertisement message according to multiple IGP route advertisement messages received by an AS domain, and multiple The location information and transmission capability information of each PCE carried in the IGP route advertisement message is sent to other AS domains through a BGP route advertisement message.
  • the communication device receives two IGP route advertisement messages: a first IGP route advertisement message and a second IGP route advertisement message, where the first IGP route advertisement message includes location information and transmission capability information of the first PCE.
  • the second route advertisement message includes the location information and the transmission capability information of the second PCE, where the first IGP route advertisement message and the second IGP route advertisement message are from an AS domain; then the communication device announces the message according to the first route And generating, by the second route advertisement message, the BGP route advertisement message, where the BGP route advertisement message includes location information and transmission capability information of the first PCE, and location information and transmission capability information of the second PCE.
  • the IGP route advertisement message may include only location information and transmission capability information of one PCE, and may also include location information and transmission capability information of multiple PCEs. Accordingly, The BGP route advertisement message includes location information and transmission capability information of multiple PCEs in the IGP route advertisement message.
  • the communication device provided by the embodiment of the present invention can implement the PCE transmission capability notification between the ASs through the extended BGP protocol, and can ensure that the PCC session is effectively established between the PC and the PCE, thereby improving the path calculation efficiency and success rate between the PCC and the PCE.
  • FIG. 13 is a schematic structural diagram of still another communication device according to an embodiment of the present invention.
  • the communication device is specifically an IGP router, and is used to implement the method shown in FIG. 1 of the present invention.
  • the device 1300 includes: a processor 1301, a memory 1302, a communication interface 1303, and a bus 1304;
  • the processor 1301, the memory 1302, and the communication interface 1303 are mutually connected by a bus 1304; the bus 1304 may be a PCI bus or an EISA bus or the like.
  • the bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in FIG. 13, but it does not mean that there is only one bus or one type of bus.
  • the communication interface 1303 is configured to communicate with other communication devices.
  • the memory 1302 is configured to store a program.
  • the program can include program code, the program code including computer operating instructions.
  • the memory 1302 may include a high speed RAM, and may also include a non-volatile memory such as at least one disk memory.
  • the processor 1301 executes a program stored in the memory 1302, and the method for performing the notification transmission capability provided by the embodiment of the present invention includes:
  • the transmission capability information of the first PCE includes a first flag bit, a second flag bit, and a third flag bit;
  • the first flag bit is used to indicate whether the first PCE supports a transmission control protocol TCP message digest algorithm fifth version MD5 option (English: PCEP over TCP MD5);
  • the second flag bit is used to indicate the first Whether a PCE supports the TCP authentication configuration option AO (English: PCEP over TCP AO);
  • the third flag bit is used to indicate whether the first PCE supports transport layer security TLS (English)
  • the transmission capability information of the first PCE further includes a fourth flag bit, where the fourth flag bit is used to indicate whether the first PCE supports TLS and TCP AO. PCEP over TLS and TCP AO);
  • flooding (English: flood) the IGP route advertisement message.
  • the route advertisement message may further include port information of the first PCE, where the port information includes a port type and a port number.
  • the port types include: TCP-based PCEP (English: PCEP over TCP) port, TLS-based PCEP (English: PCEP over TLS) port.
  • the port type includes: PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, PCEP over TLS based on TLS (English: PCEP over TLS) a port; further optionally, if the transmission capability information of the first PCE further includes a fourth flag bit, correspondingly the port type comprises: a PCEP (TCPEP over TLS and TCP AO) port based on TLS and TCP AO .
  • the IGP includes OSPF, IS-IS; correspondingly, the communication device is an OSPF router, the domain of the communication device is an OSPF domain, and the route advertisement message is an OSPF LSA; or the communication device is an IS- The IS router is in the IS-IS domain, and the route advertisement message is an IS-IS LSA.
  • the location information of the first PCE may be carried in the PCE-ADDRESSsub-TLV in the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol; and the OSPF is extended.
  • the PCED TLV of the protocol or the PCED sub-TLV of the IS-IS protocol defines three currently unused flag bits in the PCE Capability Flag (PCE-CAP-FLAGS) sub-TLV as the first flag and the second flag described above.
  • the flag bit and the third flag bit are respectively used to indicate whether the first PCE supports the TCP MD5 option, whether the first PCE supports TCP AO, whether the first PCE supports TLS, and further, may further define a fourth A flag bit for indicating whether the first PCE supports TLS and TCP AO.
  • PCED TLV of OSPF or PCED of IS-IS protocol The format of the sub-TLV can be as shown in Figure 2a. Specifically, the correspondence between the four flag bits extended in the PCE-ADDRESS sub-TLV and the PCE capability description in FIG. 2a can be as follows:
  • TCP MD5 PCEP over TCP MD5
  • TCP AO PCEP over TCP AO
  • TLS PCEP over TLS
  • TLS and TCP AO are supported (PCEP over TLS and TCP AO)
  • the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol may be extended to define a sub-TLV carrying the port information of the first PCE, and the format may be as shown in FIG. 2b.
  • One is to define port information of two sub-TLVs carrying a PCE, where one sub-TLV carries a TCP-based PCEP (English: PCEP over TCP) port, and one sub-TLV carries a TLS-based PCEP (English: PCEP over TLS) port.
  • the other is to define three sub-TLVs carrying PCEP (English: PCEP over TCP MD5) port based on TCP MD5 option, PCEP (English: PCEP over TCP AO) port based on TCP AO, and PCEP based on TLS (English) :PCEP over TLS) port. Further, if the transmission capability information of the first PCE further includes a fourth flag bit, a sub-TLV may be further defined for carrying a PCEP over TCP and TCP AO based port (English: PCEP over TLS and TCP AO).
  • the method further includes: receiving registration information of the first PCE, where the registration information includes a transmission capability of the first PCE.
