JP2005252540A - Optical network, optical path selection method therein, and optical edge router therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical network for preventing communication interruption and an increase in processing loads in an MPLS network even if changing an optical path and a band in the optical network. <P>SOLUTION: An optical edge router 3a collects an MPLS level in the MPLS network 2a to be accommodated for distributing to an opposite optical edge router 3b via the optical network 1. The optical edge router 3b generates an MPLS transfer table for selecting the optical path based on it. And when a packet is sent to the optical edge router 3a, the optical path is selected based on the MPLS transfer table. Therefore, the optical edge router 3b can transmit packets regardless of the topology of the optical network 1, and influence of a change in the optical path and band can be avoided in communications at the side of the MPLS network. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes an optical network including a plurality of optical edge routers accommodating an MPLS (Multi-Protocol Label Switching) network, and the plurality of optical edge routers connected to each other via a plurality of optical cross-connects, and the optical network And an optical edge router in an optical network.

  In recent years, with the rapid spread of optical fiber networks, demand for IP-VPN (Internet Protocol-Virtual Private Network) and wide area LAN (Wide Area LAN) services for companies using optical fiber networks as backbone networks has increased rapidly. The IP-VPN and the wide area LAN have a configuration in which a plurality of conventional IP (Internet Protocol) networks are coupled via an optical fiber network.

  Conventionally, a TDM (Time Division Multiplexing) device and a WDM (Wavelength Division Multiplexing) device that have been used in an optical network composed of an optical fiber network have been managed by a management system completely different from the IP network. Therefore, when routing is performed or a path is established in a mixed IP network and optical network, an extra control procedure is inevitably required at the boundary portion.

  Accordingly, development of an optical IP technology for converting an optical fiber network into an IP network is being promoted with the aim of reducing such an extra control procedure. For example, the International Engineering Task Force (IETF), an international standardization organization, has previously studied a technique for establishing an optical path of a TDM / WDM channel using a signaling protocol operating in the IP layer. Then, as a result to be standardized as a result of the examination, it is compiled and disclosed as GMPLS (Generalized Multi-Protocol Label Switching) technology relating to signaling and routing protocols in an optical IP network (see Non-Patent Document 1).

By the way, MPLS (Multi-Protocol Label Switching) technology is currently used as a key technology for realizing IP-VPN and wide area LAN. The MPLS technology is described in detail in Non-Patent Document 2. In an MPLS network to which the MPLS technology is applied, a label for identifying a next transfer destination is added to a packet transferred in the network, and as a result, a path to a target transfer destination is passed to the transferred packet. Can be specified. GMPLS is a technology that extends MPLS so that it can be applied to an optical IP network.
Eric Mannie (Editor), “Generalized Multi-Protocol Label Switching Architecture” (IETF Internet Draft), [online], May 2003, IETF, [searched on February 20, 2004], Internet <URL: http: // www .ietf.org / internet-drafts / draft-ietf-ccamp-gmpls-architecture-07.txt> E. Rosen, 3 others, "Multiprotocol Label Switching Architecture" (RFC3031), [online], Jan. 2001, IETF, [searched on February 20, 2004], Internet <URL: http: //www.ietf .org / rfc / rfc3031.txt>

  However, the above prior art has the following two problems. First, when the MPLS network is accommodated in the optical network, when the optical path in the optical network is changed or the bandwidth of the optical path is changed according to the increase or decrease of the traffic amount or by a prior contract. Need to reassign labels in the new optical path. At that time, although temporarily, communication is interrupted. In the communication service for enterprises, even if it is temporary, interruption of communication is not allowed.

  Second, when the MPLS label is reassigned in the optical network portion, the correspondence relationship between the MPLS label and the IP prefix also changes, and the change also affects the MPLS network side. Therefore, when the optical path is frequently changed, reassignment of MPLS labels is frequently performed, and a large number of MPLS control messages for performing this change in the network. As a result, the processing load on the entire network increases, and the effective performance of the network decreases.

  An object of the present invention is to solve these problems of the prior art. That is, the problem of the present invention is that even if an optical path change or a bandwidth change is performed in an optical network, the MPLS network does not cause communication interruption or an increase in processing load, and the MPLS network is stably operated. An object of the present invention is to provide an optical network that can flexibly perform control such as change of an optical path.

