CN101505227B - Method, device and system for implementing point to multi-point pseudowire - Google Patents

Abstract

The invention discloses a method for achieving point-to-multipoint pseudo-wires, which comprises the following steps: establishing a border gateway protocol (BGP) protocol with downstream node equipment through negotiation according to the collected network topology information; and sending a BGP message to the downstream node equipment, wherein the BGP message carries point-to-multipoint pseudo-wire labels specifically distributed to a virtual private multicast service (VPMS) embodiment to establish the point-to-multipoint pseudo-wires. The embodiment of the invention also provides corresponding equipment and a system. The technical proposal of the invention does not need static configuration, but needs dynamic establishment, thus the efficiency for establishing the point-to-multipoint pseudo-wires is improved; besides, relative to the static configuration, the accuracy rate of configuration is improved.

Description

A method, device and system for realizing point-to-multipoint pseudowire

technical field

The present invention relates to the technical field of electrical communication, in particular to a method, device and system for realizing Point to Multi-point Pseudo Wire (P2MPPW, Point to Multi-point Pseudo Wire).

Background technique

In Layer 2 Virtual Private Network (L2VPN, Layer 2 Virtual Private Network), a variety of service types are defined, for example, virtual private line service (VPWS, Virtual Private Wire Service) and virtual private LAN service (VPLS, Virtual Private LAN Service) wait. The VPWS service provides a point-to-point L2VPN service, while the VPLS is used to emulate an Ethernet LAN (LocalArea Network) service. In the existing L2VPN, simple point-to-multipoint services or LAN services can be provided, but the provision of point-to-multipoint (P2MP, Point to Multi-Point) services is relatively cumbersome. To implement P2MP services based on the existing architecture, it is necessary to complete the establishment process of the path to each receiving end through the source, and the source needs to send data to each receiving end, which will cause an excessive burden on the source operator's edge (PE, Provider Edge) device It is heavy and causes a serious waste of network resources, and the Virtual Private Multicast Service (VPMS, Virtual Private Multicast Service) can meet the requirements of this P2MP service.

VPMS is a new service architecture that can provide a point-to-multipoint transmission path to meet the transmission requirements of P2MP services. The VPMS is specifically implemented through a P2MP PW established on a packet switching network (PSN, PacketSwitching Network) tunnel. The key point of VPMS is the establishment of P2MP PW.

The existing P2MP PW establishment mechanism can be completed through static configuration. In practical applications, by completing statistics on the entire network resources and nodes, and configuring specific VPMS service instances on specific P2MP PSN tunnels on the carrier edge PE equipment The label (VPMS Instance Label), the VPMS service instance identifier (VPMS Instance ID) and the established P2MP PW topology identification information (P2MP PW Topology Identify ID), thereby establishing a P2MP PW.

During the research and practice of the prior art, the inventors of the present invention found that due to the static configuration in the prior art, it is necessary to make statistics on the entire network resources and nodes during the configuration, so the resources to be maintained are cumbersome and the workload is heavy. Large, and may cause misconfiguration.

Contents of the invention

Embodiments of the present invention provide a method, device and system for realizing a point-to-multipoint pseudowire, which can improve the efficiency and accuracy of establishing a point-to-multipoint pseudowire.

The embodiment of the present invention is specifically realized through the following technical solutions:

A method of implementing a point-to-multipoint pseudowire, comprising:

According to the collected network topology information, negotiate with downstream node devices to establish a Border Gateway Protocol BGP connection;

Sending a BGP message to a downstream node device, the BGP message carrying a point-to-multipoint pseudowire label allocated for a specific virtual private multicast service VPMS instance, and establishing a point-to-multipoint pseudowire.

A router, comprising: an information collection unit, a connection establishment unit, and a first sending unit, wherein:

an information collection unit, configured to collect network topology information;

A connection establishment unit, configured to negotiate with downstream node devices to establish a Border Gateway Protocol (BGP) connection according to the collected network topology information;

The first sending unit is configured to send a BGP message to a downstream node device after the BGP connection is established, wherein the BGP message carries a point-to-multipoint pseudowire label allocated for a specific virtual private multicast service VPMS instance, and establishes Point-to-multipoint pseudowires.

A system for implementing a point-to-multipoint pseudowire, comprising: a first node device and a second node device, the second node device being a downstream node device, wherein:

The first node device is configured to collect network topology information, and negotiate with the second node device to establish a Border Gateway Protocol BGP connection according to the collected network topology information; and after the BGP connection is established, send the message to the second node The device sends a BGP message, and the BGP message carries a point-to-multipoint pseudowire label allocated for a specific virtual private multicast service VPMS instance, and establishes a point-to-multipoint pseudowire;

The second node device is configured to collect network topology information, negotiate with the first node device to establish a BGP connection according to the collected network topology information; receive the BGP message sent by the first node device, and obtain the BGP message from the message Obtain the point-to-multipoint pseudo-wire label assigned to the specific VPMS instance, and establish a point-to-multipoint pseudo-wire with the first node device.

In the embodiment of the present invention, after the BGP connection is established with the downstream node device, a BGPUPDATE message is generated and sent to the downstream node device. The BGP UPDATE message carries the P2MP PW label allocated for the specific VPMS service instance, thereby The P2MP PW can be established, and since the method does not require static configuration, but is dynamically established, the efficiency of establishing the P2MP PW can be improved; and compared with the static configuration, the accuracy of configuration can be improved.