  • the registration information may further include a range of the first PCE path calculation, a neighboring PCE, and a communication energy. Force and path calculation capabilities, etc.
  • the memory 1302 is further configured to save registration information of the first PCE.
  • the route advertisement message may further include location information and transmission capability information of the second PCE.
  • the port information of the second PCE is further included.
  • the receiving unit is further configured to: before the generating the route advertisement message, receive registration information of the second PCE, where the registration information includes a transmission capability of the second PCE.
  • the communication device defines the transmission capability of the PCE by extending the PCED TLV of the OSPF protocol or the PCED sub-TLV of the IS-IS protocol, so that the PCE transmission capability can be notified, so that the PCC can select and transmit the PCE.
  • the ability to match the PCE ensures that the PCEP session is effectively established between the PCC and the PCE, thereby improving the efficiency and success rate of path calculation between the PCC and the PCE.
  • the steps of a method or algorithm described in connection with the embodiments disclosed herein may be implemented by a software module executed by a processor.
  • the software module can be placed in a random access memory (English: RAM), read only memory (English: ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, or the art. Any other form of storage medium.

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Abstract

本发明实施例涉及一种确定路径计算单元的方法及通信设备，通过在路由通告消息中携带PCE的位置信息和传输能力信息，通告给PCC，使得PCC可以根据路由通告消息中的PCE的传输能力信息，选择满足该PCC传输能力的PCE用于路径计算，从而避免PCC与PCE间因传输能力不匹配，导致建立PCEP会话失败的问题。

Description

确定路径计算单元的方法及通信设备 技术领域
本发明涉及通信领域，尤其涉及一种确定路径计算单元(path computation element，简称PCE)方法及通信设备。
背景技术
PCE是网络中专门负责路径计算的功能实体，可以是一个独立的网络设备，或者网络设备上的装置或应用程序；PCE基于已知的网络拓扑结构，以及约束条件，根据路径计算客户(path computation client，简称PCC)的请求计算出一条满足约束条件的路径。
通常，PCC和PCE之间以及PCE与PCE之间是通过路径计算协议(PCE communication protocol，简称PCEP)通信，提交路径计算请求并获得路径计算结果。PCC先通过PCE发现机制得到PCE的位置、路径计算的范围、相邻PCE、路径计算能力等信息，来选取一个符合要求的PCE提交路径计算请求。根据标准，通常PCC与PCE之间先建立传输控制协议(transmission control protocol，简称TCP)连接,然后基于TCP连接建立PCEP会话，也就是PCEP over TCP。在需要对TCP连接提供保护的情况下，可以采用TCP消息摘要算法第五版(message-digest algorithm 5，简称MD5)选项；但是随着网络技术的发展，TCP认证配置选项(authority option，简称AO)取代了TCP MD5，还出现了提供保密性和数据完整性的传输层安全(transport layer security，简称TLS)的加密协议。。
在各种传输协议都存在的情形下，如何有效的建立PCEP会话成为一个亟待解决的问题。
发明内容
本发明提供了一种确定PCE的方法及通信设备，用以解决如何有效的建立PCEP会话的问题。
第一方面，本发明实施例提供了一种确定路径计算单元的方法，包括：
路径计算客户PCC接收至少一个路由通告消息，所述路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；
所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项；所述第二标志位用于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；
根据预设选取策略和所述至少一个路由通告消息中PCE的传输能力信息，确定用于路径计算的PCE。
在第一方面的第一种可能实现方式中，所述路由通告消息中还包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；
所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口；或者，
所述端口类型包括：基于TCP MD5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口。
根据第一方面或第一方面的第一种可能实现方式，在第一方面的第二种可能实现方式中，所述预定选取策略包括：
选取具备所述PCC支持的传输能力的PCE用于路径计算；
若所述PCC支持TCP MD5，则选取支持TCP MD5的PCE用于路径计算；或者
若所述PCC支持TCP AO，则选取支持TCP AO的PCE用于路径计算；或者
所述PCC支持TLS，则选取支持TLS的PCE用于路径计算。
根据第一方面或第一方面的第一种可能实现方式或第一方面的第二种可能 实现方式，在第一方面的第三种可能实现方式中，所述预定选取策略包括：
选取具备所述PCC支持的传输能力的PCE用于路径计算；
若所述PCC既支持TCP AO也支持TCP MD5，则优先选取支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，选取支持TCP MD5的PCE用于路径计算；或者
若所述PCC支持TLS和TCP AO，则根据安全性需求，选取用于路径计算的PCE，所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全；或者
结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个具备所述PCC支持的传输能力的PCE用于路径计算；
若所述PCC既支持TCP AO也支持TCP MD5，则结合PCE的优先级或PCE的负载信息或所述PCC的喜好，优先选取一个支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，结合PCE的优先级，选取一个支持TCP MD5的PCE用于路径计算；或者
若所述PCC支持TLS和TCP AO，则根据安全性需求，结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个用于路径计算的PCE，所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全。
根据第一方面和第一方面的第一种至第三种可能实现方式中的任一种，在第一方面的第四种可能实现方式中，所述路由通告消息包括内部网关协议IGP路由通告消息，边界网关协议BGP路由通告消息。
第二方面，本发明实施例提供了一种通信设备，包括：
接收单元，用于接收至少一个路由通告消息，所述路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项；所述第二标志位用 于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；
确定单元，用于根据预设选取策略和所述至少一个路由通告消息中PCE的传输能力信息，确定用于路径计算的PCE。
在第二方面的第一种可能实现方式中，所述路由通告消息中还包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；
所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口；或者，
所述端口类型包括：基于TCP MD5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口。
根据第二方面或第二方面的第一种可能实现方式，在第二方面的第二种可能实现方式中，所述预定选取策略包括：
选取具备所述PCC支持的传输能力的PCE用于路径计算；
若所述PCC支持TCP MD5，则选取支持TCP MD5的PCE用于路径计算；或者
若所述PCC支持TCP AO，则选取支持TCP AO的PCE用于路径计算；或者
所述PCC支持TLS，则选取支持TLS的PCE用于路径计算。
根据第二方面或第二方面的第一种可能实现方式第二方面的第二种可能实现方式，在第二方面的第三种可能实现方式中，所述预定选取策略包括：
选取具备所述PCC支持的传输能力的PCE用于路径计算；
若所述PCC既支持TCP AO也支持TCP MD5，则优先选取支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，选取支持TCP MD5的PCE用于路径计算；或者
若所述PCC支持TLS和TCP AO，则根据安全性需求，选取用于路径计算的PCE，所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全；或者
结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个具备所 述PCC支持的传输能力的PCE用于路径计算；
若所述PCC既支持TCP AO也支持TCP MD5，则结合PCE的优先级或PCE的负载信息或所述PCC的喜好，优先选取一个支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，结合PCE的优先级，选取一个支持TCP MD5的PCE用于路径计算；或者
若所述PCC支持TLS和TCP AO，则根据安全性需求，结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个用于路径计算的PCE，所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全
第三方面，本发明实施例提供了一种通信设备，包括：
接收单元，用于接收来自自治系统AS域的至少一个内部网关协议IGP路由通告消息，所述IGP路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项；所述第二标志位用于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；
生成单元，用于根据所述至少一个IGP路由通告消息生成边界网关协议BGP路由通告消息，所述BGP路由通告消息中包括所述至少一个IGP路由通告消息中的PCE的位置信息和传输能力信息；
发送单元，用于将所述BGP路由通告消息发送到所述AS域以外的AS域。
在第三方面的第一种可能实现方式中，所述IGP路由通告消息中还包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口；或者，所述端口类型包括：基于TCP消息摘要算法第五版MD5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口；
相应地，所述BGP路由通告消息中还包括所述至少一个IGP路由通告消息 中的PCE的端口信息。
第四方面，本发明实施例提供了一种通信设备，包括：
生成单元，用于生成内部网关协议IGP路由通告消息，所述IGP路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项；所述第二标志位用于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；
发送单元，用于向所述通信设备所在域发送所述IGP路由通告消息。
在第四方面的第一种可能实现方式中，所述IGP路由通告消息中还包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；
所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口；或者，
所述端口类型包括：基于TCP消息摘要算法第五版MD5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口。
本发明实施例提供的确定路径计算单元的方法和通信设备，PCC接收携带PCE的位置信息和传输能力信息的路由通告消息，根据PCE的传输能力信息和预设选取策略，选取满足PCC传输能力的PCE用于路径计算，可以更有效地建立PCEP会话，进而提高PCC提交路径计算请求和获得路径计算结果的效率和成功率。
附图说明
图1为本发明实施例提供的一种通告传输能力的方法流程图；
图2a为本发明实施例提供的OSPF PCED TLV或IS-IS PCED sub-TLV的格式示意图；
图2b为本发明实施例提供的携带端口信息的sub-TLV的格式示意图；
图3为本发明实施例提供的另一种通告传输能力的方法流程图；
图4为本发明实施例提供的一种确定路径计算单元的方法流程图；
图5为本发明实施例提供的一种通告传输能力和确定路径计算单元的方法流程图；
图6为本发明实施例提供的另一种通告传输能力和确定路径计算单元的方法流程图；
图7为本发明实施例提供的再一种通告传输能力和确定路径计算单元的方法流程图；
图8为本发明实施例提供的一种通信设备的结构框图；
图9为本发明实施例提供的另一种通信设备的结构框图；
图10为本发明实施例提供的又一种通信设备的结构框图；
图11为本发明实施例提供的一种通信设备的结构示意图；
图12为本发明实施例提供的另一种通信设备的结构示意图；
图13为本发明实施例提供的又一种通信设备的结构示意图。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
为便于对本发明实时的理解，下面将结合附图以具体实施例做进一步的解释说明，实施例并不构成对本发明实施例的限定。
由于存在各种传输协议，如果PCC和PCE之间没有预先配置或者协商好传输协议信息，有可能导致PCC和PCE建立PCEP会话失败，PCC无法向PCE提交 路径计算请求并获得路径计算结果。PCC需要等待新的路由通告消息，例如OSPF链路状态(link state advertisement，简称LSA)，来获得满足自己的路径计算请求且支持TLS的PCE，才能成功建立PCEP会话，进而提交路径计算请求并获得路径计算结果。这样，PCC可能要经过多次失败才能成功建立PCEP会话以获得路径计算结果，因此降低了网络中路径计算的效率。为此本发明提供了向PCC发送携带PCE传输能力的路由通告消息，以使PCC根据路由通告消息中的PCE传输能力确定用于路径计算的PCE的技术方案。
接下来将详细介绍本发明技术方案。
如图1所示，本发明实施例提供了一种通告传输能力的方法，包括：