  In order to solve the above problem, the optical network according to claim 1 includes a plurality of optical edge routers accommodating an MPLS network, and the plurality of optical edge routers are connected to each other via a plurality of optical cross-connects. An optical network that controls an optical path between a plurality of optical edge routers based on GMPLS, wherein at least one of the plurality of optical edge routers receives IP prefix information in the accommodated MPLS network. Label collecting means for collecting the included MPLS label information, and label distributing means for distributing the MPLS label information including the collected IP prefix information to at least one other optical edge router constituting the optical network, Also, MPLS label information including IP prefix information is allocated. And at least one other optical edge router that generates an MPLS forwarding table for creating an MPLS forwarding table for selecting an optical path corresponding to the distributed MPLS label information, and selects an optical path based on the MPLS forwarding table. And an optical path selection means.

  In the optical network according to claim 1, at least one optical edge router first collects MPLS label information including IP prefix information in an MPLS network accommodated by the optical edge router by a label collecting unit. Then, the MPLS label information collected by the label distribution means is distributed to other optical edge routers in the optical network. Next, the other optical edge routers receiving the distribution of the MPLS label information generate an MPLS transfer table for selecting an optical path in the optical network corresponding to the MPLS label information by the MPLS transfer table generation means. . As a result, the other optical edge routers only include the MPLS label information (including the IP prefix) of the network accommodated in the original optical edge router to which the MPLS label information has been distributed only by referring to the MPLS forwarding table by the optical path selection unit. The optical path within the optical network can be selected.

  Accordingly, when the MPLS accommodated in the optical edge router that has distributed the MPLS label information is viewed from the MPLS network accommodated in the optical edge router that has received the distribution of the MPLS label information, the topology of the optical network is hidden. Only the incoming and outgoing optical edge routers are visible. That is, the optical path route change and the optical path switch in the optical network can be realized by changing the MPLS forwarding table in the optical edge router. Therefore, it is not necessary to reassign MPLS labels in the optical network, and communication interruption does not occur even if the bandwidth of the optical path is changed due to increase or decrease in traffic volume. Further, an increase in the processing load of the MPLS control message accompanying the MPLS label reassignment is also avoided.

  Further, in the optical network according to claim 2, the label distribution means in the optical network according to claim 1 processes an extended BGP (specified by RFC 3107) in which an MPLS label and an IP prefix can be distributed. The extended BGP processing means is included.

  In the optical network according to the second aspect, as a protocol used as the label distributing means, BGP extended so that an MPLS label including IP prefix information can be carried between optical edge routers is adopted. Since BGP is a standard protocol that is generally used in IP / MPLS networks, development costs for new protocols can be saved.

  According to a third aspect of the present invention, there is provided an optical path selection method in an optical network comprising a plurality of optical edge routers accommodating an MPLS network, wherein the plurality of optical edge routers are connected to each other via a plurality of optical cross-connects. A method of selecting an optical path in an optical network that controls optical paths between a plurality of optical edge routers based on GMPLS, wherein at least one optical edge router among the plurality of optical edge routers accommodates an MPLS network A label collecting step for collecting MPLS label information including IP prefix information in the optical network, and the MPLS edge information including the IP prefix information collected by the optical edge router to at least one other optical edge router constituting the optical network. The label distribution step to be distributed and the IP prefix At least one other optical edge router that has received the distribution of MPLS label information including network information generates an MPLS forwarding table for selecting an optical path corresponding to the MPLS label information including the distributed IP prefix information. An MPLS transfer table generation step to be performed, and an optical path selection step to select an optical path based on the generated MPLS transfer table are provided.

  4. The method of selecting an optical path in an optical network according to claim 3, wherein at least one optical edge router first collects MPLS label information including IP prefix information in an MPLS network accommodated by the optical edge router. (Label collection step). Then, the collected MPLS label information is distributed to at least one other optical edge router in the optical network (label distribution step). Next, the other optical edge routers receiving the distribution of the MPLS label information generate an MPLS forwarding table for selecting an optical path in the optical network corresponding to the MPLS label information (MPLS forwarding table generation step). . Then, the optical edge router performs the optical path in the optical network based on the generated MPLS forwarding table for the label information (including the IP prefix) of the network accommodated in the original optical edge router that has distributed the MPLS label information. Can be selected.