Description of drawings

Fig. 1 is the schematic diagram of P2MP SS-PW reference model in the embodiment of the present invention;

Fig. 2 is the schematic diagram of P2MP MS-PW reference model in the embodiment of the present invention;

Fig. 3 is a flow chart of the first embodiment of the method for realizing P2MP SS-PW in the embodiment of the present invention;

Fig. 4 is a schematic diagram of a message header structure of a BGP message in an embodiment of the present invention;

Fig. 5 is a schematic diagram of the BGP OPEN message body structure in the embodiment of the present invention;

Fig. 6 is a schematic structural diagram of the expanded Optional Parameters in the embodiment of the present invention;

Fig. 7 is the schematic diagram of the BGP UPDATE message body structure after expansion in the embodiment of the present invention;

Fig. 8 is the BGP VPMS NLRI regional structure schematic diagram that expands in the embodiment of the present invention;

FIG. 9 is a schematic structural diagram of Embodiment 2 of a method for realizing P2MP PW in an embodiment of the present invention;

Fig. 10 is the BGP UPDATE message body that contains P2MP PW revocation information in the embodiment of the present invention;

Fig. 11 is a flow chart of Embodiment 3 of the method for realizing P2MP PW in the embodiment of the present invention;

FIG. 12 is a schematic structural diagram of router 1 in an embodiment of the present invention;

FIG. 13 is a schematic structural diagram of router 2 in an embodiment of the present invention;

Fig. 14 is a schematic diagram of the structure of router 3 in the embodiment of the present invention;

FIG. 15 is a schematic structural diagram of router 4 in an embodiment of the present invention;

FIG. 16 is a schematic structural diagram of Embodiment 1 of a system implementing P2MP PW in an embodiment of the present invention;

Fig. 17 is a schematic structural diagram of the second embodiment of the system for realizing P2MP PW in the embodiment of the present invention.

Detailed ways

Embodiments of the present invention provide a method, device, and system for implementing a point-to-multipoint pseudowire. By extending the Border Gateway Protocol (BGP, Border Gateway Protocol) to implement P2MP PW, the efficiency and accuracy of P2MPPW establishment can be improved. Detailed description will be given below with reference to the drawings.

BGP is one of the most important routing protocols on the Internet, and can be applied to scenarios across autonomous domains (AS, Autonomour System) and across operators. BGP is a dynamic routing discovery protocol between autonomous systems. Its basic function is to automatically exchange loop-free routing information between autonomous systems. By exchanging path reachability information with autonomous system number (AS) sequence attributes, To construct the topology map of the autonomous area, thereby eliminating routing loops and implementing user-configured routing policies.

Among them, the autonomous system refers to: a collection of routers managed by the same technical management organization and using a unified routing strategy. Each autonomous system has a unique autonomous system number, which is assigned by the Internet Authorized Management Organization. Different autonomous systems are distinguished by different numbers. Currently, autonomous system numbers range from 1 to 65535, where 1 to 65411 are registered Internet numbers and 65412 to 65535 are private network numbers.

BGP provides four message types, which are OPEN, KEEPALIVE, UPDATE and NOTIFICATION. Among them, BGP peers send OPEN messages to exchange their own version, autonomous system number, hold time, BGP identifier and other information for negotiation. What the UPDATE message carries is routing update information, including revoked routing information, reachability routing information and its path attributes. When BGP detects an error (connection interruption, negotiation error, message error, etc.), it sends a NOTIFICATION message to close the peer connection. KEEPALIVE messages are periodically sent between BGP peers to ensure the validity of the connection.

In the embodiment of the present invention, according to the collected network topology information, a BGP connection is negotiated with the downstream node device; and then a BGP message is sent to the downstream node device, and the BGP message carries the point allocation for a specific VPMS instance. To the multipoint pseudowire tag, create a point-to-multipoint pseudowire.

P2MP PW has two models: P2MP single segment pseudo wire (SS-PW, Single Segment Pseudo Wire) and P2MP multi segment pseudo wire (MS-PW, Multiple Segment Pseudo Wire), refer to Figure 1 and Figure 2 respectively.

For P2MP SS-PW, P2MP PW is a PW tree. In an independent P2MP PW topology, it includes a source end and multiple leaf end points. The source end is connected to each leaf end point through a P2MP PW, and the leaf end points are connected to each other. Isolated, no communication between leaf endpoints.

FIG. 1 is a schematic diagram of a P2MP SS-PW reference model in an embodiment of the present invention. A user edge (CE, Customer Edge) device 101 is an access device on the user side, and is responsible for passing user traffic through an access circuit (AC, Access Circuit) 102. Send to the PE device 103; the PE device 103 must support the L2VPN protocol procedure, including establishing a pseudowire connection from the PE device 103 to the peer PE device 103 through signaling on the control plane, and completing the Layer 2 data link frame to the peer PE device 103 on the data plane. Encapsulation/decapsulation and corresponding processing functions of Internet Protocol/Multiple Protocol Label Switching (IP/MPLS, International Protocol/Multiple Protocol Label Switching) marked packets, and transmit the marked packets to the peer PE device through PW105 in P2MP PSN tunnel 104 103; the operator (P, Provider) equipment 106 supports the transparent transmission of L2VPN service flow, does not support the L2VPN procedure, and only plays the role of providing a bearer channel, and the P2MP PSN tunnel 104 established between the PE equipment 103 can pass through multiple P equipment 106 ; AC102 usually refers to the asynchronous transfer mode (ATM, Asynchronous Transfer Mode) virtual circuit, frame relay (FR, Frame Router) virtual circuit or Ethernet virtual local area network (VLAN, Virtul Local Area Network) chain used by users to access the L2VPN system PW105 refers to the connection established between PE devices 103 using L2VPN signaling. PE device 103 transmits the Layer 2 data frame from AC102 to the peer PE device 103 through PW105, and the peer PE device 103 restores or regenerates The Layer 2 link frame is transmitted to the opposite end AC102; multiple PW105 can be multiplexed in one P2MP PSN tunnel 104 and transmitted from the PE device 103 to the opposite end PE device 103.

In VPMS applications, for a unidirectional P2MP SS-PW, a point-to-multipoint link is provided between the source PE device 103-1 and the leaf PE devices 103-2, PE devices 103-3, and PE devices 103-4. simulation example. In this architecture, PE devices can be divided into two sets, namely source set and leaf set. Devices in the same set do not send other data packets except control packets.

The CE device 101 is connected to the PW105 through the AC102, and the AC102 is directional, that is, it has two characteristics of receiving and sending. Thus, a device can determine its own role by the state of the AC it is connected to. In some special cases, for example, a PE device 103 is connected to multiple ACs 102, which include both the sending characteristic AC102 and the receiving characteristic AC102, then this PE device 103 will belong to both the source set and the leaf set. In the embodiment of the present invention, the BGP peer entity is the source PE device and the leaf PE device connected through the P2MP PW.

