JP2004193644A - Router and path setting method in mpls, and network - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To relieve a load of a CPU of a router, to reduce a path setting time in the case of setting many paths of a multi protocol label switching (MPLS) and to decrease the capacity of a memory mounted on the router. <P>SOLUTION: Information required to create an MPLS transfer table used for transferring labeled packets of the MPLS is advertised using a routing protocol resulting from expanding a routing protocol and the MPLS transfer table is created on the basis of the information advertised by the routing protocol. Since the paths of MPLS can be set without using a signaling protocol, the load imposed on the CPU of the router and the path setting time can be reduced when setting many paths. Further, since it is not required to install the signaling protocol in each router, the capacity of the memory mounted on each router can be reduced. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for setting a path or a connection accommodated in a communication network. INDUSTRIAL APPLICABILITY The present invention is applied to an MPLS (Multiprotocol Label Switching) network that realizes packet transfer in a communication network by assigning a fixed-length label to a packet and determining a packet transfer route.
[0002]
[Prior art]
In recent years, due to the rapid spread of the Internet and LANs, data traffic including IP traffic has increased exponentially. In order to cope with an increase in traffic, a mechanism for providing high-speed IP packet transfer and high-level service in a backbone network is required. In order to respond to such a request, MPLS has been proposed so far.
[0003]
MPLS assigns a fixed-length label to a packet to be transferred, and based on the label, each node in the communication network determines a transfer route. By introducing this MPLS into an IP backbone network, high-speed IP transfer and advanced traffic engineering can be performed.
In order to transfer a packet in an MPLS network, it is necessary to set a path in advance. To do this, network topology information is collected by a routing protocol, and an MPLS signaling protocol such as CR-LDP or RSVP-TE is used. (See, for example, Non-Patent Documents 1, 2, and 3).
[0004]
[Non-patent document 1]
Takashi Miyamura, Takashi Kurimoto, Michihiro Aoki, "A Scalable Multipath Algorithm in Hierarchical MPLS Networks", Proc. of WTC / ISS2002.
[Non-patent document 2]
R. Coltun, "The OSPF Opaque LSA Option", IETF RFC 2370.
[Non-Patent Document 3]
B. S. Davie and Y. Rekhter, "MPLS: Technology and Applications", Morgan Kaufmann Publisher, 2002.
[0005]
[Problems to be solved by the invention]
Normally, the value of the MPLS label used in each link is basically not limited as long as it is a value unique to the link, and is determined between the facing routers using a signaling protocol.
[0006]
FIG. 12 is a diagram showing a configuration example of a network for explaining a conventional example. For example, consider a case where the router 1 transmits packets to the routers 3 and 4 using MPLS as shown in FIG. The router 2 determines whether the destination of the packet received from the router 1 is the router 3 or the router 4 by looking at the label. For this reason, it is necessary to determine the value of each label and the destination in advance between the router 1 and the router 2 using a signaling protocol or the like. In MPLS, signaling is indispensable for setting a path.
[0007]
However, in a large-scale MPLS network accommodating a large number of paths, a large amount of signaling messages are generated at the time of setting a path, so that there is a problem that a CPU load on a router increases and a path setting time increases.
[0008]
Further, since most of the CPU resources of the router are consumed by the signaling protocol, there is a problem that other protocols and processing such as device management cannot be performed.
[0009]
In addition, since the routing protocol and the signaling protocol need to be constantly operated, there is a problem in that the required processing power and memory capacity of the CPU are large.
[0010]
The present invention has been made in such a background, and since it is possible to set MPLS paths without using a signaling protocol, it is possible to reduce the load on the CPU of a router when setting many paths. It is an object of the present invention to provide a router, a path setting method, and a network that can reduce the amount of memory installed in a router because it is not necessary to implement a signaling protocol in each router, and to shorten a path setting time. I do.
[0011]
[Means for Solving the Problems]
According to the present invention, the routing protocol is extended, and information necessary for creating an MPLS forwarding table used for forwarding MPLS labeled packets using the routing protocol is advertised, and MPLS forwarding is performed based on the information advertised by the routing protocol. It is characterized in that a table is created.