  Accordingly, when the MPLS accommodated in the optical edge router that has distributed the MPLS label information is viewed from the MPLS network accommodated in the optical edge router that has received the distribution of the MPLS label information, the topology of the optical network is hidden. Only the incoming and outgoing optical edge routers are visible. That is, the optical path route change and the optical path switch in the optical network can be realized by changing the MPLS forwarding table in the optical edge router. Therefore, it is not necessary to reassign MPLS labels in the optical network, and communication interruption does not occur even if the bandwidth of the optical path is changed due to increase or decrease in traffic volume. Further, an increase in the processing load of the MPLS control message accompanying the MPLS label reassignment is also avoided.

  The optical path selection method in the optical network according to claim 4, wherein the label distribution step in the optical path selection method in the optical network according to claim 3 processes an extended BGP in which an MPLS label and an IP prefix can be distributed. An extended BGP processing step is included.

  In the optical path selection method in the optical network according to the fourth aspect of the present invention, BGP extended so that an MPLS label including IP prefix information can be carried between optical edge routers as a protocol used as a label distribution means. Since BGP is a standard protocol that is generally used in IP / MPLS networks, development costs for new protocols can be saved.

  An optical edge router in an optical network according to claim 5 comprises a plurality of optical edge routers accommodating an MPLS network, wherein the plurality of optical edge routers are connected to each other via a plurality of optical cross-connects, An optical edge router in an optical network that controls an optical path between a plurality of optical edge routers based on GMPLS, and a label collecting means for collecting MPLS label information including IP prefix information in the accommodated MPLS network, Label distribution means for distributing MPLS label information including the collected IP prefix information to other optical edge routers constituting the optical network, and IP prefix information distributed from other optical edge routers constituting the optical network MPLS label information including And MPLS forwarding table generating means for generating an MPLS forwarding table for selecting corresponding light path, and configured to include an optical path selection means for selecting on the basis of optical path on the MPLS forwarding table.

  An optical edge router in an optical network according to claim 5 is an optical edge router according to claim 1, wherein the optical edge router is configured to distribute MPLS label information including IP prefix information, and the distribution receiving side. And an optical edge router. By configuring the opposing optical edge routers with such edge routers, the optical network is completely hidden between the MPLS networks accommodated in both optical edge routers. Therefore, it is not necessary to reassign MPLS labels in the optical network, and communication interruption does not occur even if the bandwidth of the optical path is changed due to increase or decrease in traffic volume. Further, an increase in the processing load of the MPLS control message accompanying the MPLS label reassignment is also avoided.

  The optical edge router in the optical network according to claim 6 is an extension in which the label distribution means in the optical edge router in the optical network according to claim 5 processes an extended BGP that can distribute an MPLS label and an IP prefix. A configuration including BGP processing means was adopted.

  In the optical edge router in the optical network according to the sixth aspect, as the protocol used as the label distribution means, BGP extended so that an MPLS label including IP prefix information can be carried between the optical edge routers is adopted. Since BGP is a standard protocol that is generally used in IP / MPLS networks, development costs for new protocols can be saved.

  As described above, according to the inventions of claims 1, 3, and 5, the optical network is concealed from the MPLS label assignment in the MPLS network accommodated by the optical edge router. Therefore, in an optical network, it is possible to flexibly perform control of optical paths and wavelength and optical fiber resource allocation according to the traffic amount and the like without being related to MPLS label allocation in the MPLS network. As a result, an optical network, an optical path selection method, and an optical edge that can change an optical path or change a bandwidth without affecting communication of the accommodated MPLS network or an increase in control messages. A router can be provided. That is, even if the optical path is changed or the bandwidth is changed in the optical network, communication is not interrupted in the accommodated MPLS network, and unnecessary messages do not fly. As a result, the optical network and the MPLS network can be efficiently used, and the cost per communication capability can be reduced.

  According to the invention of claim 2, claim 4 and claim 6, the optical network, the optical path selection method and the optical edge router of the invention of claim 1, claim 3 and claim 5 are developed. Development costs can be saved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Configuration of optical network>
FIG. 1 is a diagram showing a configuration of an optical network according to an embodiment of the present invention. In FIG. 1, an optical network 1 includes optical edge routers 3a, 3b, 3c and optical cross-connects 4a, 4b, 4c, which are connected by optical fiber cables. The optical edge routers 3a, 3b, and 3c accommodate MPLS networks 2a, 2b, and 2c as separate networks from the optical network 1. In FIG. 1, the number of optical edge routers, the number of optical cross-connects, and the number of MPLS networks are set to 3, but these may be 2 or more, and are not limited to 3.

