JP4553304B2 - Network topology processing method and inter-network connection processing method - Google Patents

Description

  The present invention relates to a network topology processing method and a different network connection processing method, and in particular, a network topology processing method and a connection between different networks having different protocols in a network based on MPLS (multi protocol label switching) or GMPLS (generalized MPLS). It relates to the processing method.

  A large-scale network is configured by connecting a plurality of networks having different protocols (this network region is hereinafter referred to as a domain). When a large-scale network is configured by connecting a plurality of domains to each other, it is conceivable that the resources of the own domain that can be provided for communication with other domains are abstracted and advertised to the own domain or other domains. Also, in such a network composed of multiple domains, OIF (optical internetworking forum) UNI (user network interface) / NNI (network-network interface, network-node interface) and heterogeneous protocols such as GMPLS are linked. It is necessary to do.

  Regarding network abstraction, for example, in Patent Document 1, a plurality of existing links are virtually regarded as one link by detecting the adjacency relationship between two adjacent nodes in the network using a hello protocol. The technology is described.

  Patent Document 2 describes a PNNI topology abstraction method for calculating a cost between a pair of boundary nodes in an peer group in an ATM (Asynchronous transfer mode) PNNI network including a plurality of PNNI (Private NNI) layers. ing.

In addition, Non-Patent Documents 1 and 2 describe specifications related to OIF UNI and E-NNI, respectively, and Non-Patent Document 3 describes an architecture and specification outline regarding GMPS.
JP 9-36873 A JP 2000-69005 A User Netwark Interface (1.0) Signaling Specification, Implementation Agreement, Optical Internetworking Forum (OIF) Intra-Carrier E-NNI Signaling Specification, Implementation Agreement, Optical Internetworking Forum (OIF) E. Mannie, Generalized Multi-Protocol Label Switching Architecture Internet Draft, Internet Engineering Task Force (IETF)

  According to the technique of Patent Document 1, when there are a plurality of links between adjacent nodes, these links are virtually regarded as one link, so the number of links between two nodes can be reduced, Link state information can be reduced. However, since the topology of the network area itself, that is, the domain itself is not abstracted, when advertising the topology between domains, the advertised topology will not be too abstract. There are challenges.

  Further, according to Patent Document 2, it is possible to automatically execute PNNI network topology abstraction using a matrix update algorithm. This is based on route determination within one domain according to one policy. It does not consider the exchange of topology between domains with different policies. In addition, there is a problem that a topology in a network such as GMPLS is determined based on a flexible policy that comes from an operator's intention or a business request, and cannot be advertised outside the own network as necessary.

  Further, according to Non-Patent Documents 1 and 2, the specifications for the device that first requests the LSP to request the LSP by the UNI protocol and the specifications of the E-NNI protocol for establishing the LSP request between the domains are defined. However, there remains a problem of how to perform protocol conversion processing, LSP request message processing, and transfer method when the protocol in the domain is a different protocol such as GMPLS.

  Further, according to Non-Patent Document 3, it is necessary to transfer a signaling message for establishing an LSP to all GMPLS nodes that constitute the same layer. There is a problem that it takes a lot of time.

  Furthermore, according to Non-Patent Documents 1 to 3, when constructing an LSP across a plurality of domains, a method for distinguishing between links inside the domain and external links connecting the domains is not defined. When the same protocol such as OSPF is used between domains, there is a problem that even if it is necessary to construct an LSP within its own domain, there is a possibility of constructing an LSP via another domain. Further, when establishing a different session for each domain when constructing an LSP across a plurality of domains, there is also a problem that a node that establishes a session cannot determine its destination.

  An object of the present invention is to provide a network topology processing method capable of abstracting a network topology with necessary paths between nodes constituting the network, and advertising the paths to itself and other networks as necessary. It is in.

  Another object of the present invention is to provide an inter-network connection processing method that can transfer a message according to a different protocol at a domain boundary, and that can determine a link inside a domain and a link between domains when constructing an LSP. It is to provide.

In order to solve the above-described problem, the network topology processing method of the present invention is configured by a first step of setting an LSP between nodes of its own network that constructs an LSP across other networks , and the first step. is characterized by having a second step of abstracting the topology of its own network based on the resource information about only the link was LSP as a virtual link.

Here, prior to setting the LSP in the first step or after setting the LSP in the first step, an instruction is given that the LSP set between the nodes of the own network is an LSP straddling between other networks. be able to. Further, the resource information only needs to include bandwidth information as much as necessary for communication with another network.

  Also, the abstract topology can be advertised to other networks. Furthermore, it is also possible to advertise resource information related to LSPs that do not cross between other networks to nodes that construct LSPs only within the local network.