Referring to Fig. 3, it is a flow chart of the first embodiment of the method for implementing P2MP SS-PW in the embodiment of the present invention. According to the collected network topology information, a BGP connection is established between the source PE device and the leaf PE device, and the BGP connection is established Finally, the source PE device sends a BGP message to the leaf PE device. The BGP message carries the P2MP PW label allocated for a specific VPMS instance, and establishes a P2MP PW. The following describes in detail the specific scenarios, and the specific steps are as follows:

S301: Configure information for establishing a P2MP SS-PW on the PE device;

For example, the following information for establishing a P2MP SS-PW can be configured on the source PE device and the leaf PE device: VPMS instance identifier and P2MP PW identifier (ID, Identify), used to identify a P2MP tree.

The type of configured information varies depending on the type of forwarding equivalence class (FEC, Forwarding EquivalenceClass) used. For example, when using FEC128, you need to configure the P2MPPW ID and the IP address of the remote PE. When using FEC 129 When configuring the same connection group identifier (AGI, Attachment Group Identifier), P2MP PW ID and device IP address. In the implementation of the present invention, the P2MP PW ID is mainly configured for the BGP application.

S302: The PE device collects network topology information;

In specific implementation, the network topology information and P2MP PSN tunnel information can be collected through the network management static configuration, and the source PE device and the leaf PE device can also use the BGP automatic discovery mechanism to complete the collection of network topology information and P2MP PSN tunnel information. For example, it is possible to know the identification device belonging to a specific VPMS instance and the AC state it is connected to (because the AC state can determine the role of the PE in the network, that is, determine whether the device belongs to the source device or the leaf device), etc.

S303, the PE device negotiates to establish a BGP connection by sending an OPEN message;

Among them, the BGP OPEN message can be extended to indicate that it supports VPMS performance by carrying BGP performance parameters in the BGP OPEN message.

A BGP message is usually composed of a message header and a message body. Among them, the message header structure of a BGP message is shown in Figure 4. Authentication information (Marker): 16 bytes, all 1, the role of this mark is mainly It is used to detect whether the synchronization between BGP peers is lost.

Length of the message (Length): 2 bytes, indicating the length of the entire message, including the length of the header. The minimum BGP message length is 19 bytes (KEEPALIVE message), and the maximum length is 4096 bytes.

Message type (Type): 1 byte, indicating the message type, such as OPEN, UPDATE message, etc., wherein: 1 means OPEN message, 2 means UPDATE message, 3 means NOTIFICATION message, 4 means KEEPALIVE message.

Referring to Figure 5, it is a schematic diagram of the BGP OPEN message body structure. The bytes usually occupied by each parameter field and their meanings are as follows:

Version (Version): 1 byte, the BGP version number of the sender;

Local autonomous domain (My Autonomous System): 2-byte unsigned integer, local AS number;

Hold Time: 2-byte unsigned integer, hold time suggested by the sender;

BGP identifier (BGP Identifier): 4 bytes, PE device identifier of the sender;

Optional parameter length (Optional Parameters Len): 1 byte, the length of optional parameters;

Optional parameters (Optional Parameters): variable length, optional parameters.

The beginning part of the message includes the version number Version of BGP and the autonomous system number MyAutonomous System of the sender. The hold time field Hold Time is the set seconds of the hold timer provided by the sender. The hold timer specifies the length of time that BGP neighbors consider the sender's information to be valid.

BGP Identifier is the identifier of the BGP sender. This value is determined during the handshake operation between BGP peer entities and remains unchanged between each local interface and each BGP peer.

In the embodiment of the present invention, the Optional Parameters in the OPEN message may be extended to carry the Capability notification to indicate whether the PE device supports the VPMS instance. Referring to Fig. 6, it is a schematic structural diagram of the expanded Optional Parameters in the embodiment of the present invention, wherein:

Capability code: 1 byte, used to represent the performance parameter code, selected as a value that does not conflict with the standard protocol;

Capability Length: 1 byte, the length of the performance parameter, which is the length of the capability value CapabilityValue;

Capability Value: 1 byte, for example, if it is set to 0, it indicates that VPMS is supported, otherwise it is not supported.

For the processing of the OPEN message carrying the Capability performance parameter, it is consistent with the specification recommendation (RFC, Requests for Comments) 3392.

S304, the source PE device allocates a P2MP PW label for a specific VPMS instance, generates a BGP UPDATE message, and sends it to the leaf PE device;

The BGP VPMS Network Reachability Information (NLRI, Network Layer Reach-ability Information) can be extended in the BGP UPDATE message to complete the announcement of the information required to establish the P2MP PW. With reference to Figure 7, it is the expanded BGP UPDATE report in the embodiment of the present invention Schematic diagram of the text structure, the bytes occupied by each parameter field and their meanings are as follows:

Address Family Identifier (AFI, Address Family Identifier): 2 bytes, defined as L2VPN, the value is 25;

Subsequent Address Family Identifier (SAFI): 1 byte, defined as a reserved value, for details, refer to the IANA standard.

Next hop address length: 1 byte, which identifies the network address length of the next hop in the network;

Next hop address: variable length, identifying the network address of the next hop to reach the destination;

NLRI length (NLRI length): 1 byte, identifying the length of the NLRI value;

NLRI value (NLRI value): variable length.

Referring to Fig. 8, it is a schematic diagram of the extended BGP VPMS NLRI region structure in the embodiment of the present invention, and the extended BGP VPMS NLRI region replaces the NLRI length (NLRI length) region and the NLRI value (NLRI value) region in Fig. 7 wherein:

Length (Length): 2 bytes, used to replace the NLRI length shown in Figure 7;

VPMS instance ID (VPMS Instance ID): 4 bytes, used to identify a VPMS service instance;

PE ID: 8 bytes, used to identify the source PE device;

VPMS instance label (Label for VPMS Instance): 4 bytes, used to carry the label used to identify the P2MP PW allocated by the source PE device for a specific VPMS service instance, that is, the P2MP PW label;

Point-to-multipoint pseudowire identifier (P2MP PW ID): 2 bytes, used to identify the topology of a certain P2MP PW. This value is globally unique in the network. PE devices configured with the same value belong to the same P2MP PW topology;

Reserved value (Reserved): The length is variable and used for subsequent expansion.