  In the specification and claims of the present invention, “the router accommodates the network” means that the router is connected to the network in a form including the network at the lower level.

  The MPLS network 2 a includes one or more MPLS routers 7 connected to the optical edge router 3 a and one or more subnets 9 connected to the MPLS router 7. Although not shown, the MPLS networks 2b and 2c have the same configuration. The MPLS network is a network to which the MPLS technology described in Patent Document 2 is applied, and a packet for identifying a transfer destination is added to a packet transferred in the MPLS network in addition to an IP address. There is a feature that is.

  In FIG. 1, it is assumed that three MPLS networks 2a, 2b, and 2c are located in different locations, and are located in a site A, a site B, and a site C, respectively. These three MPLS networks 2a, 2b and 2c constitute an MPLS network 2 integrated via the optical edge routers 3a, 3b and 3c and the optical network 1. Such a configuration of the MPLS network is a configuration often adopted in the configuration of an IP-VPN or a wide area LAN.

  Of the entire network configured as described above, the optical network 1 uses a protocol defined by GMPLS (see Non-Patent Document 1) as an optical path control protocol. According to the GPMS protocol, the optical edge routers 3a, 3b, and 3c can establish optical paths 5a, 5b, and 5c that connect each other through the optical cross-connects 4a, 4b, and 4c. With the established optical paths 5a, 5b, and 5c, the optical edge routers 3a, 3b, and 3c allow BGP (Border Gateway) for exchanging MPLS labels and IP prefix information between the MPLS networks 2a, 2b, and 2c. Protocol) peers 6a, 6b, 6c can be established.

  On the other hand, in each MPLS network 2a, 2b, 2c, a packet is transferred using a protocol defined by MPLS. Packets are also transferred between the MPLS networks 2a, 2b, and 2c. In this case, the optical paths 5a, 5b, and 5c established in the optical edge routers 3a, 3b, and 3c and the optical network 1 are transmitted. Via.

  The optical edge router 3a establishes an LDP peer 8 with an adjacent MPLS router 7 in the accommodated MPLS network 2a, and acquires an MPLS label and IP prefix information associated therewith. The MPLS label and the IP prefix information acquired in this way are distributed to the opposing optical edge routers 3b and 3c via the BGP peers 6a and 6c. Note that LDP (see Label Distribution Protocol: RFC3036) generally used in an MPLS network is used as a label allocation protocol used when establishing the LDP peer 8.

<Configuration and function of optical edge router>
The configuration and function of the optical edge router will be described below.

(Configuration of optical edge router)
FIG. 2 is a diagram showing the configuration of the optical edge router according to the embodiment of the present invention. In FIG. 2, the optical edge router 3 includes a protocol processing unit 31 for setting an MPLS label and controlling an optical path, and a transfer processing unit 32 for transferring an MPLS packet. Among these, the protocol processing unit 31 includes a GMPLS protocol processing unit 33 and an MPLS label processing unit 34.

  The GMPLS protocol processing unit 33 includes an optical network topology DB (Data Base) 313, an OSPF-TE (Open Shortest Path First-Traffic Engineering) processing unit 314, and an RSVP-TE (Resource Reservation Protocol-Traffic Engineering) processing unit. 315. The MPLS label processing unit 34 includes an MPLS signaling protocol processing unit 311, an MPLS label table 312, an extended BGP processing unit 316, and an MPLS forwarding table generation processing unit 317. The transfer processing unit 32 includes MPLS transfer processing units 321a and 321b, an MPLS transfer table 322, and an MPLS switch 323.

  Next, the function of each block constituting the optical edge router 3 will be described.

(Function of the protocol processor)
In FIG. 2, a GMPLS protocol processing unit 33 constituting the protocol processing unit 31 mainly performs control such as establishment / release of an optical path. Among them, the OSPF-TE processing unit 314 operates the OSPF-TE protocol used in GMPLS, collects topology information of the optical path 5 in the optical network 1, and stores the collected topology information in the optical network topology DB 313. To do. On the other hand, the RSVP-TE processing unit 315 operates the RSVP-TE protocol that establishes / releases an optical path by GMPLS.