The inter-network connection processing method of the present invention is a cross-network connection processing method for connecting a local network that is a GMPLS protocol and another network that is an OIF UNI protocol, and is abstracted by the network topology processing method. topology have been advertised to each other, the self network node receiving the message by the OIF UNI signaling from other network, in accordance with the destination TNA included in Generalized UNI object of the message is the virtual links in the abstract topology performed links and path computation based on the topology advertised from another domain between LSP and the own and other domains configured between nodes of its own network, the session destination, and a node for accommodating the virtual link on the other hand The MPLS signaling message, by sending to impart Tunnel ID that uniquely determined to the node, is characterized by performing the conversion processing OIF UNI protocol and GMPLS protocols.

Here, the GMPLS signaling message Tunnel ID is assigned, preferably from the node of its own network which has received the message by OIF UNI signaling for transferring the direct virtual link to node accommodating the other.

Also, the time of constructing the LSP in its own network internal to configure a virtual link, in order to distinguish between links connecting between the links and the own network and other networks constituting the own network, its own network and its own network and Nodes in its own network that construct LSPs with different area numbers between other networks refer to the area numbers and preferentially use resources in the abstract topology advertised by nodes in the same area It is also preferable to perform LSP route calculation.

  According to the network topology processing method of the present invention, the topology is abstracted based only on the resources of the own network that can be used by other networks. Therefore, for operation or business reasons, the node cannot accept connections from other domains. Unnecessary information such as information about the link to reach can be omitted. In addition, other networks to which the abstract topology is advertised can know the topology in a simplified form, and the processing for communication between the networks becomes easy.

  According to the inter-network connection processing method of the present invention, when LSP establishment is requested by the OIF UNI, the GMPLS node can convert the message and then transfer the message at high speed to construct the LSP. In addition, since it is possible to distinguish between the links constituting the local network and the links connecting the local network and the local network, it is possible to construct a closed LSP inside the local network without mixing the links of the local network. become.

  The present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an example of a network to which the present invention is applied. The network 10 is connected to another network 20. Hereinafter, a network area considered as an object of abstraction is referred to as a self domain, and other network areas are referred to as other domains. A large-scale network is configured by connecting the own domain 10 and the other domain 20. For example, the own domain 10 is provided by the company A, the other domain 20 is provided by the company B, and the protocol is usually different between the own domain and the other domain. In addition to one other domain, a plurality of other domains may be connected to the own domain 10.

  When the network is an optical network, the inside of the own domain 10 is configured by devices having different switching capabilities (Swithing capabilities), that is, different layers. In FIG. 1, the layer structure is shown as Layer1 and Layer2. For example, devices such as an optical cross-connect device, a switching device that switches an optical fiber in slot units, an ADM device, and an IP router are arranged to form a layer structure such as an optical layer, a TDM layer, and an IP layer.

  The own domain 10 includes a plurality of nodes. Nodes Node1, Node2, Node3, and Node4 are nodes serving as edges of the own domain 10, and these nodes Node1, Node2, Node3, and Node4 are service nodes Node5 and 6, Node7, and Node8 for providing services to users. , Node9 is accommodated respectively. The node Node4 is a boundary node with the other domain 20, and further accommodates a boundary node of the other domain 20. Each node is connected by one or a plurality of links.

  Some of the service nodes Node5 to Node9 are terminal nodes when an LSP (Label switched path) is constructed only within the own domain 10, and communicate with the other domain 20, that is, the own and other domains. There is also a terminal node when an LSP that spans between 10-20 is constructed. The terminal node that constructs the LSP reaching the other domain 20 is technically capable of supporting not only the protocol of the own domain 10 but also the protocol of the other domain 20. The terminal node to be constructed can handle only the protocol of the own domain 10.

  In addition, for business reasons, a node that can construct an LSP reaching another domain 20 may be distinguished from a node that cannot construct it. Here, it is assumed that the service node Node5 is a terminal node capable of constructing an LSP reaching the other domain 20, and the service node Node6 is a terminal node that constructs an LSP only within the own domain 10.

  In the above configuration, if the resources related to all the links constituting the topology of the own domain 10, for example, the link bandwidth, the encoding type, and the Swithing capability are advertised to the other domain 20, In addition, for business reasons, unnecessary information such as information on links to nodes that do not accept connections from other domains 20 is also advertised, which is inappropriate.

  Therefore, in the present invention, the topology of the own domain 10 is abstracted based only on the resources of the LSP from the node that accepts the path from the other domain 20 or originates to the other domain 20 to the other domain 20. The converted topology is advertised to other domains 20.