[0012]
That is, a first aspect of the present invention is a router installed in an MPLS network, and a feature of the present invention is that advertisement information in a routing protocol is used to determine a label value at each hop in an MPLS path. There is a means for adding information to be used.
[0013]
The adding means may include means for adding information capable of identifying an adjacent router and information capable of identifying a port of the own router connected to the adjacent router to advertisement information in a routing protocol, or Means for adding, to the advertisement information in the routing protocol, information capable of identifying the adjacent router, information capable of identifying the own router in the network, and information capable of identifying the port of the own router connected to the adjacent router. It is desirable to provide.
[0014]
It is desirable to have a means for creating an MPLS transfer table in which the correspondence between the destination address and the MPLS label is recorded based on the advertisement information of the own device.
[0015]
As an example of the MPLS label, by including information capable of identifying the port, it is possible to recognize, for example, a port number of a router that passes to reach a target destination address. Alternatively, as an example of the MPLS label, by including information capable of identifying a router in a network and information capable of identifying the port, for example, a router that passes to reach a target destination address and a The port number can be recognized.
[0016]
In the former example, since the destination address and the port number for going there can be recognized, the MPLS path can be set for the time being. In the latter example, since the router can be recognized in addition to the destination address and the port number for going there, if a labeled packet is incorrectly distributed to the wrong router, this can be detected.
[0017]
For example, means for selecting a label value at each hop from the start point to the end point of the MPLS path with reference to the MPLS forwarding table, means for stacking the label value at each hop in a packet transferred from the start point in multiple stages Means for receiving the packet, determining a destination route based on the label value at the highest level of the label values stacked in multiple stages, deleting the label value, and transferring the packet to the next hop destination router Thereby, packet transfer by MPLS can be realized.
[0018]
Means for advertising that the own router has means for creating the MPLS forwarding table prior to advertising information necessary for path setting by a routing protocol, and means for creating the MPLS forwarding table based on the advertisement. If the means for adding the information used to determine the label value at each hop in the MPLS path by the means for adding to the advertisement information in the routing protocol for the router confirmed to have Since routers having capability and routers having no capability can be distinguished and invalid advertisement information can be eliminated, efficient advertisement can be performed.
[0019]
Further, when there are two or more paths between the start point and the end point of the MPLS path, the means for creating the MPLS forwarding table includes a plurality of MPLS labels corresponding to one destination address based on the other advertisement information. A means for creating an MPLS forwarding table that records the correspondence of the plurality of MPLS labels, and a means for switching one of the plurality of MPLS labels to the active state and the other to the standby state in accordance with the occurrence of the failure, thereby bypassing the failure location. Since packet transfer can be performed by the route, a highly reliable MPLS network can be realized.
[0020]
A second aspect of the present invention is a path setting method in an MPLS network, which is characterized in that information used for determining a label value at each hop in an MPLS path is included in advertisement information in a routing protocol. There is a place to add.
[0021]
For example, information that can identify an adjacent router and information that can identify a port of the own router connected to the adjacent router are added to advertisement information in a routing protocol, or information that can identify an adjacent router is Then, information for identifying the own router and information for identifying the port of the own router connected to the adjacent router are added to the advertisement information in the routing protocol.
[0022]
It is desirable to create an MPLS forwarding table that records the correspondence between the destination address and the MPLS label based on the other advertisement information.
[0023]
At this time, for example, the MPLS label includes information capable of identifying the port, or the MPLS label includes information capable of identifying a router in the network and information capable of identifying the port.
[0024]
The label value at each hop from the start point to the end point of the MPLS path is selected with reference to the MPLS forwarding table, the label value at each hop is stacked in a packet transferred from the start point in multiple stages, and the packet is received and multi-staged. If the destination route is determined by the label value at the highest level of the label value stacked on the router, the label value is deleted, and the packet is transferred to the next hop destination router, the packet transfer by MPLS is realized. Can be.
[0025]
In addition, prior to advertising information necessary for path setting by a routing protocol, the router advertises that the own router has the ability to create the MPLS forwarding table, and has the ability to create the MPLS forwarding table by the advertisement. If the information used to determine the label value at each hop in the MPLS path is added to the advertisement information in the routing protocol for the routing that has confirmed the above, invalid advertisement can be eliminated, and efficient advertisement can be performed. be able to.