S305: After receiving the BGP UPDATE message, the leaf PE device reads the message information, obtains the label assigned to a certain VPMS Instance by the source PE device, and completes the establishment of the P2MP PW.

The P2MP PW is established on the P2MP PSN tunnel, and the establishment process of the P2PM PW is the process in which the source PE device on the specific P2MP PSN tunnel allocates the label used to identify the P2MP PW for the service instance on the specific P2MP PSN tunnel.

It can be seen from this embodiment that after a BGP connection is established between the source PE device and the leaf PE device, a BGP UPDATE message is generated, and the BGP UPDATE message carries the user ID allocated by the source PE device for the specific VPMS service instance. Labels for identifying P2MP PWs, so that P2MP PWs can be established. Since the method does not require static configuration, but is dynamically established, it can improve the efficiency of P2MP PW establishment; and compared with static configuration, it can improve the accuracy of configuration.

In the specific implementation, it is also possible to complete the revocation of the established P2MP PW by extending the BGP protocol. With reference to FIG. 9, it is a schematic structural diagram of the second embodiment of the method for realizing the P2MP PW in the embodiment of the present invention. The specific steps are as follows:

S901: The source PE device receives the NOTIFICATION message;

The NOTIFICATION message is mainly used when an error occurs in the leaf PE device or the leaf PE device is shut down. The message carries various error codes (such as timer timeout, etc.), including error codes, auxiliary error codes, and error information.

It can be understood that other alarm or notification messages for managing and maintaining the P2MP PW can also be used.

S902: The source PE device generates a BGP UPDATE message including withdraw (withdraw) information and sends it to the leaf PE device, withdrawing the established P2MP PW with the leaf PE device.

Referring to Fig. 10, it is a BGP UPDATE message body containing P2MP PW revocation information in an embodiment of the present invention, and AFI and SAFI jointly identify revocation information; wherein:

AFI: 2 bytes, defined as L2VPN, the value is 25;

SAFI: 1 byte, defined as a reserved value, please refer to the IANA standard for details;

VPMS Instance ID: 4 bytes, used to identify a VPMS service instance to be revoked;

Label for VPMS Instance: 4 bytes, used to identify the label of the P2MP PW to be revoked, that is, the P2MP PW label.

In specific implementation, it is also possible to complete the maintenance and management of the established P2MP PW by extending the BGP protocol. With reference to FIG. 11 , it is a flow chart of the third embodiment of the method for realizing the P2MP PW in the embodiment of the present invention. The specific steps are as follows:

S1101: The activation state of a leaf PE device changes;

A leaf PE can change from the active state to the inactive state, or from the inactive state to the active state.

S1102: The leaf PE device whose activation status has changed generates a BGP UPDATE message and sends it to the source PE device;

Refer to Figure 7 for the extended BGP VPMS NLRI in the generated BGP UPDATE message, which carries the state information of the leaf PE device whose state has changed.

S1103: The source PE device generates a BGP UPDATE message and sends it to the leaf PE device. The BGPUPDATE message carries the P2MP PW identifier allocated by the source PE device for the VMPS service instance on the specific P2MP PSN tunnel, and the leaf PE device obtains the The P2MPPW can be updated if the above P2MP PW identifier is used.

It can be seen that in this embodiment, when the activation state of a leaf PE device changes, the leaf PE device generates a label containing the P2MP PW on the PE and the topology of the P2MP PW and sends it to the source through a BGP UPDATE message. PE equipment, thereby completing the update of the P2MP PW, because the update is a dynamic update, so the maintenance cost is low.

It can be understood that, in specific implementation, when the activation state of the leaf PE device changes, it can also send a BGP UPDATE message to the network management device, and the state information of the leaf PE device is carried in the message, and the network management device The device sends a notification to the source PE device. After receiving the notification, the source PE device sends a BGP UPDATE message to the leaf PE device. The BGP UPDATE message carries the P2MP PW label allocated by the source PE device for a specific VPMS instance. , so as to realize the update of P2MP PW.

The above is described in detail by taking the implementation of P2MP SS-PW as an example. It can be understood that the method can also be applied to P2MP MS-PW. The difference from P2MP SS-PW is that the concept of S-PE (Switching Provider Edge) equipment is introduced. PE equipment establishes pseudowire connection with S-PE equipment respectively, and the end of PE equipment to PE equipment The end-to-end connection becomes a connection transferred by one or more S-PE devices, and the number of end-to-end mesh connections between PE devices is reduced through the transfer of S-PE devices.

Referring to FIG. 2 , it is a schematic diagram of a P2MP MS-PW reference model in an embodiment of the present invention. A customer edge (CE, Customer Edge) device 201 serves as an access device on the user side, and passes user service flows through an access circuit (AC, Access Circuit) 202 is sent to the terminal operator edge (T-PE, Terminating ProviderEdge) device 203; the T-PE device 203 must also support the L2VPN protocol procedure, including establishing the T-PE device 203 to the opposite end T-PE through signaling on the control plane. PE device 203 pseudo-wire connection, the data plane completes the encapsulation/decapsulation and corresponding processing functions of the layer 2 data link frame to the IP/MPLS label packet, and transmits the label packet to the opposite end T through the PW205 in the P2MPPSN tunnel 204 -PE device 203; the S-PE is used to terminate the upstream pseudowire connection with the upstream node device, and at the same time start the downstream pseudowire with the downstream node device, and establish a mapping relationship between the upstream pseudowire and the downstream pseudowire, and allocate the The mapping relationship between the upstream pseudowire and the downstream pseudowire is identified, and the pseudowire label of the upstream pseudowire is mapped to the downstream pseudowire label; PW205 refers to the connection established between the T-PE device 203 and the S-PE device 206 using L2VPN signaling , the T-PE device 203 transmits the Layer 2 data frame from the AC202 to the S-PE device 206 through the PW205, and the peer T-PE device 203 restores or regenerates the Layer 2 link frame and transmits it to the peer AC202; The PW 205 can be multiplexed in a P2MP PSN tunnel 204 and transmitted from the T-PE device 203 to the peer T-PE device 203.

