KR20010088047A - Method for setting lsp in mpls system - Google Patents

Abstract

PURPOSE: A method for setting an LSP(Label Switched Path) in an MPLS(Multi Protocol Label Switching) system is provided to efficiently set the LSP by using a previously set LSP in an MPLS network. CONSTITUTION: An egress edge(Ri) router obtains routing information to a destination IP address of a destination by a routing protocol and generates a routing table entry(100). The egress edge router transmits a request message for searching an egress point on an MPLS network to the destination ID address to an egress edge router(Re). If the egress edge router(Ri) receives egress edge node address information from the egress edge router(Re)(104), the egress edge router(Ri) reads egress edge node address information included in a response message(106) and judges whether egress edge node address information exists in egress edge router ATM address items of an LIB(Label Information Base)(108). If egress edge node address information exists in the egress edge router ATM address items of the LIB, the egress edge router reuses a previously set LSP(110). If transmission data are received from an external network(114), the egress edge node transmits data using the set LSP(116).

Description

How to set label switch path in multi-protocol label switching system {METHOD FOR SETTING LSP IN MPLS SYSTEM}

The present invention relates to a network system, and more particularly to an initialization method in a multi-protocol label switching (MPLS) system.

The explosive growth of Internet users and traffic volumes, and the commercialization of new applications and the Internet, are driving the need for Quality of Service (QoS) and service availability. Multi Protocol Label Switching (MPLS) is an ongoing standard in the Internet Engineering Task Force (IETF) to meet this need. MPLS is independent of two-layer networks, but ATM cell switching effectively supports MPLS's concept of label swapping. MPLS is now recognized as the most powerful IP-over-Asynchronous Transfer Mode (IP-over-ATM) technique in backbone networks.

The early Internet was mainly used for file transfer protocol (FTP), e-mail, and remote-login between some research institutes and universities. However, the use of the Internet has exploded due to the spread of personal computers and the emergence of the Word Wide Web. As a result, processing capacity for rapidly increasing traffic capacity is required. In addition, with the emergence of new applications such as video conferencing, there is an increasing demand for QoS functions. User groups require different service availability and QoS, and therefore services and charges.

The current Internet structure does not meet these needs. In other words, it performs three-tier routing with software, supports only the best-effort service without guarantees, and the possibilities for traffic engineering or aggregation are extremely limited. MPLS solves this problem as follows:

Combine label swapping concepts with 3 routing.

Improves the price-per-performance of 3 routing

Provides scalability through traffic aggregation

Traffic engineering can be provided by supporting new routing services.

Guarantee QoS

MPLS uses a scheme that simplifies forwarding by introducing the concept of connection-oriented on a connectionless IP network. That is, a fixed path, that is, a label switched path (LSP) from an edge node to another edge node in a high-speed switching network equipped with the MPLS function, for example, an ATM network, is set at a call setup time. Thus, the actual IP packet is delivered in the MPLS network through a preset LSP. At this time, a protocol for establishing an LSP between nodes in an MPLS network is required. IEFT proposed LDP (Label Distribution Protocol).

In FIG. 1, there are a plurality of nodes, for example, a plurality of edge router ERs and label switch routers LSRs, in the MPLS network 10. 2 shows the configuration of the LSP 12 between nodes in the MPLS network 10.

Once a particular LSP has been set up in the MPLS network 10, each edge router ER is configured to;

(1) Parse the header and set which LSP to use

(2) The packet is attached with an LSP ID in the form of a label.

When this process is completed, each node sees only the label information attached to the packet and transmits it at high speed along the LSP.

A more detailed description of the LSP configuration is as follows.

Each node performs LDP operation to establish LSPs with neighbor nodes. A particular node negotiates a label to use with its upstream and downstream neighbors for each forwarding equivalence class (FEC) it has. That is, it is determined which label to use for the LSP between the upstream node ↔ specific node (downstream node) or the specific node (upstream node) ↔ downstream node. The basic way to set up an LSP is as follows: First, the upstream proposes to the downstream to negotiate a label with each other for the LSP for a particular FCE. 3A shows the path of a label request for the LSP. The path of the label request consists of R1 → R2 → R3 → R4 → R5. The downstream node then assigns a label for that FEC and informs the upstream peer. 3b shows a path for notifying upsteam peers of labels for LSPs. The path for notifying the upstream peer is composed of R5 → R4 → R3 → R2 → R1. As a result, each node creates a table called LIB (Label Information Base) that functions as a mapping between the label representing the LSP of the link and the FEC. Whenever the neighbor information of a specific node changes, the node negotiates again with the newly recognized neighbor node to generate an LSP.