[0026]
When two or more paths exist between the start point and the end point of the MPLS path, an MPLS transfer table that records a correspondence relationship between a plurality of MPLS labels corresponding to one destination address based on own and other advertisement information is stored. By creating one of the plurality of MPLS labels and using the other as a backup in response to the occurrence of a failure, a route bypassing the failure location can be quickly set, and a highly reliable MPLS network can be created. Can be realized.
[0027]
A third aspect of the present invention is an MPLS network including the router of the present invention.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
A router according to an embodiment of the present invention will be described with reference to FIGS. 1, 3, 7, and 11. FIG. FIG. 1 is a block diagram of the router of the present embodiment. FIG. 3, FIG. 7, and FIG. 11 are diagrams showing examples of the configuration of the MPLS forwarding table of the present embodiment.
[0029]
This embodiment is a router installed in an MPLS network. The feature of this embodiment is that the advertisement information (FIG. 13) in the routing protocol transmitted from the advertising unit 11 shown in FIG. In which an MPLS information adding unit 12 for adding information used for determining a label value at each hop is provided. FIG. 2 shows the contents of this advertisement.
[0030]
As shown in FIG. 3, the MPLS information adding unit 12 adds information capable of identifying an adjacent router and information capable of identifying a port of the own router connected to the adjacent router to the advertisement information in the routing protocol. Alternatively, as shown in FIG. 7, the MPLS information adding unit 12 can identify the information that can identify the adjacent router, the information that can identify the own router in the network, and the port of the own router that is connected to the adjacent router. Is added to the advertisement information in the routing protocol.
[0031]
That is, an MPLS transfer table creating unit 13 that creates an MPLS transfer table 14 that records the correspondence between destination addresses and MPLS labels as shown in FIGS. 3 and 7 based on own and other advertisement information is provided. As shown in FIG. 3, the MPLS label includes a port number as information for identifying a port. Alternatively, as shown in FIG. 7, the MPLS label includes information capable of identifying a router and information capable of identifying a port in a network.
[0032]
MPLS packet generation for selecting a label value at each hop from the start point to the end point of the MPLS path with reference to the MPLS transfer table 14 and stacking the label value at each hop in a packet transferred from the start point in multiple stages MPLS that receives the packet, determines the destination route with the label value at the highest level of the label values stacked in multiple stages, deletes the label value, and transfers the packet to the next hop destination router A packet processing unit 16.
[0033]
In addition, the MPLS information adding unit 12 uses the advertising unit 11 to advertise that the own router has the MPLS transfer table creating unit 3 before advertising the information necessary for path setting by the routing protocol (this is called a capability advertisement). Then, the MPLS information adding unit 12 adds the information used for determining the label value at each hop in the MPLS path to the advertisement information in the routing protocol for the router that has confirmed that the router has the MPLS forwarding table creating unit 13 by the capability advertisement. I do.
[0034]
Further, when there are two or more paths between the start point and the end point of the MPLS path, the MPLS transfer table creator 13 sends one destination address to one destination address as shown in FIG. The MPLS packet generation unit 15 creates an MPLS forwarding table in which the correspondence between a plurality of corresponding MPLS labels (primary and secondary) is recorded, and the MPLS packet generation unit 15 sets one of the plurality of MPLS labels as active and the other as a spare to generate a failure. Switch according to.
[0035]
Hereinafter, the present embodiment will be described in more detail.
[0036]
In a normal routing protocol, as shown in FIG. 13, the advertising unit 11 has an address of a router for advertising information, an IP address (or router ID) of an interface of a router to which the advertising unit 11 is connected, and a cost (distance) to the router. Advertise information that contains
[0037]
In the present embodiment, as shown in FIG. 2, in addition to the information that the advertisement unit 11 has conventionally advertised, the MPLS information addition unit 12 uses the MPLS information addition unit 12 to determine the physical number inside the router such as the port number and line card number of the connected router. Information is encoded into the value of the MPLS label and advertised. That is, the port number or line card number of each router is associated with the value of the MPLS label on a one-to-one basis. This information is advertised when there is a change in the connection configuration of the own router as in the case of a normal OSPF.