The difference between implementing P2MP MS-PW and implementing P2MP SS-PW is that P2MP MS-PW is established in segments, that is, the pseudowire between the source T-PE device and the S-PE device is first established. At this time, The T-PE device is equivalent to the source PE device in the P2MP SS-PW, and the S-PE device is equivalent to the leaf PE device in the P2MP SS-PW. Specifically: a BGP connection is established between the source T-PE device and the S-PE device on a specific P2MP PSN tunnel, and the OPEN message used to establish the BGP connection can carry the indication information of whether the PE device supports a VPMS instance. - The PE device sends a BGP message to the S-PE device, which carries the P2MP PW identifier configured by the active T-PE device for a specific VPMS instance. Then establish a pseudowire between each S-PE device and the leaf T-PE device. At this time, each S-PE device is equivalent to the source PE device in the P2MP SS-PW, and the leaf T-PE device is equivalent to the P2MP SS-PW The leaf PE device in the network uses the same method as above, and then the S-PE device configures the mapping relationship between the upstream pseudowire and the downstream pseudowire to establish the P2MP MS-PW.

The case of multi-stage S-PE device transfer in the middle is similar to the case of single-stage S-PE device transfer shown in Figure 2. A P2MPSS-PW is established between one of the upstream node devices of each level and its downstream node device. The S-PE device configures the mapping relationship between the upstream pseudowire connected to it and the downstream pseudowire.

The method of establishing a P2MP MS-PW can realize a P2MP PW across operators and autonomous domains, and is convenient for cooperation among different operators.

In a specific implementation, when a leaf T-PE device or S-PE device becomes inactive, the pseudowire between the upstream node devices connected to it can be revoked. The specific method is the same as that in P2MP SS-PW. The method is similar. When a leaf T-PE or leaf S-PE becomes inactive, it can send an alarm message such as a NOTIFICATION message to the directly connected T-PE or upstream S-PE, which contains various Error codes (such as timer overtime, etc.), including error codes, auxiliary error codes, and error messages. Then the source T-PE device or the network management device generates a BGPUPDATE message containing withdraw (withdraw) information and sends it to the downstream node device step by step until the leaf T-PE device.

The maintenance of P2MP MS-PW can also be realized. For example: when the activation state of a leaf T-PE device changes, the leaf T-PE device sends a BGP UPDATE message to the upstream S-PE device, and the BGP UPDATE The message carries the state information of the leaf T-PE device, which is transmitted through the S-PE device step by step until the source T-PE device, and the source T-PE device sends The downstream S-PE device sends a BGP UPDATE message, and the BGP UPDATE message carries the P2MP PW label between the source S-PE device and the downstream S-PE device, and updates the P2MP PW. If the downstream S-PE device is directly connected to the leaf T-PE device, the downstream S-PE device sends a BGP UPDATE message to the leaf T-PE device, and the BGP UPDATE message carries the S-PE device. The P2MP PW label assigned by the PE device to the leaf T-PE device, thereby updating the P2MP PW between the S-PE device and the leaf T-PE device; if the downstream S-PE device passes other S-PE devices When a PE device is connected to a leaf T-PE device, it sends a BGP UPDATE message to the directly connected downstream S-PE device to update the P2MP PW between the two, and so on, updating the P2MP established for a specific VPMS instance step by step PW.

It can be seen that the above-mentioned revocation and maintenance of the P2MP MS-PW pseudowire is completed dynamically, so the efficiency is high, and manual configuration errors can be avoided, the accuracy of P2MP MS-PW can be improved, and the maintenance cost can be reduced at the same time.

The method for implementing P2MP in the embodiment of the present invention has been described in detail above, and the system and router device corresponding to the above method will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 12, it is a schematic structural diagram of a router in an embodiment of the present invention. The router 1200 includes: an information collection unit 1201, a connection establishment unit 1202, and a first sending unit 1203, wherein:

An information collection unit 1201, configured to collect network topology information;

A connection establishment unit 1202, configured to negotiate with downstream node devices to establish a Border Gateway Protocol BGP connection according to the collected network topology information;

The first sending unit 1203 is configured to send a BGP message to a downstream node device after the BGP connection is established, and the BGP message carries a point-to-multipoint pseudowire label allocated for a specific virtual private multicast service VPMS instance, Create a point-to-multipoint pseudowire.

It can be seen that in this embodiment, after the router establishes a BGP connection with the downstream node device, it generates a BGP UPDATE message and sends it to the downstream node device, and the BGP UPDATE message carries the information for the specific VPMS service instance The assigned P2MP PW label can establish a P2MP PW. Since the method does not require static configuration but is dynamically established, the efficiency of P2MP PW establishment can be improved; and compared with static configuration, the accuracy of configuration can be improved.

In a specific implementation, the foregoing router may also be extended, which will be described below through specific embodiments.

Referring to FIG. 13 , it is a schematic structural diagram of router 2 in the embodiment of the present invention. The difference from router 1 is that router 1300 expands the first receiving unit 1301 , the information generating unit 1302 and the second sending unit 1303 on the basis of router 1200 , wherein :

The first receiving unit 1301 is configured to receive a BGP notification NOTIFICATION message from a downstream node device;

An information generating unit 1302, configured to generate a BGP update UPDATE message containing revocation information when the first receiving unit 1301 receives the BGPNOTIFICATION message;

The second sending unit 1303 is configured to send the BGP UPDATE message generated by the information generating unit 1302, and cancel the established point-to-multipoint pseudo-wire with the downstream node device.

Wherein, the revocation information includes the point-to-multipoint pseudowire label allocated for the VPMS instance.

Same as Router 1, Router 2 establishes a point-to-multipoint pseudowire through a dynamic process, so the router has high efficiency, and can avoid manual configuration errors and improve accuracy. Moreover, the dynamic revocation of the point-to-multipoint pseudowire can be realized, so the router 2 can further improve the efficiency and accuracy of implementing the point-to-multipoint pseudowire.

On the basis of router 1 or router 2, the following extensions can also be performed to complete the maintenance of established point-to-multipoint pseudowires. The maintenance does not require manual configuration, so errors can be avoided, and configuration efficiency and accuracy can be improved.