As described above, if a packet from an external network (not shown) is applied to one of the plurality of edge router ERs in the MPLS network 10 after the LSP is established by the LDP, the edge router (usually " ingress " ingress), (1) analysis of IP headers, (2) determining the LSP to use according to the destination IP address, (3) decomposing the IP packet into ATM cells, and (4) the level corresponding to the destination IP address. Is passed to peer LSR using VPI / VCI value. LSRs present on the LSP path forward packets to egress edge router ERs only by cell switching without assembling / disassembling packets. The egress edge router ER performs (1) reassembly of ATM cells, (2) IP header analysis, and (3) three-layer forwarding.

However, the prior art has the following disadvantages. When the ingress edge router detects routing information for one of the plurality of destination nodes connected to the egress edge router, the LSP is established between the ingress edge router and the egress edge router by a normal LDP procedure. When the routing information of another destination node among the destination nodes connected to the egress edge router is detected, the ingress edge router and the egress edge router are again connected to the LSP (the same as the existing LDP) by a normal LDP procedure. LSP) is set. Since the conventional technology as described above cannot detect an egress point in the MPLS network, the ingress edge router cannot transmit packet data using the LSP previously established for other destination nodes. Therefore, as described above, the conventional technology newly sets the LSP every time routing information is detected.

Accordingly, an object of the present invention is to provide a method for performing efficient LSP configuration in an MPLS network.

Another object of the present invention is to provide a method of reducing the number of unnecessary LSPs using egress point information of an MPLS network.

In accordance with the above object, the present invention provides a method for setting a label switch path in a multiprotocol label switching system, wherein an ingress edge node of the multiprotocol label switch network corresponds to an egress edge of the multiprotocol label switch network corresponding to a destination address. A first step of obtaining node address information, a second step of determining whether the egress edge node address information is registered in its information storage area, and an ingress edge node of the ingress edge node; When the egress edge node address information is registered in the information storage area, a third process of setting a label switch path corresponding to the egress edge node address information as its own label switch path is performed.

The present invention also provides a method for setting a label switch path of a multiprotocol label switching system in which a multiprotocol label switch network includes a plurality of edge nodes connected to each of an external network and a plurality of nodes located therein. Each of the four edge nodes requests the other edge node address information in the multi-protocol label switch network corresponding to the nodes in the external network to the nodes located in the protocol label switch network, and receives a response accordingly, and the address of the other edge node. The edge node receiving the information is determined whether address information of the other edge node received is registered in its information storage area, and the edge node has the other edge node address information in its information storage area. If registered, corresponding to the other edge node address information And a level switch path characterized constituted by any process, to set their label switch path.

1 is an example configuration of an MPLS network;

FIG. 2 is a diagram illustrating LSP configuration in an MPLS network; FIG.

3A is a diagram for explaining a label request for an LSP;

3B is a diagram for explaining notifying a label for an LSP;

4 is a view for explaining a method for setting an LSP in an MPLS network according to an embodiment of the present invention;

5 is a structure diagram of a LIB (Label Information Base) according to an embodiment of the present invention,

6 is a control flowchart performed by an ingress edge router according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same elements in the figures are denoted by the same reference numerals or the same reference numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

4 is a diagram for describing a method for setting an LSP in an MPLS network according to an embodiment of the present invention. Referring to FIG. 4, the MPLS network 10 includes a plurality of nodes Ri, Re, and Rc. Ri of the plurality of nodes Ri, Re, and Rc denotes an ingress edge router to which packet data (eg, packet data P1 and P2) from an external network is applied, and Re denotes a packet to an external network. Egress edge router for sending data. The edge router ERs shown in FIGS. 1-3A and B may be either the ingress edge router of FIG. 4 or the egress edge router. The nodes Rc in the MPLS network 10 refer to core routers. The core router Rc corresponds to the LSR in FIGS. 1 to 3A and b. 1 to 12 denote an LSP set between an ingress edge router Ri and an egress edge router Re, P1 and P2 denote packet data, and C denote an ATM cell. The plurality of nodes 20 and 22 are destination nodes connected to the egress edge router Re, and D1 and D2 are destination IP addresses corresponding to the nodes 20 and 22, respectively.