  For example, when the node that accepts a path from the other domain 20 or transmits to the other domain 10 among the nodes of the own domain 10 is Node5, first, based on only the LSP resources from the node Node5 to the node Node4. Abstract the topology of the domain 10. This is because an LSP is constructed between the node Node1 and the node Node4 on the own domain 10 side that accommodates the service node Node5, this LSP is a virtual link, and the resources related to the link are the topology of the own domain 10 realizable.

  At this time, the LSP band constructed between the node Node1 and the node Node4 may be secured only for a band necessary for communication with the other domain 20 or a band limited for business reasons. It is also conceivable to construct a plurality of LSPs between the node Node1 and the node Node4 and to secure an appropriate ratio (100% or less) of bandwidth in each of these LSPs.

  Next, the abstract topology of the own domain 10 is advertised from the node Node 4 to the other domain 20. Prior to the LSP construction, the operator inputs a parameter indicating that the LSP to be constructed is an LSP reaching another domain 20 from the operation terminal or after the LSP is constructed, When the operator instructs the LSP to reach 20 from the operation terminal, the constructed LSP can be set as an LSP to reach another domain, and the topology of the own domain 10 can be determined based only on the resources related to the LSP. It can be abstracted and advertised to other domains 20.

  This advertisement may be performed for a node in the own domain that constructs an LSP that reaches the other domain 20. Alternatively, an LSP that can be used only within the own domain 10 may be constructed, and the topology of the LSP may be advertised to a node that constructs an LSP only within the own domain 10 such as the node Node6.

  FIG. 2 is a flowchart showing an example of the operation in the network topology processing method of the present invention. The reference numerals in the figure correspond to those in FIG. First, a path setting request (PATH) is transmitted by signaling from the node Node1 on the own domain 10 side that accommodates the service node Node5 to the node Node4. A response (RESV) to this path setting request is returned from the node Node4, whereby an LSP is constructed between the node Node1 and the node Node4.

  Next, a policy is input from the operation terminal (PC) 30. It is assumed that the input of this policy instructs the node Node1 and the node Node4 that the LSP constructed above is an LSP reaching another domain.

  By exchanging information with each other (LS update), the nodes Node1 and Node4 secure an LSP that is bidirectional and reaches the other domain 20 with a bandwidth of 100 Mbps, for example. The reserved LSP resource is advertised to the other domain 20 as a topology abstracted from the node Node4 (LS update). Thereby, the node Node5 and the nodes of the other domain 20 can know the resources of the own domain 10 that can be used when the LSP is constructed mutually.

  The node Node5 and the node of the other domain 10 can request the setting of a path between each other in consideration of the advertised resource. For example, if a node less than the reserved bandwidth is requested from the node Node5 of the own domain 10 to the node of the other domain 20, the path setting request (PATH) and its response (RESV) are used in accordance with the LSP. A path is set. The same applies to a case where a path setting from the node of the other domain 20 to the node Node5 of the own node 10 is requested.

  Next, the inter-network connection processing method of the present invention will be described. Here, a case will be described in which an LSP from Node5 to the other domain 20 is constructed with the UNI protocol between Node5 and Node1 of FIG. 1, the GMPLS protocol between the own domain and the NNI protocol between Node4 and the other domain 20.

  FIG. 3 is a flowchart showing an example of operation in the inter-network connection processing method of the present invention. First, in S31 to S34, for example, the topology of the own domain 10 is abstracted as described above, and the resource information about the virtual link is advertised. In the case of this example, a virtual link of a predetermined band is set between Node1 and Node4 (S31), and it is instructed by the advertisement type input whether the band is advertised outside or inside the own domain 10 (S32). . Here, when it is instructed to advertise inside its own domain, advertisement is made inside its own domain (S33), and when advertisement outside of its own domain is instructed, it is outside of its own domain, that is, other domains Advertisement is performed (S34).

  In a state where the virtual link is set in this way, when an LSP establishment request is sent from Node 5 to Node 1 by OIF UNI signaling via the GMPLS protocol's own domain 10 to a node in another domain 20 (S35). The Node1 (GMPLS node) that has received the message by OIF UNI signaling confirms the destination TNA information included in the Generalized UNI object of the message (S36), and according to the destination TNA information, between Node1 and Node4 of the own network 10 The path calculation is performed based on the link between the LSP (virtual link) set to "1" and the own and other domains 10, 20 and the resource information advertised from the other domain 20 (S37).