101、通信设备生成IGP路由通告消息，所述IGP路由通告消息中包括第一路径计算单元PCE的位置信息和传输能力信息；
所述第一PCE的传输能力信息包括第一标志位、第二标志位和第三标志位；其中，所述第一标志位用于指示所述第一PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项(英文：PCEP over TCP MD5)；所述第二标志位用于指示所述第一PCE是否支持TCP认证配置选项AO(英文：PCEP over TCP AO)；所述第三标志位用于指示所述第一PCE是否支持传输层安全TLS(英文：PCEP over TLS)。
可以理解的是，如果所述第二标志位指示所述第一PCE支持TCP AO，且所述第三标志位指示所述第一PCE支持TLS，则所述第二标志位和所述第三标志位结合起来指示所述第一PCE支持TLS和TCP AO(英文：PCEP over TLS and TCP AO)。当然，可选地，所述第一PCE的传输能力信息还包括第四标志位，所述第四标志位用于指示所述第一PCE是否支持TLS和TCP AO。
进一步地，所述路由通告消息中还可以包括所述第一PCE的端口信息，所述端口信息包括端口类型和端口号。所述端口类型包括：基于TCP的PCEP(英文：PCEP over TCP)端口，基于TLS的PCEP(英文：PCEP over TLS)端口。或者，所述端口类型包括：基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5) 端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，基于TLS的PCEP(英文：PCEP over TLS)端口；进一步可选地，如果所述第一PCE的传输能力信息还包括第四标志位，相应地所述端口类型包括：基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
102、向所述通信设备所在域发送所述IGP路由通告消息。
所述通信设备向所述通信设备所在域发送所述IGP路由通告消息，通常也可以说泛洪(英文：flood)所述IGP路由通告消息，以向所述通信设备所在域内成员通告所述第一PCE的传输能力。
本实施例中，所述通信设备为IGP路由器，所述通信设备所在域为IGP域；具体地，IGP包括OSPF，IS-IS；相应地，所述通信设备为OSPF路由器，所述通信设备所在域为OSPF域，所述IGP路由通告消息为OSPF LSA；或者，所述通信设备为IS-IS路由器，所述通信设备所在域为IS-IS域，所述IGP路由通告消息为IS-IS LSA。
当PCC和PCE在一个路由域中，支持同一个内部网关协议(interior gateway protocol，简称IGP)，例如开放式最短路径优先(open shortest path first，简称OSPF)协议或中间系统到中间系统(intermediate system to intermediate system，简称IS-IS)协议时，通过OSPF协议或IS-IS协议可以实现PCE的动态发现；具体地，
OSPF协议：沿用OSPF协议的泛洪机制，通过PCE发现(PCED)类型长度值(type length value，简称TLV)，用于将PCE信息通过OSPF控制消息，例如链路状态通告LSA，泛洪到整个OSPF域内成员，以通知PCE相关信息，包括PCE的位置、PCE路径计算的范围、相邻PCE、通信能力和路径计算能力等。
IS-IS协议：通过PCED子TLV(sub-TLV)，用于将PCE信息通过IS-IS控制消息中，例如LSA，泛洪到整个IS-IS域内成员，以通知PCE相关信息，包括PCE的位置、PCE路径计算的范围、相邻PCE、通信能力和路径计算能力等。
其中，PCE路径计算的范围可以包括IS-IS域内、IS-IS域间、自治系统 (autonomous system，简称AS)间、跨网络层等。
所述第一PCE的位置信息，例如网际协议第四版(Internet protocol version 4，简称IPv4)地址或网际协议第六版(Internet protocol version 6，简称IPv6)地址，可以携带在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中的PCE地址(PCE-ADDRESS)sub-TLV中。本发明实施例，PCE的传输能力信息可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，在PCE能力标志(PCE-CAP-FLAGS)sub-TLV中定义三个目前未使用的标志位，作为上述的第一标志位、第二标志位和第三标志位，分别用于指示所述第一PCE是否支持TCP MD5选项，所述第一PCE是否支持TCP AO，所述第一PCE是否支持TLS；进一步地，还可以定义第四标志位，用于指示所述所述第一PCE是否支持TLS和TCP AO。
OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV的格式可以如图2a所示。具体地，图2a中在PCE-ADDRESS sub-TLV中扩展的四个标志位和PCE能力描述的对应关系可以如下：
标志位(bits) 能力描述(capability description)
12 指示是否支持TCP MD5(PCEP over TCP MD5)
13 指示是否支持TCP AO(PCEP over TCP AO)
14 指示是否支持TLS(PCEP over TLS)
15 指示是否支持TLS和TCP AO(PCEP over TLS and TCP AO)
需要说明的是，图2a中以定义四个标志位12,13,14和15作为示例，上述各标志位及对应的能力描述也仅作为示例，并不构成对本发明的限定。
本发明实施例，通过扩展OSPF协议或IS-IS协议的PCE能力发现，可以实现PCE传输能力的通告，从而使得PCC可以选取与自身传输能力匹配的PCE，提高PCC提交路径计算请求和获得路径计算结果的效率和成功率。
进一步地，还可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV， 定义携带所述第一PCE的端口信息的sub-TLV，格式可以如图2b所示。可以有两种实现方式携带所述第一PCE的端口信息：
一种是定义两个sub-TLV携带PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述第一PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述第一PCE的传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
具体以PCE-ADDRESS sub-TLV中扩展四个标志位用于支持PCE的传输能力为例，在定义四个sub-TLV分别携带上述四种传输能力各自对应的端口的情况下，
若PCE-CAP-FLAGS sub-TLV中所述第一标志位指示PCE支持TCP MD5选项，在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TCP MD5端口sub-TLV；
若PCE-CAP-FLAGS sub-TLV中所述第二标志位指示PCE支持TCP AO，在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TCP AO端口的sub-TLV；
若PCE-CAP-FLAGS sub-TLV中所述第三标志位指示PCE支持TLS，在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TLS端口的sub-TLV；
若PCE-CAP-FLAGS sub-TLV中所述第四标志位指示PCE支持TLS和TCP AO， 在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TLS and TCP AO端口的sub-TLV。
在定义两个sub-TLV分别携带支持TCP或TLS传输能力对应的端口的情况下，
若PCE-CAP-FLAGS sub-TLV中所述第一标志位指示PCE支持TCP MD5选项，或者所述第二标志位指示PCE支持TCP AO，或者所述第一标志位指示PCE支持TCP MD5选项且所述第二标志位指示PCE支持TCP AO，在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TCP端口sub-TLV；
若PCE-CAP-FLAGS sub-TLV中所述第三标志位指示PCE支持TLS，或者第四标志位指示PCE支持TLS和TCP AO，或者第三标志位指示PCE支持TLS且第四标志位指示PCE支持TLS和TCP AO，在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TLS端口的sub-TLV。
进一步地，在生成所述路由通告消息之前，所述方法还可以包括：所述通信设备接收所述第一PCE的注册信息，所述注册信息中包括所述第一PCE的传输能力。所述注册信息还包括PCE路径计算的范围、相邻PCE、通信能力和路径计算能力等。
进一步地，所述路由通告消息还可以包括第二PCE的位置信息和传输能力信息；可选地，还包括所述第二PCE的端口信息。相应地，在生成所述路由通告消息之前，所述方法还可以包括：所述通信设备接收所述第二PCE的注册信息，所述注册信息中包括所述第二PCE的传输能力。
本发明实施例提供的通告传输能力的方法，通过扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义标志位指示PCE的传输能力，从而可以基于OSPF协议或IS-IS协议实现PCE传输能力的通告，使得PCC可以选取与自身传输能力匹配的PCE，保证PCC与PCE间有效地建立PCEP会话，从而提高PCC与PCE间路径计算的效率和成功率；进一步地，通过定义新的sub-TLV来携带传输能力对应的端口信息，这样当PCC不知道PCE用于建立PCEP会话的端口时， 可以直接从OSPF LSA或IS-IS LSA中获取，进一步保证了PCC与PCE间有效地建立PCEP会话。
进一步地，在上述图1所示方法的基础上，如图3所示，本发明实施例提供了另一种通告传输能力的方法，包括：
301、边界网关协议(border gateway protocol，简称BGP)路由器接收来自自治系统AS域的至少一个IGP路由通告消息，所述IGP路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；
所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP摘要算法5选项；所述第二标志位用于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；可选地，所述PCE的传输能力信息还包括第四标志位，用于指示所述PCE是否支持TLS和TCP AO；
所述IGP路由通告消息为OSPF LSA或者IS-IS LSA。
所述BGP路由器具体可以为BGP发言者(英文：speaker)。
具体实现中，可以在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV的PCE-CAP-FLAGS sub-TLV中定义三个目前未使用的标志位，作为上述的第一标志位、第二标志位和第三标志位，分别用于指示所述第一PCE是否支持TCP MD5选项，所述第一PCE是否支持TCP AO，所述第一PCE是否支持TLS；进一步地，还可以定义第四标志位，用于指示所述所述第一PCE是否支持TLS和TCP AO；具体可以参考本发明图1所示方法中所述，在此不再赘述。这样，基于扩展的OSPF协议或IS-IS协议的PCE能力发现，可以实现PCE传输能力的通告。
302、根据所述至少一个IGP路由通告消息生成边界网关协议BGP路由通告消息，所述BGP路由通告消息中包括所述至少一个IGP路由通告消息中的PCE的位置信息和传输能力信息；
举例来说，假设BGP路由器收到两个IGP路由通告消息：第一IGP路由通 告消息和第二IGP路由通告消息，第一IGP路由通告消息中包括第一PCE的位置信息和传输能力信息，第二路由通告消息中包括第二PCE的位置信息和传输能力信息，第一IGP路由通告消息与第二IGP路由通告消息来自一个AS域；则所述BGP路由器根据所述第一路由通告消息和所述第二路由通告消息生成所述BGP路由通告消息，所述BGP路由通告消息中包括第一PCE的位置信息和传输能力信息，以及第二PCE的位置信息和传输能力信息。
本发明实施例中，BGP路由器可以仅根据一个IGP路由通告消息生成一个BGP路由通告消息，也可以根据一个AS域收到的多个IGP路由通告消息生成一个BGP路由通告消息，将多个IGP路由通告消息中携带的各个PCE的位置信息和传输能力信息通过一个BGP路由通告消息发送到其他AS域。
可选地，所述BGP路由器收到一个IGP路由通告消息后，还包括：检查所述IGP路由通告消息中是否包含PCE的传输能力信息；如果包含PCE的传输能力信息，则生成包含所述PCE的位置信息和传输能力信息的BGP路由通告消息；如果没有包含PCE的传输能力信息，则按照现有标准规范进行处理。
具体实现中，可以扩展BGP协议，在BGP协议的网络层可达信息(network layer reachability information，简称NLRI)TLV中，定义PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV，携带在BGP路由通告消息中。其中，PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV的格式可以同上述扩展的OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，如图2a所示。可选地，PCE的传输能力信息也可以通过扩展BGP协议的能力选项参数(英文：capability optional parameter)，定义目前未使用的能力编码，用于标识PCE的传输能力；具体地，定义三个能力编码，分别用于标识是否支持TCP MD5选项，是否支持TCP AO，是否支持TLS；进一步，还可以定义一个能力编码，用于标识是否支持TLS和TCP AO。
进一步地，所述IGP路由通告消息中还可以包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；所述端口类型包括：基于TCP的PCEP(英 文：PCEP over TCP)端口，基于TLS的PCEP(英文：PCEP over TLS)端口。或者，所述端口类型包括：基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，基于TLS的PCEP(英文：PCEP over TLS)端口；进一步地，还可以包括基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。具体实现中，可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述第一PCE的端口信息的sub-TLV，格式可以如图2b所示，具体可参考本发明图1所示方法中所述，在此不再赘述。
则相应地，所述BGP路由通告消息中还可以包括所述PCE的端口信息。具体实现中，可以扩展BGP协议，例如，在NLRI中定义携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。类似于对OSPF协议或IS-IS协议的扩展，同样可以有两种实现方式携带所述PCE的端口信息：
一种是定义两个sub-TLV携带PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述第一PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述第一PCE的传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
303、将所述BGP路由通告消息发送到接收所述AS域以外的AS域。
具体地，假设所述至少一个IGP路由通告消息来自第一AS，所述BGP路由器位于所述第一AS和第二AS边界上，则将所述BGP路由通告消息发送到所述 第二AS，以向所述第二AS内成员通告所述第一PCE的传输能力。
可以理解的是，如本发明图1所示方法中所述，所述IGP路由通告消息中可以仅包括一个PCE的位置信息和传输能力信息，也可以包括多个PCE的位置信息和传输能力信息。则相应地，所述BGP路由通告消息中包括所述IGP路由通告消息中的多个PCE的位置信息和传输能力信息。
本发明实施例提供的通告传输能力的方法，BGP路由器通过扩展的BGP协议，实现AS间PCE传输能力的通告，可以保证PCC跨AS与PCE有效建立PCEP会话，从而提高PCC与PCE间路径计算的效率和成功率。