  Here, the optical path is generally an optical signal path set in units of wavelength or optical fiber, but in the present invention, a TDM (SONET / SDH (Synchronous Optical Network / Synchronous Digital Hierarchy)) channel or the like is also used. Contains. The GMPLS protocol can handle wavelengths, optical fibers, and TDM channels equally.

  The MPLS label processing unit 34 mainly collects and processes MPLS labels. Among these, the MPLS signaling protocol processing unit 311 operates LDP, which is an MPLS signaling protocol, with the adjacent MPLS router 7 in the MPLS network 2a accommodated in the optical edge router 3a, for example. Then, the MPLS label and IP prefix information of the MPLS network 2a are collected by establishing the LDP peer 8 of FIG. Further, the MPLS network 2b and 2c of the other sites are notified of the MPLS label and IP prefix information to the MPLS network 2a. The MPLS label and IP prefix information of the MPLS network 2a collected here are stored in the MPLS label table 312.

  In addition, the extended BGP processing unit 316 in the MPLS label processing unit 34 operates the extended BGP protocol (RFC 3107) with the other optical edge routers 3b and 3c facing the optical edge router 3a, for example, Exchange IP prefix information and collect the information. The collected MPLS label and IP prefix information are stored in the MPLS label table 312.

  The MPLS forwarding table generation processing unit 317 in the MPLS label processing unit 34 selects an optical path corresponding to each MPLS label in the MPLS label table 312 from the optical network topology DB 313, and based on the topology information, the MPLS forwarding table. 322 data is generated. The MPLS transfer table 322 is in a form that can be referred to by the hardware of the transfer processing unit 32 when transferring an MPLS packet.

(Function of transfer processing unit)
In the transfer processing unit 32, the MPLS transfer processing units 321a and 321b perform processing for transmitting / receiving an MPLS packet and selecting an output line for the MPLS network 2 and the optical network 1, respectively. The MPLS transfer table 322 stores data referred to by the MPLS transfer processing units 321a and 321b when an output line is selected. Further, the MPLS switch 323 is a switching unit for outputting the output MPLS packet to the output line, and is controlled by the MPLS transfer processing units 321a and 321b.

(Matching with terms used in claims)
The label collection unit in the claims corresponds to the MPLS signaling protocol processing unit 311 and the MPLS label table 312 in FIG. 2, and the label distribution unit corresponds to the extended BGP processing unit 316 and the MPLS label table 312 and performs the MPLS transfer. The table generation unit corresponds to the MPLS transfer table generation processing unit 317, and the optical path selection unit corresponds to the MPLS transfer table 322 and the MPLS switch 323.

<MPLS Label Collection and Distribution Procedure>
Next, the MPLS label collected by the optical edge router described above, for example, the optical edge router (ER-A) 3a, is transferred to another optical edge router facing the optical network 1 such as an optical edge router (ER). -B) The procedure for distributing to 3b will be described.

(Configuration of MPLS label table)
FIG. 3 is a diagram showing a configuration of an MPLS label table according to the embodiment of the present invention. In FIG. 3, the MPLS label table 312 includes item fields of “input label”, “output label”, “Next Hop”, and “IP prefix”. Here, the next hop column stores the IP address of the next hop corresponding to the output label, and the IP prefix column stores the IP prefix information associated with the input label and the output label. Here, the IP prefix information is the IP address of the forwarding destination of the MPLS packet associated with the input label and the output label.

  In the present embodiment, information constituting the MPLS label table 312 is collected by operating the LDP. For example, the optical edge router (ER-A) 3a in FIG. 1 assigns an input label to the own node to the IP prefix information of the own node, and information on a pair of the input label and the IP prefix by the LDP protocol. To the neighboring router (for example, the MPLS router 7 in FIG. 1) in the MPLS network 2. Then, when viewed from the adjacent router (MPLS router 7), the notified input label becomes an output label, so that the label value is recorded in the output label column and the notified IP prefix value is recorded in the IP prefix column. The LDP notification source address is recorded in the next hop field.

(MPLS label distribution sequence)
FIG. 4 is a diagram showing a sequence in which the optical edge router collects the MPLS label table and distributes it to other optical edge routers in the embodiment of the present invention. Here, in FIG. 4, as an example, the optical edge router (ER-A) 3a establishes an optical path with the optical edge router (ER-B) 3b, and the MPLS edge 7 to the optical edge router (ER) by the LDP. -A) A sequence for distributing the MPLS label distributed to 3a to the optical edge router (ER-B) 3b via the optical network 1 is shown.