Referring to FIG. 14 , it is a schematic diagram of the structure of the router three in the embodiment of the present invention, and is used to expand the description on the basis of the router 1200. The difference between the router 1400 and the router 1200 is that, on the basis of the router 1200, there is a second receiving unit 1401, The first label allocation unit 1402 and the third sending unit 1403, wherein:

The second receiving unit 1401 is configured to receive a BGP UPDATE message sent after the activation state of the downstream node device changes, and the BGP UPDATE message carries state information after the activation state of the downstream node device changes;

The first label allocation unit 1402 is configured to allocate a point-to-multipoint pseudowire label for a specific VPMS instance when the second receiving unit 1401 receives the BGPPDATE message;

The third sending unit 1403 is configured to send a BGP UPDATE message to the downstream node device, the BGP UPDATE message carries the point-to-multipoint pseudo-wire label allocated by the first label allocation unit 1402, and the update is related to the activation A point-to-multipoint pseudowire between downstream node devices whose status has changed.

In addition to realizing the establishment and cancellation of point-to-multipoint pseudo-wires, the router 3 can also realize the maintenance of point-to-multipoint pseudo-wires through dynamic updating, so the maintenance efficiency and accuracy can be improved.

In the above embodiment, the router can also maintain the point-to-multipoint pseudowire according to the notification information of the network management device, and a specific embodiment will be used for description below.

Referring to FIG. 15 , it is a schematic diagram of the structure of router 4 in the embodiment of the present invention. On the basis of router 1200, router 1500 extends the third receiving unit 1501, the second label assignment unit 1502 and the fourth sending unit 1503, wherein:

The third receiving unit 1501 is configured to receive a notification message from the network management device, where the notification message carries status information of the downstream node device after the activation status has changed;

The second label allocation unit 1502 is configured to allocate a point-to-multipoint pseudowire label for a specific VPMS instance when the third receiving unit 1501 receives the notification message from the network management device;

The fourth sending unit 1502 is configured to send a BGP UPDATE message to the downstream node device, the BGP UPDATE message carries the point-to-multipoint pseudowire label allocated by the second label allocation unit 1502, and the update is related to the activation A point-to-multipoint pseudowire between downstream node devices whose status has changed.

In specific implementation, the router can be applicable to different application scenarios, for example, for a point-to-multipoint single-segment pseudowire P2MP SS-PW, the above router is a source PE device, and the downstream node device is a leaf PE device; Point-to-multipoint multi-segment pseudowire P2MP MS-PW, the above router can be the source T-PE device or S-PE device, and the downstream node device is the downstream S-PE device or leaf T-PE device. If the router is an S-PE device, it is also necessary to identify the mapping relationship between the upstream PW and the downstream PW connected to the S-PE device. For an independent S-PE device, the upstream pseudowire is a point-to-point pseudowire, and the downstream pseudowire is a point-to-point pseudowire or a point-to-multipoint pseudowire.

Referring to the accompanying drawings, the system for implementing point-to-multipoint pseudowires will be described in detail through specific embodiments.

Referring to FIG. 16 , it is a schematic structural diagram of a first embodiment of a system implementing P2MP PW in the embodiment of the present invention. The system includes: a first node device 1601 and a second node device 1602, and the second node device 1602 is a downstream node device, wherein:

The first node device 1601 is configured to collect network topology information, and negotiate with the second node device 1602 to establish a Border Gateway Protocol BGP connection according to the collected network topology information; The device 1602 sends a BGP message, the BGP message carries a point-to-multipoint pseudowire label allocated for a specific virtual private multicast service VPMS instance, and establishes a point-to-multipoint pseudowire;

The second node device 1602 is configured to collect network topology information, negotiate with the first node device 1601 to establish a BGP connection according to the collected network topology information; receive the BGP message sent by the first node device 1601, and use the message from the message Obtain the point-to-multipoint pseudo-wire label assigned to a specific VPMS instance, and establish a point-to-multipoint pseudo-wire with the first node device 1601.

It can be seen that in the system described in this embodiment, after the first node device establishes a BGP connection with the second node device, it generates a BGP UPDATE message and sends it to the second node device. The P2MP PW label assigned by the specific VPMS service instance can be used to establish a P2MP PW. Since the system does not need static configuration but is dynamically established, the efficiency of P2MP PW establishment can be improved; and compared with static configuration, the configuration efficiency can be improved. Accuracy.

In a specific implementation, the above-mentioned system can be further extended, for example: the first node device 1601 can also be used to receive the BGP notification NOTIFICATION message from the second node device 1602, and generate a BGP update UPDATE message containing revocation information, And send the BGP UPDATE message to the second node device 1602, cancel the point-to-multipoint pseudowire established between the second node device 1602, and the revocation information includes: the P2MP PW label allocated for a specific VPMS instance; Correspondingly, the second node device 1602 may also be configured to send a BGPNOTIFICATION message to the first node device 1601, and when receiving the BGP UPDATE message containing the revocation information from the first node device 1601, revoke the connection with the first node device 1601. A point-to-multipoint pseudowire established between node devices 1601.

Through the above-mentioned extension, the system can realize the revoking of the established point-to-multipoint pseudowire. By realizing the dynamic revocation of the point-to-multipoint pseudowire, the system can further improve the efficiency and accuracy of realizing the point-to-multipoint pseudowire.

In specific implementation, for system maintenance, the above system can also be extended as follows:

The first node device 1601 is further configured to receive a BGP UPDATE message sent after the activation state of the second node device 1602 changes, and the BGP UPDATE message carries the state after the activation state of the second node device 1602 changes Information; assign a point-to-multipoint pseudowire label for a specific VPMS instance, and send a BGP UPDATE message to the second node device 1602, the BGP UPDATE message carries the allocated point-to-multipoint pseudowire label, and updates a point-to-multipoint pseudowire with the second node device 1602 whose activation status has changed;

The second node device 1602 is also configured to send a BGP UPDATE message to the first node device 1601 when the activation state changes, and the BGP UPDATE message carries the state information after the change of the node device; When receiving a BGP UPDATE message from a node device 1601, obtain the assigned point-to-multipoint label, and update the point-to-multipoint pseudowire with the first node device 1601.