  Next, Node1 directly transmits to Node4 a GMPLS signaling message (LSP request) in which the destination of the session is the node that accommodates the virtual link on the other side, that is, Node4 (S38). At this time, Node1 assigns the uniquely determined Tunnel ID to the GMPLS signaling message and sends it out. As described above, conversion processing between the OIF UNI and GMPLS protocols is realized.

  By sending GMPLS signaling messages directly from Node1 to Node4, it is possible to establish an LSP at a high speed by eliminating the time required for checking and forwarding messages in each GMPLS node, rather than hopping all GMPLS nodes. Become.

  Node4 receives the GMPLS signaling message from Node1, and sends a signaling message (LSP creation request) with a uniquely determined Tunnel ID to the other domain 20 in accordance with the same procedure as Node1 (S39). Thereby, conversion processing between GMPLS and OIF E-NNI protocol is executed. After that, the process moves to another domain.

  Further, when an LSP is constructed within the own domain 10 in order to set a virtual link, in order to distinguish between the link constituting the own domain 10 and the link connecting the own and other domains 10 and 20, the own domain 10 It is preferable that the inside and the other domains 10 and 20 have different area numbers. As a result, a GMPLS node that constructs an LSP can construct an LSP that is closed within its own domain 10 by preferentially using resources advertised from nodes in the same area and calculating the route of the LSP. In addition, when an LSP is constructed by a plurality of sessions, a node that establishes a session can determine the boundary of the domain that is the destination of the session from the area boundary. Therefore, it is possible to construct a closed LSP inside the own domain without mixing links of other domains.

  As mentioned above, although embodiment was described, this invention is not limited to the said embodiment. For example, what distinguishes its own domain from other domains may be a range that divides the network, such as a region or AS (autonomous system). Further, the paths constructed between the nodes include all the paths included in the path as a concept, and are not limited to LSPs.

It is a block diagram which shows an example of the network to which this invention is applied. It is a flowchart which shows an example of the operation | movement in the network topology processing method of this invention. It is a flowchart which shows an example of the operation | movement in the different network connection processing method of this invention.

Explanation of symbols

10 ... own domain, 20 ... other domain, 30 ... operation terminal (PC), Node1 to Node4 ... node of own domain, Node5 to Node9 ... service node

Claims (9)

In a network topology processing method for abstracting a topology of a network composed of a plurality of nodes,
A first step of setting LSPs between nodes of the own network that constructs LSPs straddling other networks;
Network topology processing method characterized in that it comprises a second step of abstracting the topology of the first of its own network based on the LSP which is set in the resource information about only the link as a virtual link in step. An instruction that the LSP set between the nodes of the own network is an LSP that straddles between other networks is made prior to the setting of the LSP in the first step. The network topology processing method according to claim 1, wherein an LSP is set between nodes of a self-network that constructs an LSP between them. An instruction that the LSP set between the nodes of the own network is an LSP across other networks is made after setting the LSP in the first step, and between the other networks by the first step before the instruction. The network topology processing method according to claim 1, wherein an LSP is set between nodes of a local network that constructs an LSP that spans the network.   2. The network topology processing method according to claim 1, wherein the resource information includes as much bandwidth information as is necessary for communication with another network. The network topology processing method according to claim 1, further comprising a third step of advertising the abstracted topology to another network. 6. The network topology processing method according to claim 5, further comprising a fourth step of advertising resource information related to an LSP that does not cross between other networks to a node that constructs the LSP only within the own network. In a different network connection processing method for connecting a local network that is a GMPLS protocol and another network that is an OIF UNI protocol,
The topologies abstracted by the network topology processing method according to claim 1 are advertised to each other, and a node of the own network that has received a message by OIF UNI signaling from another network is included in the Generalized UNI object of the message In accordance with the destination TNA, the route calculation based on the link between the LSP and the own and other domains that are virtual links in the abstract topology and the topology advertised from other domains and the topology advertised from other domains is performed. the destination, the GMPLS signaling messages with node accommodating the virtual link on the other hand, by sending to impart uniquely determined Tunnel ID to the node, performs the conversion processing of OIF UNI protocol and GMPLS protocols This Cross-network connection process wherein the. 8. The GMPLS signaling message to which the Tunnel ID is assigned is directly transferred from a node of the own network that has received the message by OIF UNI signaling to a node that accommodates the virtual link on the other side. Network connection processing method. Wherein when building the LSP in its own network internal to configure a virtual link, in order to distinguish between links connecting between the links constituting the own network own network and other networks, its own network and its own network and other networks Nodes of the own network that construct LSPs with different area numbers refer to the area numbers and preferentially use resources in the abstract topology advertised from nodes in the same area. The inter-network connection processing method according to claim 7, wherein LSP route calculation is performed.

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