[0038]
Upon receiving the message including the above information, the MPLS forwarding table creator 13 of each router creates the MPLS forwarding table 14 based on the message. FIG. 3 is an example of the MPLS transfer table 14. As shown in FIG. 3, the MPLS transfer table creator 13 creates a table in which destination addresses of packets are associated with labels to be assigned.
[0039]
A method of creating the MPLS transfer table 14 will be described. First, the MPLS transfer table creation unit 13 creates a topology of the entire network using a normal routing protocol, and specifies a router that passes to the destination using a shortest path calculation algorithm such as Dijkstra algorithm. Next, a port number to be passed is obtained based on the advertised information.
[0040]
For example, consider an example in which the router 1 creates the MPLS forwarding table 14 addressed to the destination address A in the case of the network configuration as shown in FIG. First, a router that passes is obtained by using the shortest path calculation algorithm. Next, a label to be given is specified based on the information advertised by each router. In this case, it passes through the router 2 and the router 3 between the router 1 and the address A. The port 3 of the router 2 is connected to the router 3, and the router 3 is connected to the address A through the port 2. The router 1 creates the MPLS forwarding table 14 by arranging the label values close to the destination address in order. In this case, since the port passes through port 3 and port 2 in this order, the label values in the MPLS transfer table 14 corresponding to the address A are 3 and 2 as shown in FIG.
[0041]
FIG. 5 is an example of a labeled packet to be transferred. When a packet addressed to the address A arrives at the router 1, the MPLS packet generation unit 15 first searches the MPLS forwarding table 14, confirms that label values to be assigned are 3 and 2, and , Two labels of label values 3 and 2 are provided in multiple stages.
[0042]
Next, the router 1 sends the labeled packet to the router 2. The MPLS packet processing unit 16 of the router 2 that has received the labeled packet obtains the port number of the own router to be output based on the value of the label at the highest level, and then deletes (Hops) the highest label. And sends the packet to the output destination port.
[0043]
Next, when the router 3 receives this packet, the MPLS packet processing unit 16 similarly obtains the port number of the output destination from the highest label, deletes this label, and outputs the port number to the output destination port. Thus, the packet is transmitted from the router 1 to the network to which the address A belongs.
[0044]
Here, as a more specific embodiment, an example in which the present invention is implemented using a link state type protocol such as OSPF and IS-IS will be described. Here, a network in which OSPF operates is particularly described, but the present invention is also applicable to a network in which other routing protocols such as IS-IS, RIP, and BGP operate.
[0045]
OSPF is operating at each router in the network. When each router is connected by a link, OSPF adjacency is established through the OSPF neighbor discovery stage, and each router learns the network topology. Then, an IP transfer table of the IP packet is created based on this.
[0046]
After the above series of processing is completed, the router capable of distributing labels by OSPF uses Opaque LSA specified in RFC2370 of IETF, and determines that the own router has the capability of distributing labels using OSPF. Advertising is performed by the advertising unit 11. Here, the Link-state type of the Opaque LSA to be used is “9”, that is, the link local scope, and only the adjacent router is advertised. This is to reduce the amount of OSPF control messages circulating in the network by limiting the range of advertisement. However, in the case of a small network, the advertisement may be advertised in the entire area to which the own router belongs with an area local scope having a link-state type of “10”.
[0047]
Through the above process, the MPLS information adding unit 12 creates a list of routers having the capability of distributing labels by OSPF among the adjacent routers. Next, the MPLS information adding unit 12 of each router creates advertisement information necessary for setting the MPLS. Basically, it advertises information about the port numbers connected to the routers included in the created list of routers having label distribution capability. Specifically, the router advertises an internal identifier or the like that is used only inside the router capable of specifying the port. As the internal identifier, an interface number of MIB (Management Information Base), a tag number of an internal header used for switching, or the like can be used. The information to be ultimately advertised includes at least the following:
[0048]
-Router ID of adjacent router with label distribution capability or I of interface
P address
・ Link cost of connected link
-Label information (an internal identifier that can identify the connected port)
Here, the label of the MPLS is 20 bits, but it is possible to use all 20-bit ports for encoding an internal identifier that can be specified. However, the upper few bits (for example, 8 bits) of the 20 bits are used in the network. Information that can identify the own router (hereinafter, referred to as a router identifier) may be encoded, and an internal identifier that can identify a port may be encoded with the remaining bits (for example, 12 bits). Here, as for the information for identifying the router in the network, the network operator assigns a unique value in the network to each router in advance.