In addition to realizing the establishment and cancellation of point-to-multipoint pseudowires, the system can also realize the maintenance of point-to-multipoint pseudowires through dynamic updating, so the maintenance efficiency and accuracy can be improved.

In the specific implementation, the system can also be maintained through the network management equipment. Referring to FIG. The system also includes a network management device 1701, wherein:

The network management device 1701 is configured to receive a notification message sent after the activation state of the second node device 1602 has changed, the notification message carries state information after the activation state of the second node device 1602 has changed, and Sending a notification message to the first node device 1601, the notification message carrying state information after the activation state of the second node device 1602 has changed;

The first node device 1601 is further configured to receive the notification message from the network management device 1701, assign a point-to-multipoint pseudowire label for a specific VPMS instance, and send a BGPUPDATE message to the second node device 1602, and the BGP UPDATE message The text carries the assigned point-to-multipoint pseudowire label, and updates the point-to-multipoint pseudowire between the second node device 1602 whose activation status has changed;

The second node device 1602 can also be used to send a notification message to the network management device 1701 when the activation state changes, and the notification message carries the state information after the activation state of the node device changes. When receiving a BGP UPDATE message from the node device 1601, obtain the assigned point-to-multipoint label, and update the point-to-multipoint pseudowire with the first node device 1601.

In specific implementation, the system described in the above-mentioned embodiments can be applied to different application scenarios, for example, for point-to-multipoint single-segment pseudowire P2MP SS-PW, the first node device in the above system is the source PE device, The second node device is a leaf PE device; and for point-to-multipoint multi-segment pseudowire P2MPMS-PW, the first node device in the above system can be the source T-PE device or S-PE device, and the second node The device is a downstream S-PE device or a leaf T-PE device. If the first node device is an S-PE device, it is also necessary to identify the mapping relationship between the upstream PW and the downstream PW connected to the S-PE device. For an independent S-PE device, the upstream pseudowire is a point-to-point pseudowire, and the downstream pseudowire is a point-to-point pseudowire or a point-to-multipoint pseudowire.

Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above-mentioned embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage medium can include: ROM, RAM, disk or CD, etc.

The method, device and system for implementing point-to-multipoint pseudowires provided by the embodiments of the present invention have been described above in detail. In this paper, specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only It is used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. In summary, this The content of the description should not be construed as limiting the present invention.

Claims (16)

1. a method that realizes point to multi-point pseudowire is characterized in that, comprising:

The source provider edge equipment is set up Border Gateway Protocol (BGP) with negotiation between the downstream node equipment and is connected according to the network topological information of collecting;

Source provider edge equipment equipment to downstream node sends the BGP message, carries the point to multi-point pseudowire label of the special-purpose multicast service VPMS of promising particular virtual example allocation in the said BGP message, sets up point to multi-point pseudowire.

2. the method for realization point to multi-point pseudowire as claimed in claim 1 is characterized in that, when said point to multi-point pseudowire arrived multiple spot single hop puppet line for point, said downstream node equipment was specially leaf Provider Edge PE equipment.

3. the method for realization point to multi-point pseudowire as claimed in claim 2 is characterized in that, further comprises:

When the source provider edge equipment receives from the BGP notice NOTIFICATION message of leaf PE equipment; Generation comprises the first bgp update UPDATE message of revocation information and sends to said leaf PE equipment; Cancel and said leaf PE equipment between the point to multi-point pseudowire set up, said revocation information comprises: be the P2MP PW label of specific VPMS example allocation.

4. the method for realization point to multi-point pseudowire as claimed in claim 2 is characterized in that, further comprises:

The 2nd BGP UPDATE message that source provider edge equipment reception is sent after changing from leaf PE device activation state carries the state information after leaf PE device activation state changes in said the 2nd BGP UPDATE message;

The source provider edge equipment sends the 3rd BGP UPDATE message to said leaf PE equipment; Carry the pseudo line tag of promising specific VPMS example allocation in said the 3rd BGP UPDATE message, the point to multi-point pseudowire between the leaf PE equipment that renewal and said state of activation change.

5. the method for realization point to multi-point pseudowire as claimed in claim 1; It is characterized in that; When said point to multi-point pseudowire arrived the multiple spot multi-segment pseudo-wires for point, said downstream node equipment was specially the pseudo-line transit point of leaf end points Provider Edge T-PE equipment or downstream S-PE equipment.

6. the method for realization point to multi-point pseudowire as claimed in claim 5; It is characterized in that; When said downstream node equipment is specially downstream S-PE equipment, further comprise: by the mapping relations sign of pseudo-line in the upper reaches of the said downstream of S-PE devices allocation, said downstream S-PE equipment connection and the pseudo-line in downstream.

7. the method for realization point to multi-point pseudowire as claimed in claim 6 is characterized in that, further comprises:

When the source provider edge equipment receives from the BGP NOTIFICATION message of leaf T-PE equipment or downstream S-PE equipment; Generation comprises a BGP UPDATE message of revocation information and sends to said leaf T-PE equipment or downstream S-PE equipment, cancel and said leaf T-PE equipment or downstream S-PE equipment between the point to multi-point pseudowire set up.

8. the implementation method of point to multi-point pseudowire as claimed in claim 6 is characterized in that, further comprises:

The source provider edge equipment receives the 2nd BGP UPDATE message that changes and afterwards send from leaf T-PE device activation state, carries the state information after said leaf T-PE device activation state changes in said the 2nd BGP UPDATE message;

The source provider edge equipment sends the 3rd BGP UPDATE message to the leaf T-PE equipment that said downstream S-PE equipment or state of activation change; Carry the pseudo line tag of promising specific VPMS example allocation in said the 3rd BGP UPDATE message, the point to multi-point pseudowire between the leaf T-PE equipment that renewal and downstream S-PE equipment or said state of activation change.