进一步地，在上述图1和图3所示方法的基础上，如图4所示，本发明实施例提供了一种确定路径计算单元的方法，包括：
401、PCC接收至少一个路由通告消息，所述路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；
所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持TCP MD5选项；所述第二标志位用于指示所述PCE是否支持TCP AO；所述第三标志位用于指示所述PCE是否支持TLS。
可选地，当标志位为0时，表示不支持；当标志位为1时，表示支持；例如，所述路由通告消息中，第一标志位为1，表示所述PCE支持TCP MD5；第二标志位为0，表示所述PCE不支持TCP AO；第三标志位为1，表示所述PCE支持TLS。
可以理解的是，如果所述第二标志位指示所述PCE支持TCP AO，且所述第三标志位指示所述PCE支持TLS，则所述第二标志位和所述第三标志位结合起来指示所述PCE支持TLS和TCP AO(英文：PCEP over TLS and TCP AO)。当然，可选地，所述PCE的传输能力信息还包括第四标志位，所述第四标志位用于指示所述PCE是否支持TLS和TCP AO。
可选地，所述路由通告消息中还包括所述PCE的端口信息，所述端口信息包括端口类型和端口号。所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口。或者，所述端口类型包括：基于TCP摘要算法5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口；进一步可选地，如果所述PCE的传输能力信息还包括第四标志位，相应地所述端口类型包括：基于TLS和TCP AO的PCEP端口。
所述路由通告消息可以为IGP路由通告消息(具体可参考本发明图1所示的方法中所述)或BGP路由通告消息(具体可参考本发明图3所示的方法中所述)。其中，
所述IGP路由通告消息可以为OSPF LSA或IS-IS LSA；具体实现中，所述PCE的位置信息，例如IPv4地址或IPv6地址，可以携带在OSPF LSA的PCED TLV或IS-IS LSA的PCED sub-TLV中的PCE-ADDRESS sub-TLV中；所述PCE的传输能力信息可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，在PCE-CAP-FLAGS sub-TLV中定义三个目前未使用的标志位分别作为上述的第一标志位、第二标志位和第三标志位；进一步地，还可以定义第四标志位。OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV的具体格式可以如图2a所示。具体地，图2a中PCE-ADDRESS sub-TLV中扩展的四个标志位和PCE能力描述的对应关系可以如下：
标志位(bits) 能力描述(capability description)
12 指示是否支持TCP MD5(PCEP over TCP MD5)
13 指示是否支持TCP AO(PCEP over TCP AO)
14 指示是否支持TLS(PCEP over TLS)
15 指示是否支持TLS和TCP AO(PCEP over TLS and TCP AO)
需要说明的是，图2a中以定义四个标志位12,13,14和15作为示例，上述各标志位对应的能力描述也仅作为示例，并不构成对本发明的限定。
本发明实施例，通过扩展OSPF协议或IS-IS协议的PCE能力发现，实现PCE 传输能力的通告。PCC接收携带PCE传输能力信息的路由通告消息，并选取与自身传输能力匹配的PCE，可以保证PCC与PCE间有效建立PCEP会话，进而提高PCC与PCE间提交路径计算请求和获得路径计算结果的效率和成功率。
进一步地，还可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。还可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。可以有两种实现方式携带所述第一PCE的端口信息：
一种是定义两个sub-TLV携带PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述PCE的传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
具体以PCE-ADDRESS sub-TLV中扩展四个标志位用于支持PCE的传输能力为例，在定义四个sub-TLV分别携带上述四种传输能力各自对应的端口的情况下，
若PCE-CAP-FLAGS sub-TLV中所述第一标志位指示PCE支持TCP MD5选项，在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TCP MD5端口sub-TLV；
若PCE-CAP-FLAGS sub-TLV中所述第二标志位指示PCE支持TCP AO，在OSPF 协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TCP AO端口的sub-TLV；
若PCE-CAP-FLAGS sub-TLV中所述第三标志位指示PCE支持TLS，在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TLS端口的sub-TLV；
若PCE-CAP-FLAGS sub-TLV中所述第四标志位指示PCE支持TLS和TCP AO，在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TLS and TCP AO端口的sub-TLV。
在定义两个sub-TLV分别携带支持TCP或TLS传输能力对应的端口的情况下，
若PCE-CAP-FLAGS sub-TLV中所述第一标志位指示PCE支持TCP MD5选项，或者所述第二标志位指示PCE支持TCP AO，或者所述第一标志位指示PCE支持TCP MD5选项且所述第二标志位指示PCE支持TCP AO，在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TCP端口sub-TLV；
若PCE-CAP-FLAGS sub-TLV中所述第三标志位指示PCE支持TLS，或者第四标志位指示PCE支持TLS和TCP AO，或者第三标志位指示PCE支持TLS且第四标志位指示PCE支持TLS和TCP AO，在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中携带PCEP over TLS端口的sub-TLV。
所述BGP路由通告消息中包括所述PCE的位置信息和传输能力信息，具体实现中，可以通过扩展BGP协议来实现，例如，在BGP协议的NLRI TLV中，定义PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV携带在BGP路由通告消息中，其中PCE-ADDRESS sub-TLV用于携带所述PCE的位置信息，PCE-CAP-FLAGS sub-TLV用于携带所述PCE的传输能力信息，具体格式可以同上述扩展的OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，如图2a所示。
进一步地，所述BGP路由通告消息中还可以包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；与所述IGP路由通告消息相应地，所述端 口类型包括：PCEP over TCP端口，PCEP over TLS端口；或者，所述端口类型包括：PCEP over TCP MD5端口，基PCEP over TCP AO端口，PCEP over TLS端口；进一步地，还可以包括PCEP over TLS and TCP AO端口。具体实现中，可以扩展BGP协议，例如，在NLRI中携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。与对OSPF协议或IS-IS协议的扩展相应地，同样可以有两种实现方式携带所述PCE的端口信息：
一种是定义两个sub-TLV携带所述PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述PCE的传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
402、所述PCC根据预设选取策略和所述至少一个路由通告消息中PCE的传输能力信息，确定用于路径计算的PCE。
所述预设选取策略包括：
选取具备所述PCC支持的传输能力的PCE用于路径计算。例如，所述PCC支持TCP MD5，根据所述PCE的传输能力信息，所述PCE支持TCP MD5，还支持TLS，则所述PCE具备所述PCC支持的传输能力，那么根据预设选取策略和所述第一PCE的传输能力信息，所述PCC确定所述PCE用于路径计算。进一步地，所述预设选取策略也可以为：结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个具备所述PCC支持的传输能力的PCE用于路径计算；具体的， 以结合PCE的优先级为例，所述预设选取策略包括：若仅有一个PCE具备所述PCC支持的传输能力，则选取该PCE用于路径计算；若多个PCE具备所述PCC支持的传输能力，选取所述多个PCE中优先级较高的PCE用于路径计算。
可以理解的是，本发明实施例中，所述路由通告消息中可以仅包括一个PCE的位置信息和传输能力信息；也可以包括多个PCE的位置信息和传输能力信息。所述PCC可以根据一个路由通告消息中的一个或多个PCE的传输能力信息，也可以根据多个路由通告消息中所有PCE的传输能力信息来确定用于路径计算的PCE。
举例来说，PCC收到第一路由通告消息和第二路由通告消息，所述第一路由通告消息中包括第一PCE的位置信息和传输能力信息，第二PCE的位置信息和传输能力信息，所述第二路由通告消息中包括第三PCE的位置信息和传输能力信息。
例如，场景一：PCC1支持TCP MD5，根据所述第一PCE的传输能力信息，所述第一PCE支持TCP MD5，还支持TLS；根据所述第二PCE的传输能力信息，所述第二PCE支持TCP MD5，还支持TCP AO；根据所述第三PCE的传输能力信息，所述第三PCE支持TLS和TCP AO。
则在场景一的情况下，根据预设选取策略和所述第一PCE的传输能力信息、所述第二PCE的传输能力信息、所述第三PCE的传输能力信息，所述第一PCE和所述第二PCE都具备PCC1支持的传输能力，所述第三PCE不具备PCC1支持的传输能力，那么PCC1确定所述第一PCE或所述第二PCE用于路径计算，也可以确定所述第一PCE和所述第二PCE用于路径计算，而不会选取所述第三PCE用于路径计算。可选地，PCC1进一步根据所述第一PCE的优先级和所述第二PCE的优先级，确定优先级较高的所述第二PCE用于路径计算。
或者，所述预设选取策略包括：若所述PCC既支持TCP AO也支持TCP MD5，则优先选取支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，选取支持TCP MD5的PCE用于路径计算。进一步地，还可以结合PCE 的优先级或PCE的负载信息或所述PCC的喜好，选取一个PCE用于路径计算，则所述预设选取策略包括：若所述PCC既支持TCP AO也支持TCP MD5，则结合PCE的优先级或PCE的负载信息或所述PCC的喜好，优先选取一个支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个支持TCP MD5的PCE用于路径计算。以结合PCE的优先级为例，所述预设选取策略包括：若所述PCC既支持TCP AO也支持TCP MD5，如果多个PCE支持TCP AO，选取优先级较高的PCE用于路径计算；如果仅有一个PCE支持TCP AO，则确定该PCE用于路径计算；如果任何一个PCE都不支持TCP AO，则若多个PCE支持TCP MD5，选取优先级较高的PCE用于路径计算，若仅有一个PCE支持TCP MD5，确定该PCE用于路径计算。
例如，场景二：PCC2支持TCP AO且支持TCP MD5，根据所述第一PCE的传输能力信息，所述第一PCE支持TCP MD5，还支持TLS；根据所述第二PCE的传输能力信息，所述第二PCE支持TCP MD5，还支持TCP AO；根据所述第三PCE的传输能力信息，所述第三PCE支持TLS和TCP AO。
则在场景二的情况下，根据预设选取策略和所述第一PCE的传输能力信息、所述第二PCE的传输能力信息、所述第三PCE的传输能力信息，所述第二PCE和所述第三PCE都支持TCP AO，那么PCC2确定所述第二PCE或所述第三PCE用于路径计算，也可以确定所述第二PCE和所述第三PCE用于路径计算，而不会选取所述第一PCE用于路径计算。可选地，PCC2进一步根据所述第二PCE的优先级和所述第三PCE的优先级，确定优先级较高的所述第二PCE用于路径计算。
或者，所述预设选取策略包括：若所述PCC支持TLS和TCP AO，则根据安全性需求确定用于路径计算的PCE；所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全。则所述预设选取策略具体来说包括：若所述PCC支持TLS和TCP AO，当安全性需求为传输层及敏感数据安全时，选取支持TLS和TCP AO的PCE用于路径计算；当安全性需求为传输层时，选取支持TCP AO 的PCE用于路径计算；当安全性需求为敏感数据安全时，选取支持TLS的PCE用于路径计算。进一步地，还可以结合PCE的优先级，确定一个PCE用于路径计算，则所述预设选取策略包括：若所述PCC支持TLS和TCP AO，则根据安全性需求，结合PCE的优先级或PCE的负载信息或所述PCC的喜好，确定一个用于路径计算的PCE；具体地，所述预设选取策略包括：若所述PCC支持TLS和TCP AO，当多个PCE满足所述安全性需求时，可以根据所述多个PCE的优先级或所述多个PCE的负载信息或所述PCC的喜好，选取优先级较高的PCE用于路径计算；当仅有一个PCE满足所述安全性需求时，确定该PCE用于路径计算。
例如，场景三：PCC3支持TLS和TCP AO，根据所述第一PCE的传输能力信息，所述第一PCE支持TCP MD5，还支持TLS；根据所述第二PCE的传输能力信息，所述第二PCE支持TCP MD5，还支持TCP AO；根据所述第三PCE的传输能力信息，所述第三PCE支持TLS和TCP AO。
则在场景三的情况下，
当安全性需求为传输层及敏感数据安全时，根据预设选取策略和所述第一PCE的传输能力信息、所述第二PCE的传输能力信息、所述第三PCE的传输能力信息，所述第三PCE支持TLS和TCP AO，那么PCC3确定所述第三PCE的优先级用于路径计算，而不会选取所述第一PCE或所述二PCE用于路径计算。
当安全性需求为敏感数据安全时，根据预设选取策略和所述第一PCE的传输能力信息、所述第二PCE的传输能力信息、所述第三PCE的传输能力信息，所述第一PCE和所述第三PCE都支持TLS，那么PCC3确定所述第一PCE或所述第三PCE用于路径计算；也可以确定所述第一PCE和所述第三PCE用于路径计算，而不会选取所述二PCE用于路径计算。可选地，PCC3进一步根据所述第一PCE的优先级和所述第三PCE的优先级，确定优先级较高的所述第一PCE用于路径计算。
当安全性需求为传输层安全时，根据预设选取策略和所述第一PCE的传输能力信息、所述第二PCE的传输能力信息、所述第三PCE的传输能力信息，所 述第二PCE和所述第三PCE都支持TCP AO，那么PCC3确定所述第二PCE或所述第三PCE用于路径计算；也可以确定所述第二PCE和所述第三PCE用于路径计算，而不会选取所述第一PCE用于路径计算。可选地，PCC3进一步根据所述第二PCE的优先级和所述第三PCE的优先级，确定优先级较高的所述第二PCE用于路径计算。
可选地，所述安全性需求还可以根据所述PCC的偏好(英文：preference)进行设置，例如，传输层及敏感数据安全，优先于传输层安全，传输层安全优先于敏感数据安全，则所述预设选取策略具体来说包括：若所述PCC支持TLS和TCP AO，优先选取支持TLS和TCP AO的PCE用于路径计算；在任何一个PCE都不支持TLS和TCP AO的情况下，优先选取支持TCP AO的PCE用于路径计算；在任何一个PCE都不支持TCP AO的情况下，则选取支持TLS的PCE用于路径计算。
具体实现中，所述PCE的优先级信息可以携带在OSPF协议的PCED TLV或者IS-IS协议的PCED sub-TLV。本发明实施例中，上述举例以所述第二PCE的优先级高于所述第一PCE的优先级，所述第一PCE的优先级高于所述第三PCE的优先级作为示例来说明，不构成对本发明的限定。