[0049]
By including information for identifying a router and information for identifying a port together in the MPLS label in this way, if a labeled packet is incorrectly distributed for some reason, the incorrectly distributed destination router differs from its own router. Since the router identifier code is attached, an erroneous delivery destination is detected, and appropriate processing such as discarding the corresponding packet becomes possible.
[0050]
Advertisement information including the router ID and label information of an adjacent router having the label distribution capability (hereinafter, referred to as label extended LSA) is advertised throughout the OSPF area to which the own router belongs. As with the normal OSPF, when a change occurs in the neighboring configuration of the own router, information including the above-described label information is advertised.
[0051]
Upon receiving the message including the above information, the MPLS transfer table creation unit 13 of each router creates an MPLS transfer table 14 necessary for transferring the MPLS packet based on the message. FIG. 7 is an example of the MPLS forwarding table 14 of the MPLS packet of the router 1 in the network of FIG. As shown in the figure, each router in the network creates an MPLS forwarding table 14 in which the destination address of the packet and the label to be assigned are associated.
[0052]
FIG. 8 is a processing flow that summarizes a series of processes up to the creation of the MPLS transfer table. That is, the MPLS information adding unit 12 establishes a routing protocol adjacency based on an advertisement in the routing protocol from another router (step 1). Subsequently, the advertisement unit 11 advertises that it has a label distribution capability (step 2). This advertisement may be performed by the advertisement unit 11 based on an instruction from the MPLS information addition unit 12, or may be performed autonomously by the advertisement unit 11. The MPLS information adding unit 12 creates a list of routers having label distribution capability among the neighboring routers (step 3), and adds a label to be attached to the router having label distribution capability in addition to the normal advertisement information. Advertise information (step 4). Upon receiving the link state advertisement including the label information from the adjacent router, the MPLS transfer table creation unit 13 creates the MPLS transfer table 14 based on the link state advertisement (step 5).
[0053]
Hereinafter, a specific example of a method of creating the MPLS transfer table 14 will be described. First, the MPLS transfer table creation unit 13 creates a topology of the entire network using a normal routing protocol, and specifies a router that passes to the destination using a shortest path calculation algorithm such as Dijkstra algorithm. Next, based on the advertised information, a label value of a label used for transfer in each router passing through is determined.
[0054]
Router 1 receives destination IP address 10.8. Consider an example in which an MPLS transfer table 14 addressed to / 16 is created. Using the shortest path calculation algorithm, a router that passes from the own router to the destination address is specified. Basically, the route that passes is the same as the route selected by the OSPF, but explicit route specification that specifies a router that passes through the route is also possible.
[0055]
Next, an MPLS label to be assigned is determined based on the label extension LSA advertised by each router. In this case, it passes through the router 2 and the router 3 between the router 1 and the destination address. The port 3 of the router 2 is connected to the router 3, and the router 3 is connected to the router 4 through the port 5. The router 1 creates the MPLS forwarding table 14 by arranging the label values close to the destination address in order. In this case, the MPLS transfer table is “2: 3, 3: 5” as shown in FIG. Here, one MPLS label is represented by “2: 3”. In this example, a part before “:” is a router identifier of information for identifying a router, and a part after “:” is a port identifier for identifying a port. . In the example, the label value is described in decimal notation. However, when the label value is actually given as a label, each value is converted into a binary number and the label is given. From the beginning, it is also possible to create the MPLS transfer table 14 in a binary number. When only the information for identifying the port number that passes through the label is placed, the label value for the destination address is “3,5”. By such a procedure, each router determines a label to be given to each destination IP address, and completes the MPLS forwarding table 14. The router in which the MPLS transfer table 14 is completed can transfer the MPLS packet.