9. a router is characterized in that, comprising: the unit and first transmitting element are set up in information collection unit, connection, wherein:

Information collection unit is used for the collection network topology information;

Connect and set up the unit, be used for setting up Border Gateway Protocol (BGP) with negotiation between the downstream node equipment and being connected according to the network topological information of collecting;

First transmitting element is used for after BGP connects foundation, and equipment sends the BGP message to downstream node, carries the point to multi-point pseudowire label of the special-purpose multicast service VPMS of promising particular virtual example allocation in the said BGP message, sets up point to multi-point pseudowire.

10. router as claimed in claim 9 is characterized in that, further comprises: first receiving element, information generating unit and second transmitting element, wherein:

First receiving element is used to receive the BGP notice NOTIFICATION message from downstream node equipment;

Information generating unit is used for when receiving element receives said BGP NOTIFICATION message, generating the first bgp update UPDATE message that comprises revocation information, and said revocation information comprises: be the P2MP PW label of specific VPMS example allocation;

Second transmitting element is used to send the BGP UPDATE message that said information generating unit generates, cancel and said downstream node equipment between the point to multi-point pseudowire set up.

11. like claim 9 or 10 described routers, it is characterized in that, further comprise: second receiving element, the first label distribution unit and the 3rd transmitting element, wherein:

Second receiving element is used to receive the 2nd BGP UPDATE message that downstream node device activation state changes and afterwards sends, and carries the state information after said downstream node device activation state changes in said the 2nd BGP UPDATE message;

The first label distribution unit is used for when second receiving element receives said the 2nd BGP UPDATE message, being specific VPMS example allocation point to multi-point pseudowire label;

The 3rd transmitting element; Be used for sending the 3rd BGP UPDATE message to said downstream node equipment; Carry the point to multi-point pseudowire label that the first label distribution unit distributes in said the 3rd BGP UPDATE message, the point to multi-point pseudowire between the downstream node equipment that renewal and said state of activation change.

12. like claim 9 or 10 described routers, it is characterized in that, also comprise: the 3rd receiving element, the second label distribution unit and the 4th transmitting element, wherein:

The 3rd receiving element is used to receive the notice message of Network Management Equipment, carries the state information of the downstream node equipment after state of activation changes in the said notice message;

The second label distribution unit is used for when the 3rd receiving element receives the notice message of said Network Management Equipment, is specific VPMS example allocation point to multi-point pseudowire label;

The 4th transmitting element; Be used for sending the 4th BGP UPDATE message to said downstream node equipment; Carry the point to multi-point pseudowire label that the second label distribution unit distributes in said the 4th BGP UPDATE message, the point to multi-point pseudowire between the downstream node equipment that renewal and said state of activation change.

13. a system that realizes point to multi-point pseudowire is characterized in that, comprising: first node equipment and Section Point equipment, said Section Point equipment is downstream node equipment, wherein:

First node equipment comprises information collection unit, connects and set up the unit and first transmitting element, is used for the collection network topology information, and according to the network topological information of collecting, sets up Border Gateway Protocol (BGP) with negotiation between the said Section Point equipment and be connected; And after BGP connects foundation, send the BGP message to said Section Point equipment, and carry the point to multi-point pseudowire label of the special-purpose multicast service VPMS of promising particular virtual example allocation in the said BGP message, set up point to multi-point pseudowire;

Section Point equipment is used for the collection network topology information, according to the network topological information of collecting, sets up BGP with negotiation between the said first node equipment and is connected; Receive the BGP message that first node equipment sends, from said message, be retrieved as the point to multi-point pseudowire label of specific VPMS example allocation, the point to multi-point pseudowire between foundation and the first node equipment.

14. the system of realization point to multi-point pseudowire as claimed in claim 13; It is characterized in that; Said first node equipment; Also be used to receive BGP notice NOTIFICATION message, generate the first bgp update UPDATE message that comprises revocation information, and send a said BGP UPDATE message to said Section Point equipment from Section Point equipment; Cancel and said Section Point equipment between the point to multi-point pseudowire set up, said revocation information comprises: be the P2MP PW label of specific VPMS example allocation;

Section Point equipment; Also be used for sending BGP NOTIFICATION message to first node equipment; And receive from first node equipment comprise a BGP UPDATE message of said revocation information the time, cancel and said first node equipment between the point to multi-point pseudowire set up.

15. system like claim 13 or 14 described realization point to multi-point pseudowire; It is characterized in that; Said first node equipment; Also be used to receive the 2nd BGP UPDATE message that Section Point device activation state changes and afterwards sends, carry the state information of the Section Point equipment after said state of activation changes in said the 2nd BGP UPDATE message; Be specific VPMS example allocation point to multi-point pseudowire label; And send the 3rd BGP UPDATE message to said Section Point equipment; Carry the point to multi-point pseudowire label of said distribution in said the 3rd BGP UPDATE message, the point to multi-point pseudowire between the Section Point equipment that renewal and said state of activation change;

Said Section Point equipment also is used for when state of activation changes, sending the 2nd BGP UPDATE message to said first node equipment, carries the state information after this node device state of activation changes in said the 2nd BGP UPDATE message; When the 3rd BGP UPDATE message that receives from said first node equipment, obtain the point that distributed to the multiple spot label, upgrade and said first node equipment between point to multi-point pseudowire.

16. system like claim 13 or 14 described realization point to multi-point pseudowire; It is characterized in that; Also comprise: Network Management Equipment; Be used to receive the first notice message that Section Point device activation state changes and afterwards sends; Said first notice carries the change state information of back Section Point equipment of said state of activation in the message, and sends the second notice message to first node equipment, carries the state information after said Section Point device activation state changes in the said second notice message;

Said first node equipment; Also be used to receive the said second notice message from Network Management Equipment; Be specific VPMS example allocation point to multi-point pseudowire label; Send the 4th BGP UPDATE message to said Section Point equipment, carry the point to multi-point pseudowire label of said distribution in said the 4th BGP UPDATE message, the point to multi-point pseudowire between the Section Point equipment that renewal and said state of activation change;

Said Section Point equipment; Also be used for when state of activation changes, sending the first notice message to Network Management Equipment; Carry the state information after this node device state of activation changes in the said first notice message; When the 4th BGP UPDATE message that receives from said first node equipment, obtain the point that distributed to the multiple spot label, upgrade and said first node equipment between point to multi-point pseudowire.

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