  In FIG. 4, first, an optical path 5a is established between the optical edge router (ER-A) and the optical edge router (ER-B) 3b of the optical network 1. In this case, the trigger for starting the establishment of the optical path 5a may be given manually, or may be triggered by receiving the distribution of MPLS label information from the MPLS network 2a by LDP or the like.

  When the optical edge router (ER-A) 3a starts to establish the optical path 5a, the optical edge router (ER-A) 3a first transmits a Path message of RSVP-TE, which is a GMPLS optical path establishment protocol, to the optical edge router (ER-B) 3b. (Step S1). The optical cross-connects 4a and 4b intervening in the optical network 1 sequentially receive the Path message and forward it to the next hop. Finally, the optical edge router (ER-B) 3b sends the Path message. Receive.

  Next, the optical edge router (ER-B) 3b returns a Resv message for confirming the establishment of the optical path toward the optical edge router (ER-A) 3a (step S2). The node that has received the Resv message assigns a wavelength, an optical fiber, and the like, and establishes an optical path. This path establishment sequence procedure is compliant with GMPLS.

  Next, the MPLS router 7 distributes the IP prefix information #A of the subnet 9 possessed by the MPLS router 7 to the optical edge router (ER-A) 3a using the LDP together with the MPLS label x (step S3). The optical edge router (ER-A) 3a receiving this distribution records x in the output label column of the MPLS label table 312, #A in the IP prefix column, and the IP address of the MPLS router 7 in the next hop column. The optical edge router (ER-A) 3a selects y as the input label corresponding to the IP prefix #A and records it in the input label field of the MPLS label table 312.

  Next, the optical edge router (ER-A) 3a passes through the optical path 5a between the optical edge router (ER-B) 3b previously established in the optical network, that is, through the BGP peer 6a. The label y and the corresponding IP prefix #A are distributed to the optical edge router (ER-B) 3b (step S4). Upon receiving this information distribution, the optical edge router (ER-B) 3b receives y in the output label column of its own MPLS label table 312, #A in the IP prefix column, and the optical edge router (in the next hop column). ER-A) Record the IP address of 3a. These are operations performed by the extended BGP.

  Next, the optical edge router (ER-A) 3a generates the MPLS transfer table 322 in the MPLS transfer table generation processing unit 317 based on the MPLS label table 312 generated as described above. From the optical edge router (ER-B) 3b side, since the optical path 5a corresponds to the output line, the output line is determined when the optical path 5a is selected. Here, it is assumed that the output line corresponding to the selected optical path 5a is the line # 1. Therefore, the MPLS transfer table generation processing unit 317 generates an MPLS transfer table 322 in which the output label corresponding to the IP prefix #A is y and the output line is the line # 1 in accordance with the contents recorded in the MPLS label table 312. .

  FIG. 5 shows the contents of the MPLS label table and the MPLS forwarding table obtained as a result of the MPLS label collection and distribution sequence shown in FIG. 5A shows the contents of the MPLS label table 312 of the optical edge router (ER-A) 3a, and FIG. 5B shows the MPLS label table of the optical edge router (ER-B) 3b. FIG. 5C shows the contents of the MPLS forwarding table 322 of the optical edge router (ER-B) 3b.

<Optical path selection>
When the optical edge router (ER-B) 3b transmits a packet toward the optical edge router (ER-A) 3a, the optical path 5a is designated by designating the output line # 1 based only on the MPLS forwarding table 322. Select.

  Here, as shown in FIG. 5, the contents of the MPLS label table 312 are MPLS labels assigned and acquired by BGP or LDP, and information on IP prefixes. The MPLS label table 312 does not include any information such as an optical path in the optical network 1. This means that even if the optical path topology changes, the MPLS label table 312 itself does not change.

  Since the MPLS label table 312 and the optical path 5a are associated with each other for the first time when the MPLS transfer table 322 is generated, the MPLS transfer table 322 is used when changing the optical path route, changing the bandwidth, or switching the optical path. It is only necessary to update the output line column. As a result, it is not necessary to reassign the MPLS label when the optical path is changed or the bandwidth is changed. Therefore, communication such as packet transmission / reception is not interrupted even if the optical path is changed or the bandwidth is changed. Furthermore, transmission / reception of MPLS control messages accompanying MPLS label reallocation does not occur at all. Therefore, according to the present invention, it is possible to control an optical path route change or a band change without affecting the MPLS network at all.