[0056]
Next, a method of transferring an MPLS packet in each router will be described. FIG. 9 shows that the destination address 10.8. / 16 is an example of a labeled packet to be transferred. When a packet addressed to the destination address arrives at the router 1, the MPLS packet generator 15 first searches the MPLS forwarding table 14 and finds that the label values to be assigned are "3: 5" and "2: 3". After confirming that there is a packet, the labels of the label values “3: 5” and “2: 3” are sequentially stacked and added to the arrived packet.
[0057]
Next, the router 1 transmits the labeled packet to the router 2. The MPLS packet processing unit 16 of the router 2 that has received the labeled packet searches the label value (2: 3) at the highest level, and confirms from the information of the router identifier that the packet passes through the own router. Then, the port number to output the output port is determined from the port identifier. The top label is deleted (Hop), and the packet is transmitted to the output destination port.
[0058]
Next, when the router 3 receives this packet, the MPLS packet processing unit 16 similarly confirms from the highest label value (“3: 5”) that the packet should pass through its own router, and then outputs the packet. After obtaining the previous port, deleting this label, and outputting to the corresponding port. In this way, the destination IP address 10.8. The packet is transmitted to the network to which the / 16 belongs.
[0059]
Next, consider a case in which a failure such as a link failure or a router failure has occurred in the network. As shown in FIG. 10, the IP address 10.8. Consider an example in which a packet is transferred to a / 16 network using MPLS. In the ordinary method, after the occurrence of a failure, the topology information is learned again by the OSPF, and the MPLS forwarding table of the MPLS is created based on the topology information. This problem is solved by the following method.
[0060]
The destination address has two routes, a route passing through the router 3 and a route passing through the router 2 and the router 4. The MPLS transfer table creation unit 13 obtains a label value for each path, and creates an MPLS transfer table 14 having label values of two MPLS paths for one address in advance as shown in FIG. The MPLS packet generation unit 15 normally attaches an MPLS label of the primary label value “3: 5” via the router 3 having a lower cost to the destination and transmits the label.
[0061]
When any failure occurs on the primary path and the information is transmitted to the router 1, the MPLS packet generation unit 15 of the router 1 that has received the failure information sets the secondary label “2: 1” that can communicate normally. , 4: 2 ", and transfer on this route.
[0062]
The advantage of this path switching method is that by creating a label value for a backup path for a normal transfer path in advance, communication can be restarted immediately after a failure occurs.
[0063]
【The invention's effect】
As described above, according to the present invention, MPLS paths can be set without using a signaling protocol. Therefore, when a large number of paths are set, the load on the router CPU can be reduced and the path setting time can be reduced. It can be shortened. Further, since it is not necessary to implement a signaling protocol in each router, the amount of memory installed in the router can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram of a router according to an embodiment.
FIG. 2 is a diagram showing an example of advertisement information of a routing protocol in the embodiment.
FIG. 3 is a diagram illustrating a configuration example of an MPLS forwarding table according to the embodiment;
FIG. 4 is a diagram illustrating an example of a network configuration according to the embodiment;
FIG. 5 is a diagram illustrating an example of a labeled packet according to the embodiment;
FIG. 6 is a diagram illustrating an example of a network configuration according to the embodiment;
FIG. 7 is a diagram illustrating a configuration example of an MPLS forwarding table according to the embodiment;
FIG. 8 is a flowchart showing a processing flow of the embodiment.
FIG. 9 is a diagram illustrating an example of a labeled packet according to the embodiment;
FIG. 10 is a diagram illustrating a configuration example of a network according to the embodiment;
FIG. 11 is a diagram illustrating a configuration example of an MPLS forwarding table according to the embodiment;
FIG. 12 is a diagram showing a configuration example of a network for explaining a conventional example.
FIG. 13 shows advertisement information of a conventional routing protocol.