When the ingress edge router Ri detects routing information for the destination node 20 among the destination nodes connected to the egress edge router Re by a periodically operating routing protocol, the ingress edge router Ri is typically used. The LSP 12 is set between the egress edge routers Re by the LDP procedure. Thereafter, when the ingress edge router Ri detects routing information about the destination node 22 connected to the egress edge router Re by a periodically operating routing protocol, the ingress edge router Ri and the egress edge are typically detected. The LSP 12 is set again between the routers Re by the LDP procedure.

In the present invention, to reduce such unnecessary LSP configuration, the ingress edge router Re manages an egress point in the MPLS network 10. Each of the ingress edge routers Ri, i.e., the edge routers ERs shown in FIGS. 1 to 3a and b of FIG. 4, includes a label information base (LIB) structure as shown in FIG. 5, according to an embodiment of the present invention. Doing. 5, the LIB includes a destination IP address entry 30, a label entry 32, and an egress edge router ATM address entry 34.

6 is a control flowchart performed by the ingress edge router Ri according to an embodiment of the present invention.

The LSP setting operation according to an embodiment of the present invention will now be described in detail with reference to FIGS. 4 to 6.

The ingress edge router Ri of FIG. 4 is a routing protocol that performs periodically with routers (ie, edge router ERs and LSRs shown in FIG. 1) in the MPLS network 10, as in step 100 of FIG. 6. For example, routing information about the destination IP address D1 of the destination 20 is obtained to generate a routing table entry. Destination IP address D1 of destination 20 is " 165.213.179.0 " described in destination IP address item 30, as in the example shown in FIG. The destination IP address D2 of the destination 22 is "165.213.178.0", as in the example shown in FIG. After performing step 100 of FIG. 6, the ingress edge router Ri proceeds to step 102 of FIG. 6 by using routing information as a request message for finding an egress point on the MPLS network 10 for the destination IP address D1. Send it.

As in the example shown in Fig. 4, the request message Rq [D1] for finding the egress point is transmitted to the egress edge router Re based on routing information (1 in Fig. 4). In response, the egress edge router Re includes the egress edge node address information in the response message Rp [D1] and transmits the egress edge node address to the ingress edge router Ri as shown in Fig. 4 (2). That is, the egress point is transmitted from the egress edge router Re to the ingress edge router Ri as, for example, address information X1 of the egress edge router Re connected to the destination 20.

When the ingress edge router Ri receives the egress edge node address information X1 from the egress edge router Re in step 104 of FIG. 6, the ingress edge router Ri proceeds to step 106 of FIG. 6. The ingress edge router Ri reads the egress edge node address information X1 included in the response message in step 106 of FIG. 6 and writes the egress edge node address information to the egress edge router ATM address entry 34 of the LIB of FIG. 5. Determine if X1 exists. If the existing LSP is not configured between the ingress edge router Ri and the egress edge router Re, the egress edge node address information X1 will not exist in the egress edge router ATM address entry 34. 6, if the egress edge node address information X1 does not exist in the egress edge router ATM address entry 34 of the LIB of FIG. 5, the egress edge node address information X1 does not exist. Ri proceeds to step 112 to set the LSP by the LDP. The specific method of setting the LSP by the LDP is as described above. When the LSP is set by the LDP, as shown in FIG. 5 in the LIB according to the embodiment of the present invention, the destination IP address item 30 has the destination IP address "165.213.179.0" in the destination 20. In the label item 32, the label " 0/100 " which is the LSP ID is registered. In the egress edge router ATM address item 34, the ATM address X1 of the egress edge router Re is registered. In the label "0/100" value, "0" is a VPI value and "100" is a VCI value.

After performing step 112 of FIG. 6, the ingress edge router Ri proceeds to step 114 of FIG. 6. In step 114 of FIG. 6, the ingress edge node Ri determines whether transmission data, for example, packet data P1 or P2 shown in FIG. 4, is applied from an external network. If not, the process returns to step 100 of FIG. 6 and performs operations from that step again.

Meanwhile, after the operation as described above is performed, the ingress edge router Ri may generate routing table entries by obtaining routing information on the destination IP address D2 of the destination 22, for example, by a routing protocol periodically performed in step 100. Ingress edge router Ri sends a request message Rq [D2] to the egress edge router Re to find an egress point on the MPLS network 10 for the destination IP address D2 (step 102 of FIG. 6). ③) of 4). In response, the egress edge router Re includes the egress edge node address information X1 in the response message Rp [D2] and transmits it to the ingress edge router Ri as shown in Fig. 4 (4).