可选地，所述PCE负载信息包括PCE的负荷能力、当前负载情况等。当结合PCE的负载信息选取用于路径计算的PCE时，例如可以选择负荷能力强，当前负载较小的PCE用于路径计算。当然，所述预设选取策略也可以结合PCC的本地策略，例如本地策略为选取支持传输能力最多的PCE；当然PCC的本地策略可以静态配置，也可以根据需求动态调整。
需要说明的是，对于PCC按照本发明技术方案选取PCE之后，与PCE建立PCEP会话、提交路径计算请求和获取路径计算结果等，可参考目前标准规范，本发明实施例在此不再赘述。
本发明实施例提供的确定路径计算单元的方法，PCC接收携带PCE传输能力信息的路由通告消息，并根据PCE的传输能力和预设选取策略，选择与自身传 输能力匹配的PCE用于路径计算，可以保证PCC与PCE间有效建立PCEP会话，从而提高PCC与PCE间路径计算的成功率和效率。
以下将结合具体应用场景，在上述图1，图3和图4所述方法基础上，介绍本发明提供的通告传输能力和确定路径计算单元的方法。
假设OSPF域内，PCC支持TLS，PCE1支持TLS，PCE2支持TCP AO，PCE3支持TCP MD5和TCP AO。预设选取策略为：若PCE具备PCC支持的传输能力，选择优先级较高的PCE用于路径计算。参见图5，为本发明实施例提供的一种通告传输能力和确定路径计算单元的方法流程图，包括如下步骤：
501、路由器1生成路由通告消息1，向路由器1所在域发送该路由通告消息1；该路由通告消息1中携带PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV，其中，PCE-ADDRESS sub-TLV中携带PCE1的位置，PCE-CAP-FLAGS sub-TLV指示PCE1支持TLS；
502、PCC接收所述路由通告消息1；
503、路由器2生成路由通告消息2并在域内广播，路由通告消息2中携带PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV，其中，PCE-ADDRESS sub-TLV中携带PCE2的位置，PCE-CAP-FLAGS sub-TLV指示PCE2支持TCP AO；
504、PCC接收所述路由通告消息2；
505、路由器3生成路由通告消息3并在域内广播，路由通告消息3中携带PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV，其中，PCE-ADDRESS sub-TLV中携带PCE3的位置，PCE-CAP-FLAGS sub-TLV指示PCE3支持TCP MD5和TCP AO；
506、PCC接收所述路由通告消息3；
需要说明的是，对501-502,与503-504，及505-506之间的时间先后不作限定，505-506可能发生在501-502，也可能发生在501-502之后503-504之前；当然501-502,503-504和505-506也可以同时发生。
507、PCC根据PCE1的传输能力信息、PCE2的传输能力信息、PCE3的传输能力信息和预设选取策略，确定PCE1用于路径计算的PCE。
PCC选定PCE1之后，与PCE1之间建立TLS连接，然后建立PCEP会话，提交路径计算请求，获取路径计算结果。
假设IS-IS域内，PCC支持TCP AO和TCP MD5，PCE1支持TCP MD5，PCE2支持TLS，PCE3支持TLS和TCP MD5，PCE1的优先级高于PCE2的优先级，PCE2的优先级高于PCE3的优先级；预设选取策略为：若所述PCC既支持TCP AO也支持TCP MD5，如果多个PCE支持TCP AO，选择优先级较高的PCE用于路径计算；如果仅有一个PCE支持TCP AO，则确定该PCE用于路径计算；如果任何一个PCE都不支持TCP AO，则若多个PCE支持TCP MD5，选择优先级较高的PCE用于路径计算，若仅有一个PCE支持TCP MD5，确定该PCE用于路径计算。参见图6，为本发明实施例提供的另一种通告传输能力和确定路径计算单元的方法流程图，包括如下步骤：
601、路由器1生成路由通告消息1并在域内广播，路由通告消息1中携带PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV，其中，PCE-ADDRESS sub-TLV中携带PCE1的位置，PCE-CAP-FLAGS sub-TLV指示PCE1支持TCP MD5；
602、PCC接收所述路由通告消息1；
603、路由器2生成路由通告消息2并在域内广播，路由通告消息2中携带PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV，其中，PCE-ADDRESS sub-TLV中携带PCE2的位置，PCE-CAP-FLAGS sub-TLV指示PCE2支持TLS；
604、PCC接收所述路由通告消息2；
605、路由器3生成路由通告消息3并在域内广播，路由通告消息3中携带PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV，其中，PCE-ADDRESS sub-TLV中携带PCE3的位置，PCE-CAP-FLAGS sub-TLV指示PCE3支持TLS和TCP MD5；
606、PCC接收所述路由通告消息3；
需要说明的是，对601-602,与603-604，及605-606之间的时间先后不作限定，605-606可能发生在601-602，也可能发生在601-602之后603-604之前； 当然601-602,603-604和605-606也可以同时发生。
607、PCC根据PCE1的传输能力信息、PCE2的传输能力信息、PCE3的传输能力信息和预设选取策略，确定PCE1用于路径计算的PCE。
PCC支持TCP AO和TCP MD5，而PCE1、PCE2和PCE3均不支持TCP AO；PCE1和PCE3都支持TCP MD5，而PCE1的优先级高于PCE3，因此PCC选取PCE1用于路径计算。
PCC选定PCE1之后，与PCE1之间建立TLS连接，然后建立PCEP会话，提交路径计算请求，获取路径计算结果。
假设OSPF域内，PCC支持TLS和TCP AO，PCE1支持TCP MD5，还支持TLS；PCE2支持TCP MD5，还支持TCP AO；PC3支持TLS和TCP AO。所述预设选取策略包括：若所述PCC支持TLS和TCP AO，则根据安全性需求确定用于路径计算的PCE。参见图7，为本发明实施例提供的再一种通告传输能力和确定路径计算单元的方法流程图，包括如下步骤：
701、路由器1生成路由通告消息1并在域内广播，路由通告消息1中携带PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV，其中，PCE-ADDRESS sub-TLV中携带PCE1的位置，PCE-CAP-FLAGS sub-TLV指示PCE1支持TCP MD5和TLS；
702、PCC接收所述路由通告消息1；
703、路由器2生成路由通告消息2并在域内广播，路由通告消息2中携带PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV，其中，PCE-ADDRESS sub-TLV中携带PCE2的位置，PCE-CAP-FLAGS sub-TLV指示PCE2支持TCP MD5和TCP AO；
704、PCC接收所述路由通告消息2；
705、路由器3生成路由通告消息3并在域内广播，路由通告消息3中携带PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV，其中，PCE-ADDRESS sub-TLV中携带PCE3的位置，PCE-CAP-FLAGS sub-TLV指示PCE3支持TLS和TCP AO；
706、PCC接收所述路由通告消息3；
需要说明的是，对701-702,与703-704，及705-706之间的时间先后不作限定，705-706可能发生在701-702，也可能发生在701-702之后703-704之前；当然701-702,703-704和705-706也可以同时发生。
707、PCC根据PCE1的传输能力信息、PCE2的传输能力信息、PCE3的传输能力信息和预设选取策略，确定用于路径计算的PCE。
具体地，若安全性需求为传输层及敏感数据安全，PCC根据PCE1的传输能力信息、PCE2的传输能力信息、PCE3的传输能力信息和预设选取策略，确定PCE3用于路径计算。PCC选定PCE3之后，与PCE3之间建立TLS and TCP AO连接，然后建立PCEP会话，即建立PCEP over TLS and TCP AO，提交路径计算请求，获取路径计算结果。
若安全性需求为敏感数据安全，PCC根据PCE1的传输能力信息、PCE2的传输能力信息、PCE3的传输能力信息和预设选取策略，PCE1和PCE3都支持TLS,PCC根据PCE1和PCE3的优先级，确定PCE1用于路径计算。PCC选定PCE1之后，与PCE1之间建立TLS连接，然后建立PCEP会话，即建立PCEP over TLS，提交路径计算请求，获取路径计算结果。
若安全性需求为传输层安全，PCC根据PCE1的传输能力信息、PCE2的传输能力信息、PCE3的传输能力信息和预设选取策略，PCE2和PCE3都支持TCP AO,PCC根据PCE2和PCE3的优先级，确定PCE2用于路径计算。PCC选定PCE2之后，与PCE1之间建立TCP AO连接，然后建立PCEP会话，即建立PCEP over TCP AO，提交路径计算请求，获取路径计算结果。
如图8所示，为本发明实施例提供的一种通信设备结构框图，本实施例中所述通信设备具体为PCC网元，用于实现本发明图4所示的方法，所述通信设备包括：接收单元801和确定单元802；其中，
所述接收单元801，用于接收至少一个路由通告消息，所述路由通告消息中包括PCE的位置信息和传输能力信息；所述PCE的传输能力信息包括第一标志 位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP摘要算法5选项；所述第二标志位用于指示所述第一PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS。
可以理解的是，如果所述第二标志位指示所述PCE支持TCP AO，且所述第三标志位指示所述PCE支持TLS，则所述第二标志位和所述第三标志位结合起来指示所述PCE支持TLS和TCP AO(英文：PCEP over TLS and TCP AO)。当然，可选地，所述PCE的传输能力信息还包括第四标志位，所述第四标志位用于指示所述PCE是否支持TLS和TCP AO。
可选地，当标志位为0时，表示不支持；当标志位为1时，表示支持；例如，所述路由通告消息中，第一标志位为1，表示所述PCE支持TCP MD5；第二标志位为0，表示所述PCE不支持TCP AO；第三标志位为1，表示所述PCE支持TLS。
进一步地，所述路由通告消息中还可以包括所述PCE的端口信息，所述端口信息包括端口类型和端口号。所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口。或者，所述端口类型包括：基于TCP摘要算法5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口；可选地，还包括基于TLS和TCP AO的PCEP端口。
所述确定单元802，用于根据预设选取策略和所述至少一个路由通告消息中PCE的传输能力信息，确定用于路径计算的PCE。
所述路由通告消息可以为IGP路由通告消息(具体可参考本发明图1所示的方法中所述)或BGP路由通告消息(具体可参考本发明图3所示的方法中所述)。其中，所述IGP路由通告消息可以为OSPF LSA或IS-IS LSA；具体实现中，所述PCE的位置信息，例如IPv4地址或IPv6地址，可以携带在OSPF LSA的PCEDTLV或IS-IS LSA的PCED sub-TLV中的PCE-ADDRESS sub-TLV中；所述PCE的传输能力信息可以通过扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV， 在PCE-CAP-FLAGS sub-TLV中定义三个目前未使用的标志位分别作为上述的第一标志位、第二标志位和第三标志位；进一步地，还可以定义第四标志位。OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV的具体格式可以如图2a所示。具体地，图2a中PCE-ADDRESS sub-TLV中扩展的四个标志位和PCE能力描述的对应关系可以如下：
标志位(bits) 能力描述(capability description)
12 指示是否支持TCP MD5(PCEP over TCP MD5)
13 指示是否支持TCP AO(PCEP over TCP AO)
14 指示是否支持TLS(PCEP over TLS)
15 指示是否支持TLS和TCP AO(PCEP over TLS and TCP AO)
需要说明的是，图2a中以定义四个标志位12,13,14和15作为示例，上述各标志位对应的能力描述也仅作为示例，并不构成对本发明的限定。
进一步地，所述IGP路由通告消息中还可以包括所述PCE的端口信息，可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。还可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。可以有两种实现方式携带所述第一PCE的端口信息：
一种是定义两个sub-TLV携带PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述PCE的 传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
所述BGP路由通告消息中包括所述PCE的位置信息和传输能力信息，可以通过扩展BGP协议来实现。例如，在BGP协议的NLRI TLV中定义PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV携带在BGP路由通告消息中，其中PCE-ADDRESS sub-TLV用于携带所述PCE的位置信息，PCE-CAP-FLAGS sub-TLV用于携带所述PCE的传输能力信息，具体格式可以同扩展的OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，如图2a所示。
进一步地，所述BGP路由通告消息中还可以包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；与所述IGP路由通告消息相应地，所述端口类型包括：PCEP over TCP端口，PCEP over TLS端口；或者，所述端口类型包括：PCEP over TCP MD5端口，基PCEP over TCP AO端口，PCEP over TLS端口；进一步地，还可以包括PCEP over TLS and TCP AO端口。具体实现中，可以扩展BGP协议，例如，在NLRI中携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。与对OSPF协议或IS-IS协议的扩展相应地，同样可以有两种实现方式携带所述PCE的端口信息：
一种是定义两个sub-TLV携带所述PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述PCE的传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和 TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
可以理解的是，本发明实施例中，所述路由通告消息中可以仅包括一个PCE的位置信息和传输能力信息；也可以包括多个PCE的位置信息和传输能力信息。所述PCC可以根据一个路由通告消息中的一个或多个PCE的传输能力信息，也可以根据多个路由通告消息中所有PCE的传输能力信息来确定用于路径计算的PCE。
所述预设选取策略包括：
选取具备所述PCC支持的传输能力的PCE用于路径计算。
若所述PCC既支持TCP AO也支持TCP MD5，则优先选取支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，选取支持TCP MD5的PCE用于路径计算；
若所述PCC支持TLS和TCP AO，则根据安全性需求确定用于路径计算的PCE；所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全；具体地，若所述PCC支持TLS和TCP AO，当安全性需求为传输层及敏感数据安全时，选取支持TLS和TCP AO的PCE用于路径计算；当安全性需求为传输层时，选取支持TCP AO的PCE用于路径计算；当安全性需求为敏感数据安全时，选取支持TLS的PCE用于路径计算。