[Explanation of symbols]
1-4 router
11 Advertising Department
12 MPLS information adding unit
13 MPLS transfer table creation unit
14 MPLS forwarding table
15 MPLS packet generator
16 MPLS packet processing unit

Claims (19)

In a router installed in an MPLS (Multi Protocol Label Switching) network,
A router comprising means for adding information used for determining a label value at each hop in an MPLS path to advertisement information in a routing protocol. 2. The apparatus according to claim 1, wherein the adding unit includes a unit that adds information capable of identifying an adjacent router and information capable of identifying a port of the own router connected to the adjacent router to advertisement information in a routing protocol. Router. The adding means adds, to the advertisement information in the routing protocol, information that can identify the adjacent router, information that can identify the own router in the network, and information that can identify the port of the own router connected to the adjacent router. 2. The router according to claim 1, further comprising: 4. The router according to claim 2, further comprising means for creating an MPLS forwarding table in which a correspondence between the destination address and the MPLS label is recorded based on the advertisement information of the router. The router according to claim 2, wherein the MPLS label includes information capable of identifying the port. The router according to claim 3, wherein the MPLS label includes information capable of identifying a router in the network and information capable of identifying the port. Means for selecting a label value at each hop from the start point to the end point of the MPLS path with reference to the MPLS forwarding table;
Means for stacking the label value at each hop in a packet transferred from the origin in multiple stages,
Means for receiving the packet, determining a destination route based on the label value at the highest level of the label values stacked in multiple stages, deleting the label value, and transferring the packet to the next hop destination router. The router according to claim 1. Means for advertising that the own router has means for creating the MPLS forwarding table prior to advertising information necessary for path setting by a routing protocol,
Means for adding information used for determining a label value at each hop in the MPLS path by means for adding the advertisement information to the advertisement information in the routing protocol for the router, which has been confirmed to have the means for creating the MPLS forwarding table by the advertisement. The router according to claim 1 or 4, further comprising: When there are two or more paths between the start point and the end point of the MPLS path,
The means for creating the MPLS forwarding table includes means for creating an MPLS forwarding table that records a correspondence relationship between a plurality of MPLS labels corresponding to one destination address based on own and other advertisement information,
5. The router according to claim 4, further comprising means for switching any one of the plurality of MPLS labels as active and setting the other as standby according to the occurrence of a failure. In a path setting method in an MPLS (Multi Protocol Label Switching) network,
A path setting method characterized by adding information used for determining a label value at each hop in an MPLS path to advertisement information in a routing protocol. The path setting method according to claim 10, wherein the information that can identify the adjacent router and the information that can identify the port of the own router connected to the adjacent router are added to the advertisement information in the routing protocol. 11. The advertising information in the routing protocol according to claim 10, wherein information for identifying the adjacent router, information for identifying the own router in the network, and information for identifying the port of the own router connected to the adjacent router are added to the advertisement information in the routing protocol. Path setting method. The path setting method according to claim 11, wherein an MPLS transfer table is created in which a correspondence between a destination address and an MPLS label is recorded based on other advertisement information. 14. The path setting method according to claim 11, wherein the MPLS label includes information capable of identifying the port. 14. The path setting method according to claim 12, wherein the MPLS label includes information capable of identifying a router in the network and information capable of identifying the port. Selecting a label value at each hop from the start point to the end point of the MPLS path with reference to the MPLS forwarding table;
The packet value transferred from the origin is stacked with the label value at each hop in multiple stages,
16. The method according to claim 10, further comprising: receiving the packet, determining a destination route based on a label value at the highest level of the label values stacked in multiple stages, deleting the label value, and transferring the packet to a next hop destination router. Path setting method described in any of the above. Prior to advertising the information required for path setting by the routing protocol, advertising that the own router has the ability to create the MPLS forwarding table;
14. The method according to claim 10, wherein information used for determining a label value at each hop in an MPLS path is added to advertisement information in a routing protocol for a router that has been confirmed to have the ability to create the MPLS forwarding table by the advertisement. Path setting method. When there are two or more paths between the start point and the end point of the MPLS path,
Create an MPLS forwarding table that records the correspondence between a plurality of MPLS labels corresponding to one destination address based on the other advertisement information,
14. The path setting method according to claim 13, wherein one of the plurality of MPLS labels is set to the active state and the other is set to the standby state and switched according to the occurrence of a failure. An MPLS network comprising the router according to claim 1.

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