It is a figure which shows the structure of the optical network which concerns on embodiment of this invention. It is a figure which shows the structure of the optical edge router which concerns on embodiment of this invention. It is the figure which showed the structure of the MPLS label table which concerns on embodiment of this invention. In the embodiment of the present invention, it is a diagram showing a sequence in which an optical edge router collects an MPLS label table and distributes it to other optical edge routers. It is the figure which showed the content of the MPLS label table and MPLS transfer table which are obtained as a result of having performed the collection and distribution sequence of an MPLS label.

Explanation of symbols

1 Optical network 2, 2a, 2b, 2c MPLS network 3a, 3b, 3c Optical edge router 4a, 4b, 4c Optical cross-connect 5a, 5b, 5c Optical path 6a, 6b, 6c BGP peer 7 MPLS router 8 LDP peer 9 Subnet 31 Protocol Processing Unit 32 Transfer Processing Unit 33 GMPLS Protocol Processing Unit 34 MPLS Label Processing Unit 311 MPLS Signaling Protocol Processing Unit 312 MPLS Label Table 313 Optical Network Topology DB
314 OSPF-TE processing unit 315 RSVP-TE processing unit 316 Extended BGP processing unit 317 MPLS transfer table generation processing unit 321a, 321b MPLS transfer processing unit 322 MPLS transfer table 323 MPLS switch

Claims (6)

A plurality of optical edge routers accommodating an MPLS network, the plurality of optical edge routers being connected to each other via a plurality of optical cross-connects, and controlling an optical path between the plurality of optical edge routers based on GMPLS An optical network,
Of the plurality of optical edge routers, at least one optical edge router is:
Label collection means for collecting MPLS label information including IP prefix information in the accommodated MPLS network;
Label distribution means for distributing MPLS label information including the collected IP prefix information to at least one other optical edge router constituting the optical network;
The at least one other optical edge router is
MPLS forwarding table generating means for generating an MPLS forwarding table for selecting an optical path corresponding to MPLS label information including the distributed IP prefix information;
An optical network comprising: an optical path selection unit that selects an optical path based on the MPLS forwarding table. The optical network according to claim 1,
The optical network characterized in that the label distribution means includes an extended BGP processing means for processing an extended BGP in which an MPLS label and an IP prefix can be distributed. A plurality of optical edge routers accommodating an MPLS network, the plurality of optical edge routers being connected to each other via a plurality of optical cross-connects, and controlling an optical path between the plurality of optical edge routers based on GMPLS An optical path selection method in an optical network,
A label collecting step in which at least one of the plurality of optical edge routers collects MPLS label information including IP prefix information in the accommodated MPLS network;
A label distribution step of distributing MPLS label information including the collected IP prefix information to at least one other optical edge router configuring the optical network; and
An MPLS forwarding table generating step in which the at least one other optical edge router generates an MPLS forwarding table for selecting an optical path corresponding to MPLS label information including the distributed IP prefix information;
An optical path selection step in which an optical path is selected based on the MPLS forwarding table. An optical path selection method in an optical network. The method for selecting an optical path in an optical network according to claim 3,
The method of selecting an optical path in an optical network, wherein the label distribution step includes an extended BGP processing step of processing an extended BGP in which an MPLS label and an IP prefix can be distributed. A plurality of optical edge routers accommodating an MPLS network, the plurality of optical edge routers being connected to each other via a plurality of optical cross-connects, and controlling an optical path between the plurality of optical edge routers based on GMPLS An optical edge router in an optical network,
Label collection means for collecting MPLS label information including IP prefix information in the accommodated MPLS network;
Label distribution means for distributing MPLS label information including the collected IP prefix information to other optical edge routers constituting the optical network;
MPLS forwarding table generating means for generating an MPLS forwarding table for selecting an optical path corresponding to MPLS label information including IP prefix information distributed from other optical edge routers constituting the optical network;
An optical edge router in an optical network, comprising: an optical path selection unit that selects an optical path based on the MPLS forwarding table. The optical edge router in the optical network according to claim 5,
The optical edge router in the optical network, wherein the label distribution means includes an extended BGP processing means for processing an extended BGP in which an MPLS label and an IP prefix can be distributed.

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