进一步地，还可以结合PCE的优先级或PCE的负载信息或所述PCC的喜好，确定一个PCE用于路径计算，则所述预设选取策略包括：
结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个具备所述PCC支持的传输能力的PCE用于路径计算。具体的，以结合PCE的优先级为例，所述预设选取策略包括：若仅有一个PCE具备所述PCC支持的传输能力，则选取该PCE用于路径计算；若多个PCE具备所述PCC支持的传输能力，选取所述多个PCE中优先级较高的PCE用于路径计算；
若所述PCC既支持TCP AO也支持TCP MD5，则结合PCE的优先级或PCE的负载信息或所述PCC的喜好，优先选取支持TCP AO的PCE用于路径计算，在任 何一个PCE都不支持TCP AO的情况下，结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取支持TCP MD5的PCE用于路径计算。具体的，以结合PCE的优先级为例，若所述PCC既支持TCP AO也支持TCP MD5，如果多个PCE支持TCP AO，选择优先级较高的PCE用于路径计算；如果仅有一个PCE支持TCP AO，则确定该PCE用于路径计算；如果任何一个PCE都不支持TCP AO，则若多个PCE支持TCP MD5，选择优先级较高的PCE用于路径计算，若仅有一个PCE支持TCPMD5，确定该PCE用于路径计算；
若所述PCC支持TLS和TCP AO，则根据安全性需求，结合PCE的优先级或PCE的负载信息或所述PCC的喜好，确定一个用于路径计算的PCE。具体地，若所述PCC支持TLS和TCP AO，当多个PCE满足所述安全性需求时，可以根据所述多个PCE的优先级或PCE的负载信息或所述PCC的喜好，选取优先级较高的PCE用于路径计算；当仅有一个PCE满足所述安全性需求时，确定该PCE用于路径计算。
具体实现中，PCE的优先级信息可以参考目前标准规范，携带在OSPF协议的PCED TLV或者IS-IS协议的PCED sub-TLV。
可选地，所述PCE负载信息包括PCE的负荷能力、当前负载情况等。当结合PCE的负载信息选取用于路径计算的PCE时，例如可以选择负荷能力强，当前负载较小的PCE用于路径计算。当然，所述预设选取策略也可以结合PCC的本地策略，例如本地策略为选取支持传输能力最多的PCE；当然PCC的本地策略可以静态配置，也可以根据需求动态调整。
需要说明的是，对于PCC按照本发明技术方案选取PCE之后，与PCE建立PCEP会话、提交路径计算请求和获取路径计算结果等，可参考目前标准规范，本发明实施例在此不再赘述。
本发明实施例提供的PCC，接收携带PCE传输能力信息的路由通告消息，并根据PCE的传输能力和预设选取策略，选择与自身传输能力匹配的PCE用于路径计算，可以提高PCC与PCE间建立PCEP会话的成功率，从而提高路径计算的 效率。
如图9所示，为本发明实施例提供的另一种通信设备结构框图，本实施例中所述通信设备具体为BGP路由器，用于实现本发明图3所示的方法，所述通信设备包括：接收单元901，生成单元902和发送单元903；其中，
所述接收单元901，用于接收来自自治系统AS域的至少一个IGP路由通告消息，所述IGP路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP摘要算法5选项；所述第二标志位用于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；可选地，所述PCE的传输能力信息还包括第四标志位，用于指示所述PCE是否支持TLS和TCP AO；
所述IGP路由通告消息为OSPF LSA或者IS-IS LSA。
所述BGP路由器具体可以为BGP speaker。
具体实现中，所述PCE的传输能力信息可以通过扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV的PCE-CAP-FLAGS sub-TLV实现，在PCE-CAP-FLAGS sub-TLV中定义三个目前未使用的标志位，作为上述的第一标志位、第二标志位和第三标志位，分别用于指示所述第一PCE是否支持TCP MD5选项，所述第一PCE是否支持TCP AO，所述第一PCE是否支持TLS；进一步地，还可以定义第四标志位，用于指示所述所述第一PCE是否支持TLS和TCP AO。
OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV的格式可以如图2a所示。具体地，图2a中在PCE-ADDRESS sub-TLV中扩展的四个标志位和PCE能力描述的对应关系可以如下：
标志位(bits) 能力描述(capability description)
12 指示是否支持TCP MD5(PCEP over TCP MD5)
13 指示是否支持TCP AO(PCEP over TCP AO)
14 指示是否支持TLS(PCEP over TLS)
15 指示是否支持TLS和TCP AO(PCEP over TLS and TCP AO)
需要说明的是，图2a中以定义四个标志位12,13,14和15作为示例，上述各标志位及对应的能力描述也仅作为示例，并不构成对本发明的限定。
所述生成单元902，用于根据所述至少一个IGP路由通告消息生成边界网关协议BGP路由通告消息，所述BGP路由通告消息中包括所述至少一个IGP路由通告消息中的PCE的位置信息和传输能力信息；
举例来说，假设所述通信设备收到两个IGP路由通告消息：第一IGP路由通告消息和第二IGP路由通告消息，第一IGP路由通告消息中包括第一PCE的位置信息和传输能力信息，第二路由通告消息中包括第二PCE的位置信息和传输能力信息，第一IGP路由通告消息与第二IGP路由通告消息来自一个AS域；则所述通信设备根据所述第一路由通告消息和所述第二路由通告消息生成所述BGP路由通告消息，所述BGP路由通告消息中包括第一PCE的位置信息和传输能力信息，以及第二PCE的位置信息和传输能力信息。
本发明实施例中，所述通信设备可以仅根据一个IGP路由通告消息生成一个BGP路由通告消息，也可以根据一个AS域收到的多个IGP路由通告消息生成一个BGP路由通告消息，将多个IGP路由通告消息中携带的各个PCE的位置信息和传输能力信息通过一个BGP路由通告消息发送到其他AS域。
具体实现中，可以扩展BGP协议，例如，在NLRI TLV中，定义PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV携带在BGP路由通告消息中。可选地，PCE的传输能力信息也可以通过扩展BGP协议的能力选项参数(英文：capability optional parameter)，定义目前未使用的能力编码，用于标识PCE的传输能力。具体地对BGP协议的扩展，可参考如本发明图3所示方法中所述，在此不再赘述。
所述发送单元903，用于将所述BGP路由通告消息发送到所述AS以外的自治系统AS域。
假设所述至少一个IGP路由通告消息来自第一AS域，所述BGP路由器位于所述第一AS和第二AS边界上。则所述发送单元903将所述BGP路由通告消息发送到所述第二AS，以向所述第二AS内成员通告所述PCE的传输能力。
进一步地，所述IGP路由通告消息中还可以包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；所述端口类型包括：基于TCP的PCEP(英文：PCEP over TCP)端口，基于TLS的PCEP(英文：PCEP over TLS)端口。或者，所述端口类型包括：基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，基于TLS的PCEP(英文：PCEP over TLS)端口；进一步地，还可以包括基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。具体实现中，可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述第一PCE的端口信息的sub-TLV，格式可以如图2b所示，具体可参考本发明图1所示方法中所述，在此不再赘述。
则相应地，所述BGP路由通告消息中还可以包括所述PCE的端口信息。具体实现中，可以扩展BGP协议，例如，在NLRI中定义携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。类似于对OSPF协议或IS-IS协议的扩展，同样可以有两种实现方式携带所述PCE的端口信息：
一种是定义两个sub-TLV携带PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述第一PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述第一 PCE的传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
可选地，所述通信设备还包括检查单元，用于在所述接收单元901收到所述IGP路由通告消息后，所述生成单元902生成所述BGP路由通告消息之前，检查所述IGP路由通告消息中是否包含PCE的传输能力信息。如果所述检查确定所述IGP路由通告消息中包含PCE的传输能力信息，则所述生成单元902，生成包含所述PCE的位置信息和传输能力信息的BGP路由通告消息；如果所述检查确定所述IGP路由通告消息中没有包含PCE的传输能力信息，则所述通信设备按照现有标准规范进行处理。
可以理解的是，所述IGP路由通告消息中可以仅包括一个PCE的位置信息和传输能力信息，也可以包括多个PCE的位置信息和传输能力信息。则相应地，所述BGP路由通告消息中包括所述IGP路由通告消息中的多个PCE的位置信息和传输能力信息。
本发明实施例提供的通信设备，通过扩展的BGP协议，实现AS间PCE传输能力的通告，可以保证PCC跨AS与PCE有效建立PCEP会话，从而提高PCC与PCE间路径计算的效率和成功率。
如图10所示，为本发明实施例提供的又一种通信设备结构框图，本实施例中所述通信设备具体为IGP路由器，用于实现本发明图1所示的方法，所述通信设备包括：
生成单元1001，用于生成IGP路由通告消息，所述路由通告消息中包括第一PCE的位置信息和传输能力信息；所述第一PCE的传输能力信息包括第一标志位、第二标志位和第三标志位；其中，所述第一标志位用于指示所述第一PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项(英文：PCEP over TCP MD5)；所述第二标志位用于指示所述第一PCE是否支持TCP认证配置选项AO(英文：PCEP over TCP AO)；所述第三标志位用于指示所述第一PCE是否支持传输 层安全TLS(英文：PCEP over TLS)。
可以理解的是，如果所述第二标志位指示所述第一PCE支持TCP AO，且所述第三标志位指示所述第一PCE支持TLS，则所述第二标志位和所述第三标志位结合起来指示所述第一PCE支持TLS和TCP AO(英文：PCEP over TLS and TCP AO)。当然，可选地，所述第一PCE的传输能力信息还包括第四标志位，所述第四标志位用于指示所述第一PCE是否支持TLS和TCP AO。
发送单元1002，用于向所述通信设备所在域发送所述IGP路由通告消息，通常也可以说泛洪(英文：flood)所述IGP路由通告消息，以向所述通信设备所在域内成员通告所述第一PCE的传输能力。
进一步地，所述路由通告消息中还可以包括所述第一PCE的端口信息，所述端口信息包括端口类型和端口号。所述端口类型包括：基于TCP的PCEP(英文：PCEP over TCP)端口，基于TLS的PCEP(英文：PCEP over TLS)端口。或者，所述端口类型包括：基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，基于TLS的PCEP(英文：PCEP over TLS)端口；进一步可选地，如果所述第一PCE的传输能力信息还包括第四标志位，相应地所述端口类型包括：基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
具体地，IGP包括OSPF，IS-IS；相应地，所述通信设备为OSPF路由器，所述通信设备所在域为OSPF域，所述路由通告消息为OSPF LSA；或者，所述通信设备为IS-IS路由器，所述通信设备所在域为IS-IS域，所述路由通告消息为IS-IS LSA。
具体实现中，所述第一PCE的位置信息，例如IPv4地址或IPv6地址，可以携带在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中的PCE-ADDRESSsub-TLV中；并扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，在PCE能力标志(PCE-CAP-FLAGS)sub-TLV中定义三个目前未使用的标志位，作为上述的第一标志位、第二标志位和第三标志位，分别用于指示 所述第一PCE是否支持TCP MD5选项，所述第一PCE是否支持TCP AO，所述第一PCE是否支持TLS；进一步地，还可以定义第四标志位，用于指示所述所述第一PCE是否支持TLS和TCP AO。
OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV的格式可以如图2a所示。具体地，图2a中在PCE-ADDRESS sub-TLV中扩展的四个标志位和PCE能力描述的对应关系可以如下：
标志位(bits) 能力描述(capability description)
12 指示是否支持TCP MD5(PCEP over TCP MD5)
13 指示是否支持TCP AO(PCEP over TCP AO)
14 指示是否支持TLS(PCEP over TLS)
15 指示是否支持TLS和TCP AO(PCEP over TLS and TCP AO)
需要说明的是，图2a中以定义四个标志位12,13,14和15作为示例，上述各标志位及对应的能力描述也仅作为示例，并不构成对本发明的限定。
进一步地，还可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述第一PCE的端口信息的sub-TLV，格式可以如图2b所示。可以有两种实现方式携带所述第一PCE的端口信息：
一种是定义两个sub-TLV携带PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述第一PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述第一 PCE的传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
进一步地，所述通信设备还可以包括接收单元，用于在生成所述路由通告消息之前，接收所述第一PCE的注册信息，所述注册信息中包括所述第一PCE的传输能力。所述注册信息还可以包括PCE路径计算的范围、相邻PCE、通信能力和路径计算能力等。
进一步地，所述路由通告消息中还可以包括第二PCE的位置信息和传输能力信息；可选地，还包括所述第二PCE的端口信息。则相应地，所述接收单元，还用于在生成所述路由通告消息之前，接收所述第二PCE的注册信息，所述注册信息中包括所述第二PCE的传输能力。
本发明实施例提供的通信设备，通过扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义标志位指示PCE的传输能力，从而可以实现PCE传输能力的通告，使得PCC可以选取与自身传输能力匹配的PCE，保证PCC与PCE间有效地建立PCEP会话，从而提高PCC与PCE间路径计算的效率和成功率。
如图11所示，为本发明实施例提供的一种通信设备的结构示意图，本实施例中所述通信设备具体为PCC网元，用于实现本发明图4所示的方法，所述通信设备1100包括：处理器1101、存储器1102、通信接口1103和总线1104；其中，
处理器1101、存储器1102、通信接口1103通过总线1104相互连接；总线1104可以是外设部件互连标准(peripheral component interconnect，简称PCI)总线或扩展工业标准结构(extended industry standard architecture，简称EISA)总线等。所述总线可以分为地址总线、数据总线、控制总线等。为便于表示，图11中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
存储器1102，用于存放程序。具体地，程序可以包括程序代码，所述程序代码包括计算机操作指令。存储器1102可能包含高速随机存取存储器(random  access memory，简称RAM)，也可能还包括非易失性存储器(英文：non-volatile memory)，例如至少一个磁盘存储器。