When the ingress edge router Ri receives the egress edge node address information X1 from the egress edge router Re in step 104 of FIG. 6, the ingress edge router Ri proceeds to step 106 of FIG. 6. The ingress edge router Ri reads the egress edge node address information X1 included in the response message Rp [D2] in step 106 of FIG. 6 and reads the egress edge router ATM address entry 34 of the LIB of FIG. It is determined whether edge node address information X1 exists. In this case, since the existing LSP is configured between the ingress edge router Ri and the egress edge router Re, the egress edge node address information X1 will exist in the egress edge router ATM address entry 34. When the egress edge node address information X1 is present in the egress edge router ATM address entry 34 of LIB of FIG. 5, the ingress edge router Ri proceeds to step 110.

The ingress edge router Ri reuses the preset LSP. That is, the destination IP address item 30 of the LIB of FIG. 5 is registered with the destination IP address "165.213.179.0" of the destination 20, and the label item 32 and the egress edge router ATM address item 34 corresponding thereto are registered. ) Registers a registered label " 0/100 " and an egress edge router ATM address X1 at the time of LSP setup, respectively. That is, the LSP is set without the LSP procedure by the new LDP.

Meanwhile, in step 114 of FIG. 6, if the ingress edge node Ri is applied from the external network with transmission data, for example, packet data P1 or P2 shown in FIG. send. An operation for data transmission is as described above, and a detailed operation description is omitted since it may obscure the gist of the present invention.

In the above description of the present invention has been described as an example of a router on the MPLS network, it should be understood that the router is an example included in the node on the MPLS network. In FIG. 4, the ingress edge node (router) and the egress edge node (router) are specifically deleted for convenience of description, but each of the plurality of edge nodes in the MPLS network may also be an ingress edge node, and an egress edge node. It can also be a node. Therefore, while the present invention has been described with respect to specific embodiments, it will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the equivalent of claims and claims.

As described above, the present invention uses the LSP preset in the MPLS network, thereby providing an efficient LSP setting. ATM-based MPLS systems are likely to push the limits of scalability. This is because the number of connections that can be connected simultaneously to a system is limited. Therefore, as in the embodiment of the present invention, if the egress point for a specific destination is known, all traffic through the same ingress edge node and the egress edge node can be shared in one LSP. As a result, the MPLS network is expanded. You can increase the sex.

Claims (7)

In the label switch routing method in a multi-protocol label switching system, The ingress edge node of the multi-protocol label switch network obtains egress edge node address information of the multi-protocol label switch network in correspondence with a destination address; The second edge node determines whether the egress edge node address information is registered in its information storage area; The ingress edge node may set the label switch path corresponding to the egress edge node address information as its label switch path when the egress edge node address information is registered in the information storage area of the ingress edge node. Label switch routing method characterized in that made. The method of claim 1, wherein the routing information for the destination address is determined by a routing protocol that is periodically performed before the first process. The method of claim 2, wherein the first process is Making a request for the ingress edge node to obtain address information of an egress edge node for the destination address using the routing information; And the ingress edge node receives egress edge node address information from the egress edge node. The method of claim 1, wherein the egress edge node address information is an asynchronous transmission mode address of an egress edge node. The label switch path of claim 1, wherein when the data is received from an external network after the label switch path is set, the ingress edge node transmits the received data to a destination node using the set label switch path. How to set up. In the label switch routing method of the multi-protocol label switching system, the multi-protocol label switching network is composed of a plurality of edge nodes connected to each of the external networks and a plurality of nodes located therein. Each of the plurality of edge nodes requesting other edge node address information in the multi-protocol label switch network corresponding to the nodes in the external network to nodes located in the protocol label switch network and receiving a response accordingly; The edge node receiving the address information of the other edge node is determined whether the address information of the other edge node received in the information storage area is registered; The edge node may be configured to set a label switch path corresponding to the other edge node address information as its label switch path when the other edge node address information is registered in the information storage area of the edge node. How to route the switch. The method of claim 6, wherein the edge node sets a label switch path corresponding to the other edge node address information by a label distribution protocol when the other edge node address information is not registered in the information storage area of the edge node. Label switch routing method characterized by having more.