所述通信接口1103，用于与其他通信设备进行通信。
处理器1101执行存储器1102所存放的程序，执行本发明实施例提供的确定路径计算单元的方法，包括：
接收至少一个路由通告消息，所述路由通告消息中包括PCE的位置信息和传输能力信息；所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP摘要算法5选项；所述第二标志位用于指示所述第一PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；可选地，所述PCE的传输能力信息还包括第四标志位，所述第四标志位用于指示所述PCE是否支持TLS和TCP AO；
根据预设选取策略和所述至少一个路由通告消息中PCE的传输能力信息，确定用于路径计算的PCE。
进一步地，所述路由通告消息中还可以包括所述PCE的端口信息，所述端口信息包括端口类型和端口号。所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口。或者，所述端口类型包括：基于TCP摘要算法5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口；可选地，还包括基于TLS和TCP AO的PCEP端口。
所述路由通告消息可以为IGP路由通告消息(具体可参考本发明图1所示的方法中所述)或BGP路由通告消息(具体可参考本发明图3所示的方法中所述)。其中，所述IGP路由通告消息可以为OSPF LSA或IS-IS LSA；具体实现中，所述PCE的位置信息，例如IPv4地址或IPv6地址，可以携带在OSPF LSA的PCED TLV或IS-IS LSA的PCED sub-TLV中的PCE-ADDRESS sub-TLV中；所述PCE的传输能力信息可以通过扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，在PCE-CAP-FLAGS sub-TLV中定义三个目前未使用的标志位分别作为上述的第 一标志位、第二标志位和第三标志位；进一步地，还可以定义第四标志位。OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV的具体格式可以如图2a所示。具体地，图2a中PCE-ADDRESS sub-TLV中扩展的四个标志位和PCE能力描述的对应关系可以如下：
标志位(bits) 能力描述(capability description)
12 指示是否支持TCP MD5(PCEP over TCP MD5)
13 指示是否支持TCP AO(PCEP over TCP AO)
14 指示是否支持TLS(PCEP over TLS)
15 指示是否支持TLS和TCP AO(PCEP over TLS and TCP AO)
需要说明的是，图2a中以定义四个标志位12,13,14和15作为示例，上述各标志位对应的能力描述也仅作为示例，并不构成对本发明的限定。
进一步地，所述IGP路由通告消息中还可以包括所述PCE的端口信息，可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。还可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。可以有两种实现方式携带所述第一PCE的端口信息：
一种是定义两个sub-TLV携带PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述PCE的传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和 TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
所述BGP路由通告消息中包括所述PCE的位置信息和传输能力信息，可以通过扩展BGP协议来实现。例如，在BGP协议的NLRI TLV中定义PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV携带在BGP路由通告消息中，其中PCE-ADDRESS sub-TLV用于携带所述PCE的位置信息，PCE-CAP-FLAGS sub-TLV用于携带所述PCE的传输能力信息，具体格式可以同扩展的OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，如图2a所示。进一步地，所述BGP路由通告消息中还可以包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；与所述IGP路由通告消息相应地，所述端口类型包括：PCEP over TCP端口，PCEP over TLS端口；或者，所述端口类型包括：PCEP over TCP MD5端口，基PCEP over TCP AO端口，PCEP over TLS端口；进一步地，还可以包括PCEP over TLS and TCP AO端口。具体实现中，可以扩展BGP协议，例如，在NLRI中携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。与对OSPF协议或IS-IS协议的扩展相应地，同样可以有上述两种实现方式携带所述PCE的端口信息。
可以理解的是，本发明实施例中，所述路由通告消息中可以仅包括一个PCE的位置信息和传输能力信息；也可以包括多个PCE的位置信息和传输能力信息。所述PCC可以根据一个路由通告消息中的一个或多个PCE的传输能力信息，也可以根据多个路由通告消息中所有PCE的传输能力信息来确定用于路径计算的PCE。
所述预设选取策略包括：
选取具备所述PCC支持的传输能力的PCE用于路径计算。
若所述PCC既支持TCP AO也支持TCP MD5，则优先选取支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，选取支持TCP MD5的PCE用于路径计算；
若所述PCC支持TLS和TCP AO，则根据安全性需求确定用于路径计算的PCE；所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全； 具体地，若所述PCC支持TLS和TCP AO，当安全性需求为传输层及敏感数据安全时，选取支持TLS和TCP AO的PCE用于路径计算；当安全性需求为传输层时，选取支持TCP AO的PCE用于路径计算；当安全性需求为敏感数据安全时，选取支持TLS的PCE用于路径计算。
进一步地，还可以结合PCE的优先级或PCE的负载信息或所述PCC的喜好，确定一个PCE用于路径计算，则所述预设选取策略包括：
结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个具备所述PCC支持的传输能力的PCE用于路径计算。具体的，以结合PCE的优先级为例，所述预设选取策略包括：若仅有一个PCE具备所述PCC支持的传输能力，则选取该PCE用于路径计算；若多个PCE具备所述PCC支持的传输能力，选取所述多个PCE中优先级较高的PCE用于路径计算；
若所述PCC既支持TCP AO也支持TCP MD5，则结合PCE的优先级或PCE的负载信息或所述PCC的喜好，优先选取支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取支持TCP MD5的PCE用于路径计算。具体的，以结合PCE的优先级为例，若所述PCC既支持TCP AO也支持TCP MD5，如果多个PCE支持TCP AO，选择优先级较高的PCE用于路径计算；如果仅有一个PCE支持TCP AO，则确定该PCE用于路径计算；如果任何一个PCE都不支持TCP AO，则若多个PCE支持TCP MD5，选择优先级较高的PCE用于路径计算，若仅有一个PCE支持TCP MD5，确定该PCE用于路径计算；
若所述PCC支持TLS和TCP AO，则根据安全性需求，结合PCE的优先级或PCE的负载信息或所述PCC的喜好，确定一个用于路径计算的PCE。具体地，若所述PCC支持TLS和TCP AO，当多个PCE满足所述安全性需求时，可以根据所述多个PCE的优先级或PCE的负载信息或所述PCC的喜好，选取优先级较高的PCE用于路径计算；当仅有一个PCE满足所述安全性需求时，确定该PCE用于路径计算。
可选地，存储器1102，还用于保存所述预设选取策略。
具体实现中，PCE的优先级信息可以参考目前标准规范，携带在OSPF协议的PCED TLV或者IS-IS协议的PCED sub-TLV。
可选地，所述PCE负载信息包括PCE的负荷能力、当前负载情况等。当结合PCE的负载信息选取用于路径计算的PCE时，例如可以选择负荷能力强，当前负载较小的PCE用于路径计算。当然，所述预设选取策略也可以结合PCC的本地策略，例如本地策略为选取支持传输能力最多的PCE；当然PCC的本地策略可以静态配置，也可以根据需求动态调整。
需要说明的是，对于PCC按照本发明技术方案选取PCE之后，与PCE建立PCEP会话、提交路径计算请求和获取路径计算结果等，可参考目前标准规范，本发明实施例在此不再赘述。
本发明实施例提供的PCC，接收携带PCE传输能力信息的路由通告消息，并根据PCE的传输能力和预设选取策略，选择与自身传输能力匹配的PCE用于路径计算，可以提高PCC与PCE间建立PCEP会话的成功率，从而提高路径计算的效率。
如图12所示，为本发明实施例提供的另一种通信设备的结构示意图，本实施例中所述通信设备具体为BGP路由器，用于实现本发明图3所示的方法，所述通信设备1200包括：处理器1201、存储器1202、通信接口1203和总线1204；其中，
处理器1201、存储器1202、通信接口1203通过总线1204相互连接；总线1204可以是PCI总线或EISA总线等。所述总线可以分为地址总线、数据总线、控制总线等。为便于表示，图12中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
所述通信接口1203，用于与其他通信设备进行通信。
存储器1202，用于存放程序。具体地，程序可以包括程序代码，所述程序 代码包括计算机操作指令。存储器1202可能包含高速RAM，也可能还包括非易失性存储器(英文：non-volatile memory)，例如至少一个磁盘存储器。
处理器1201执行存储器1202所存放的程序，执行本发明实施例提供的通告传输能力的方法，包括：
接收来自AS域的至少一个IGP路由通告消息，所述IGP路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP摘要算法5选项；所述第二标志位用于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；可选地，所述PCE的传输能力信息还包括第四标志位，用于指示所述PCE是否支持TLS和TCP AO；
根据所述至少一个IGP路由通告消息生成BGP路由通告消息，所述BGP路由通告消息中包括所述至少一个IGP路由通告消息中的PCE的位置信息和传输能力信息；
将所述BGP路由通告消息发送到所述AS以外的AS域。
假设所述至少一个IGP路由通告消息来自第一AS域，所述BGP路由器位于所述第一AS和第二AS边界上，则将所述BGP路由通告消息发送到所述第二AS，以向所述第二AS内成员通告所述第一PCE的传输能力。
所述通信设备1200具体可以为BGP speaker。
所述IGP路由通告消息为OSPF LSA或者IS-IS LSA。
所述BGP路由器具体可以为BGP speaker。
所述PCE的传输能力信息可以通过扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV的PCE-CAP-FLAGS sub-TLV实现，在PCE-CAP-FLAGS sub-TLV中定义三个目前未使用的标志位，作为上述的第一标志位、第二标志位和第三标志位，分别用于指示所述第一PCE是否支持TCP MD5选项，所述第一PCE是否支持TCP AO，所述第一PCE是否支持TLS；进一步地，还可以定义第四标志 位，用于指示所述所述第一PCE是否支持TLS和TCP AO。
OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV的格式可以如图2a所示。具体可参考本发明实施例提供的方法中所述，在此不再赘述。
具体实现中，可以扩展BGP协议，例如，在NLRI TLV中，定义PCE-ADDRESS sub-TLV和PCE-CAP-FLAGS sub-TLV携带在BGP路由通告消息中。可选地，PCE的传输能力信息也可以通过扩展BGP协议的能力选项参数(英文：capability optional parameter)，定义目前未使用的能力编码，用于标识PCE的传输能力。具体地对BGP协议的扩展，可参考如本发明图3所示方法中所述，在此不再赘述。
进一步地，所述IGP路由通告消息中还可以包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；所述端口类型包括：基于TCP的PCEP(英文：PCEP over TCP)端口，基于TLS的PCEP(英文：PCEP over TLS)端口。或者，所述端口类型包括：基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，基于TLS的PCEP(英文：PCEP over TLS)端口；进一步地，还可以包括基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。具体实现中，可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述第一PCE的端口信息的sub-TLV，格式可以如图2b所示，具体可参考本发明图1所示方法中所述，在此不再赘述。
则相应地，所述BGP路由通告消息中还可以包括所述PCE的端口信息。具体实现中，可以扩展BGP协议，例如，在NLRI中定义携带所述PCE的端口信息的sub-TLV，格式可以如图2b所示。类似于对OSPF协议或IS-IS协议的扩展，同样可以有两种实现方式携带所述PCE的端口信息：
一种是定义两个sub-TLV携带PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO 的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述第一PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述第一PCE的传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
可选地，在接收所述至少一个IGP路由通告消息之后，生成所述BGP路由通告消息之前，所述方法还包括：检查所述至少一个IGP路由通告消息中是否包含PCE的传输能力信息；如果确定所述至少一个IGP路由通告消息中包含PCE的传输能力信息，则生成所述BGP路由通告消息；如果确定所述至少一个IGP路由通告消息中没有包含PCE的传输能力信息，则按照现有标准规范进行处理。
本发明实施例中，所述通信设备可以仅根据一个IGP路由通告消息生成一个BGP路由通告消息，也可以根据一个AS域收到的多个IGP路由通告消息生成一个BGP路由通告消息，将多个IGP路由通告消息中携带的各个PCE的位置信息和传输能力信息通过一个BGP路由通告消息发送到其他AS域。举例来说，假设所述通信设备收到两个IGP路由通告消息：第一IGP路由通告消息和第二IGP路由通告消息，第一IGP路由通告消息中包括第一PCE的位置信息和传输能力信息，第二路由通告消息中包括第二PCE的位置信息和传输能力信息，第一IGP路由通告消息与第二IGP路由通告消息来自一个AS域；则所述通信设备根据所述第一路由通告消息和所述第二路由通告消息生成所述BGP路由通告消息，所述BGP路由通告消息中包括第一PCE的位置信息和传输能力信息，以及第二PCE的位置信息和传输能力信息。
可以理解的是，所述IGP路由通告消息中可以仅包括一个PCE的位置信息和传输能力信息，也可以包括多个PCE的位置信息和传输能力信息。则相应地， 所述BGP路由通告消息中包括所述IGP路由通告消息中的多个PCE的位置信息和传输能力信息。
本发明实施例提供的通信设备，通过扩展的BGP协议，实现AS间PCE传输能力的通告，可以保证PCC跨AS与PCE有效建立PCEP会话，从而提高PCC与PCE间路径计算的效率和成功率。
如图13所示，为本发明实施例提供的又一种通信设备的结构示意图，本实施例中所述通信设备具体为IGP路由器，用于实现本发明图1所示的方法，所述通信设备1300包括：处理器1301、存储器1302、通信接口1303和总线1304；其中，
处理器1301、存储器1302、通信接口1303通过总线1304相互连接；总线1304可以是PCI总线或EISA总线等。所述总线可以分为地址总线、数据总线、控制总线等。为便于表示，图13中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
所述通信接口1303，用于与其他通信设备进行通信。
存储器1302，用于存放程序。具体地，程序可以包括程序代码，所述程序代码包括计算机操作指令。存储器1302可能包含高速RAM，也可能还包括非易失性存储器(英文：non-volatile memory)，例如至少一个磁盘存储器。
处理器1301执行存储器1302所存放的程序，执行本发明实施例提供的通告传输能力的方法，包括：
生成IGP路由通告消息，所述路由通告消息中包括第一PCE的位置信息和传输能力信息；所述第一PCE的传输能力信息包括第一标志位、第二标志位和第三标志位；其中，所述第一标志位用于指示所述第一PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项(英文：PCEP over TCP MD5)；所述第二标志位用于指示所述第一PCE是否支持TCP认证配置选项AO(英文：PCEP over TCP AO)；所述第三标志位用于指示所述第一PCE是否支持传输层安全TLS(英 文：PCEP over TLS)；可选地，所述第一PCE的传输能力信息还包括第四标志位，所述第四标志位用于指示所述第一PCE是否支持TLS和TCP AO(英文：PCEP over TLS and TCP AO)；
向所述通信设备1300所在域发送所述IGP路由通告消息，以向所述通信设备所在域内成员通告所述第一PCE的传输能力。
通常也可以说泛洪(英文：flood)所述IGP路由通告消息。
进一步地，所述路由通告消息中还可以包括所述第一PCE的端口信息，所述端口信息包括端口类型和端口号。所述端口类型包括：基于TCP的PCEP(英文：PCEP over TCP)端口，基于TLS的PCEP(英文：PCEP over TLS)端口。或者，所述端口类型包括：基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，基于TLS的PCEP(英文：PCEP over TLS)端口；进一步可选地，如果所述第一PCE的传输能力信息还包括第四标志位，相应地所述端口类型包括：基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
具体地，IGP包括OSPF，IS-IS；相应地，所述通信设备为OSPF路由器，所述通信设备所在域为OSPF域，所述路由通告消息为OSPF LSA；或者，所述通信设备为IS-IS路由器，所述通信设备所在域为IS-IS域，所述路由通告消息为IS-IS LSA。
具体实现中，所述第一PCE的位置信息，例如IPv4地址或IPv6地址，可以携带在OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV中的PCE-ADDRESSsub-TLV中；并扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，在PCE能力标志(PCE-CAP-FLAGS)sub-TLV中定义三个目前未使用的标志位，作为上述的第一标志位、第二标志位和第三标志位，分别用于指示所述第一PCE是否支持TCP MD5选项，所述第一PCE是否支持TCP AO，所述第一PCE是否支持TLS；进一步地，还可以定义第四标志位，用于指示所述所述第一PCE是否支持TLS和TCP AO。OSPF协议的PCED TLV或IS-IS协议的PCED  sub-TLV的格式可以如图2a所示。具体地，图2a中在PCE-ADDRESS sub-TLV中扩展的四个标志位和PCE能力描述的对应关系可以如下：
标志位(bits) 能力描述(capability description)
12 指示是否支持TCP MD5(PCEP over TCP MD5)
13 指示是否支持TCP AO(PCEP over TCP AO)
14 指示是否支持TLS(PCEP over TLS)
15 指示是否支持TLS和TCP AO(PCEP over TLS and TCP AO)
需要说明的是，图2a中以定义四个标志位12,13,14和15作为示例，上述各标志位及对应的能力描述也仅作为示例，并不构成对本发明的限定。
进一步地，还可以扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义携带所述第一PCE的端口信息的sub-TLV，格式可以如图2b所示。可以有两种实现方式携带所述第一PCE的端口信息：
一种是定义两个sub-TLV携带PCE的端口信息，其中一个sub-TLV携带基于TCP的PCEP(英文：PCEP over TCP)端口，一个sub-TLV携带基于TLS的PCEP(英文：PCEP over TLS)端口。其中，支持TCP MD5选项与支持TCP AO的共用携带PCEP over TCP端口的sub-TLV，支持TLS的使用PCEP over TLS端口的sub-TLV；可选地，如果所述第一PCE的传输能力信息还包括第四标志位，则支持TLS与支持TLS和TCP AO的共用PCEP over TLS端口的sub-TLV。
另一种是定义三个sub-TLV分别携带基于TCP MD5选项的PCEP(英文：PCEP over TCP MD5)端口，基于TCP AO的PCEP(英文：PCEP over TCP AO)端口，和基于TLS的PCEP(英文：PCEP over TLS)端口。进一步地，如果所述第一PCE的传输能力信息还包括第四标志位，可以再定义一个sub-TLV用于携带基于TLS和TCP AO的PCEP(英文：PCEP over TLS and TCP AO)端口。
进一步地，在生成所述路由通告消息之前，所述方法还包括：接收所述第一PCE的注册信息，所述注册信息中包括所述第一PCE的传输能力。
所述注册信息还可以包括所述第一PCE路径计算的范围、相邻PCE、通信能 力和路径计算能力等。可选地，所述存储器1302还用于保存所述第一PCE的注册信息。
进一步地，所述路由通告消息中还可以包括第二PCE的位置信息和传输能力信息；可选地，还包括所述第二PCE的端口信息。则相应地，所述接收单元，还用于在生成所述路由通告消息之前，接收所述第二PCE的注册信息，所述注册信息中包括所述第二PCE的传输能力。
本发明实施例提供的通信设备，通过扩展OSPF协议的PCED TLV或IS-IS协议的PCED sub-TLV，定义指示PCE的传输能力，从而可以实现PCE传输能力的通告，使得PCC可以选取与自身传输能力匹配的PCE，保证PCC与PCE间有效地建立PCEP会话，从而提高PCC与PCE间路径计算的效率和成功率。
本领域技术人员应该还可以进一步意识到，结合本文中所公开的实施例描述的各示例的单元及步骤，、能够通过计算机软件来实现，，在上述说明中已经按照功能一般性地描述了各示例的组成及步骤。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。本领域技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本发明的范围。
结合本文中所公开的实施例描述的方法或算法的步骤可以通过、处理器执行的软件模块来实施。软件模块可以置于随机存储器(英文：RAM)、只读存储器(英文：ROM)、电可编程ROM、电可擦除可编程ROM、寄存器、硬盘、可移动磁盘、、或技术领域内所公知的任意其它形式的存储介质中。
以上所述的具体实施方式，对本发明的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本发明的具体实施方式而已，并不用于限定本发明的保护范围，凡在本发明的技术方案的基础上，所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (13)

  1. 一种确定路径计算单元的方法，其特征在于，所述方法包括：
    路径计算客户PCC接收至少一个路由通告消息，所述路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；
    所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项；所述第二标志位用于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；
    根据预设选取策略和所述至少一个路由通告消息中PCE的传输能力信息，确定用于路径计算的PCE。
  2. 根据权利要求1所述的方法，其特征在于，所述路由通告消息中还包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；
    所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口；或者，
    所述端口类型包括：基于TCP MD5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口。
  3. 根据权利要求1或2所述的方法，其特征在于，所述预定选取策略包括：
    选取具备所述PCC支持的传输能力的PCE用于路径计算；
    若所述PCC支持TCP MD5，则选取支持TCP MD5的PCE用于路径计算；或者
    若所述PCC支持TCP AO，则选取支持TCP AO的PCE用于路径计算；或者
    所述PCC支持TLS，则选取支持TLS的PCE用于路径计算。
  4. 根据权利要求1或2或3所述的方法，其特征在于，所述预定选取策略包括：
    选取具备所述PCC支持的传输能力的PCE用于路径计算；
    若所述PCC既支持TCP AO也支持TCP MD5，则优先选取支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，选取支持TCP MD5的PCE用于路径计算；或者
    若所述PCC支持TLS和TCP AO，则根据安全性需求，选取用于路径计算的PCE，所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全；或者
    结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个具备所述PCC支持的传输能力的PCE用于路径计算；
    若所述PCC既支持TCP AO也支持TCP MD5，则结合PCE的优先级或PCE的负载信息或所述PCC的喜好，优先选取一个支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，结合PCE的优先级，选取一个支持TCP MD5的PCE用于路径计算；或者
    若所述PCC支持TLS和TCP AO，则根据安全性需求，结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个用于路径计算的PCE，所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全。
  5. 根据权利要求1至4任一项所述的方法，其特征在于，所述路由通告消息包括内部网关协议IGP路由通告消息，边界网关协议BGP路由通告消息。
  6. 一种通信设备，其特征在于，包括：
    接收单元，用于接收至少一个路由通告消息，所述路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项；所述第二标志位用于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；
    确定单元，用于根据预设选取策略和所述至少一个路由通告消息中PCE的传输能力信息，确定用于路径计算的PCE。
  7. 根据权利要求6所述的通信设备，其特征在于，所述路由通告消息中还包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；
    所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口；或者，
    所述端口类型包括：基于TCP MD5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口。
  8. 根据权利要求6或7所述的通信设备，其特征在于，所述预定选取策略包括：
    选取具备所述PCC支持的传输能力的PCE用于路径计算；
    若所述PCC支持TCP MD5，则选取支持TCP MD5的PCE用于路径计算；或者
    若所述PCC支持TCP AO，则选取支持TCP AO的PCE用于路径计算；或者
    所述PCC支持TLS，则选取支持TLS的PCE用于路径计算。
  9. 根据权利要求6或7或8所述的通信设备，其特征在于，所述预定选取策略包括：
    选取具备所述PCC支持的传输能力的PCE用于路径计算；
    若所述PCC既支持TCP AO也支持TCP MD5，则优先选取支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，选取支持TCP MD5的PCE用于路径计算；或者
    若所述PCC支持TLS和TCP AO，则根据安全性需求，选取用于路径计算的PCE，所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全；或者
    结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个具备所述PCC支持的传输能力的PCE用于路径计算；
    若所述PCC既支持TCP AO也支持TCP MD5，则结合PCE的优先级或PCE的负载信息或所述PCC的喜好，优先选取一个支持TCP AO的PCE用于路径计算，在任何一个PCE都不支持TCP AO的情况下，结合PCE的优先级，选取一个支持 TCP MD5的PCE用于路径计算；或者
    若所述PCC支持TLS和TCP AO，则根据安全性需求，结合PCE的优先级或PCE的负载信息或所述PCC的喜好，选取一个用于路径计算的PCE，所述安全性需求包括：传输层安全，敏感数据安全，传输层及敏感数据安全。
  10. 一种通信设备，其特征在于，包括：
    接收单元，用于接收来自自治系统AS域的至少一个内部网关协议IGP路由通告消息，所述IGP路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用于指示所述PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项；所述第二标志位用于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；
    生成单元，用于根据所述至少一个IGP路由通告消息生成边界网关协议BGP路由通告消息，所述BGP路由通告消息中包括所述至少一个IGP路由通告消息中的PCE的位置信息和传输能力信息；
    发送单元，用于将所述BGP路由通告消息发送到所述AS域以外的AS域。
  11. 根据权利要求10所述的通信设备，其特征在于，所述IGP路由通告消息中还包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口；或者，所述端口类型包括：基于TCP消息摘要算法第五版MD5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口；
    相应地，所述BGP路由通告消息中还包括所述至少一个IGP路由通告消息中的PCE的端口信息。
  12. 一种通信设备，其特征在于，包括：
    生成单元，用于生成内部网关协议IGP路由通告消息，所述IGP路由通告消息中包括路径计算单元PCE的位置信息和传输能力信息；所述PCE的传输能力信息包括第一标志位，第二标志位和第三标志位；其中，所述第一标志位用 于指示所述PCE是否支持传输控制协议TCP消息摘要算法第五版MD5选项；所述第二标志位用于指示所述PCE是否支持TCP认证配置选项AO；所述第三标志位用于指示所述PCE是否支持传输层安全TLS；
    发送单元，用于向所述通信设备所在域发送所述IGP路由通告消息。
  13. 根据权利要求12所述的方法，其特征在于，所述IGP路由通告消息中还包括所述PCE的端口信息，所述端口信息包括端口类型和端口号；
    所述端口类型包括：基于TCP的路径计算协议PCEP端口，基于TLS的PCEP端口；或者，
    所述端口类型包括：基于TCP消息摘要算法第五版MD5选项的PCEP端口，基于TCP AO的PCEP端口，基于TLS的PCEP端口。
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