JP2005072906A - Method and program for setting multicast alternate route, and label switching router - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set a partial alternate route in a multicast LSP constructed by a multicast MPLS switching system employing an RSVP-TE. <P>SOLUTION: An identifier for identifying a multicast LSP is attached to the multicast MPLS switching system employing the RSVP-TE, only a specific partial multicast LSP requiring a route change is reset, and for other subtrees, the setting of an alternate route is realized without performing a route change. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a multicast detour route setting method, a label switching router, and a multicast detour route setting program. In particular, in a one-to-many multicast LSP (label switching path) using a multicast MPLS switching method using RSVP-TE, The present invention relates to a multicast detour route setting method, a label switching router, and a multicast detour route setting program for setting an efficient detour route.

  A one-to-many multicast LSP using a multicast MPLS switching method using RSVP-TE is known (see, for example, Non-Patent Document 1). The multicast LSP is required to set an efficient detour route.

  In the multicast MPLS switching method using RSVP-TE, the incoming label switching router uses a message called a path message having information that lists the bandwidth to be reserved and the label switching router to be passed, and uses the incoming label switching router and the outgoing label. A label switch path called a label switching path (LSP) is set between the switching routers. The outgoing label switching router transmits a confirmation message to the incoming label switching router to indicate that the LSP has been successfully set. The LSP has an attribute such as a bandwidth to be reserved in the middle of the route, and is identified by a label switching router on the route using an identifier called LSPID (identifier for identifying the LSP).

  In addition, the multicast MPLS switching method using RSVP-TE has a function of SE style that shares a bandwidth required by each LSP when a plurality of LSPs pass through the same route.

  Here, the procedure of the detour route setting method when the conventional technology is used will be described.

Consider changing the route from the multicast LSP (a) as shown in FIG. 10 to the multicast LSP (d) using the conventional detour route setting method. Let L be the LSPID of (a) assigned by the incoming label switching router S. When the necessity of setting a detour route occurs and the route (d) is calculated, S sets (b) as an LSP with an LSPID of b using the SE style (state (c)). The multicast LSP with LSPID = a and the multicast LSP with LSPID = b share the bandwidth using the SE style. After confirming that part or all of (b) has been set, S switches the packet sent to (a) to (b), deletes (a), and bypasses the path. The setting is completed (FIG. 10 (d)).
IETF draft-yasukawa-mpls-rsvp-multicast-02.txt draft-raggarwa-mpls-rsvp-multicast-01.txt

  In the technique described above, in FIG. 10, the input label switching router S also performs the label switching even when performing the detour route setting for the output label switching router F (the detour target is a link connecting the label switching routers D and F). It is necessary to reset the entire multicast LSP including routers A, B, and C.

  In the conventional bypass route setting method using the SE style in the multicast MPLS switching method using RSVP-TE, switching is performed only by the incoming label switching router without performing any special procedure in the label switching router on the route. It is possible to prevent packet loss due to setting of a detour route and packet rescue operation due to retransmission between label switching routers. On the other hand, there is a problem that it is necessary to reset a route even for a route that is not a detour target, and that more time is required for setting a detour route as the number of outgoing label switching routers increases.

  The present invention has been made in view of the above points, and performs only partial reconfiguration without reconfiguring the entire multicast LSP while completing the advantages of the conventional method, and completes the detour route setting. An object of the present invention is to provide a multicast detour route setting method, a label switching router, and a multicast detour route setting program.

  FIG. 1 is a diagram for explaining the principle of the present invention.

The present invention relates to a detour route setting method using SE style, which is performed for a multicast LSP set by a multicast switching method using RSVP-TE and setting a one-to-many multicast LSP.
Set a multicast group identifier for limiting multicast LSPs that transfer packets addressed to the same multicast group (step 1),
In label switching router,
A process (step 2) of identifying a partial multicast LSP that includes a node or link to be bypassed and branches from the incoming label switching router among multicast LSPs of the same destination;
For the specified partial multicast LSPs (K is a natural number greater than or equal to 1), the SE style is used and the multicast group identifier having the same value as the original multicast LSP is included, and is included in the specified partial multicast LSP A step of setting K detour multicast LSPs including all incoming label switching routers and outgoing label switching routers and not including all detour targets for each partial multicast LSP (step 3);
After confirming the detour route setting, in the incoming label switching router,
The packet transfer addressed to the partial multicast LSP specified by the process of specifying the bypass target partial multicast LSP while maintaining the packet transfer addressed to the bypass untargeted partial multicast LSP not specified by the process of specifying the bypass target partial multicast LSP The process of starting forwarding the packet to be forwarded to the newly set detour multicast LSP identified by the multicast group identifier having the same value as the original multicast LSP (step 4);
After the transfer destination is switched, a process (step 5) of deleting the partial multicast LSP including the detour target identified by the process of identifying the detour target partial multicast LSP.

In the process of setting the detour multicast LSP for each partial multicast LSP,
For the K partial (K is a natural number of 1 or more) partial multicast LSPs that are specified by the process of specifying the bypass target partial multicast LSP, use the SE style and have the same value as the original multicast LSP S (where S is a natural number less than K) detours including all incoming label switching routers and outgoing label switching routers included in the specified partial multicast LSP, and not including all detour targets Including the process of configuring a multicast LSP,
In the process of starting forwarding to the detour multicast LSP,
A process of identifying a detour target partial multicast LSP while maintaining packet forwarding addressed to a detour untargeted partial multicast LSP that was not identified in the process of identifying a detour target partial multicast LSP in the incoming label switching router after confirming the detour path setting The packet forwarding addressed to the partial multicast LSP specified by the above is stopped, and at the same time, the newly set arbitrary bypass multicast LSP in which the packet to be transferred is specified by the multicast group identifier having the same value as the original multicast LSP Including the process of initiating the transfer,
After the transfer destination is switched, a process of specifying the partial multicast LSP including the bypass target specified by the process of specifying the bypass target partial multicast LSP is included.

Further, the present invention provides a process of identifying the detour target partial multicast LSP,
For each branching direction from the incoming label switching router, the multicast LSP is divided into partial multicast LSPs, and among the partial multicast LSPs, the partial multicast LSP including the node or link that is the detour target is specified as the detour target partial multicast LSP.

  FIG. 2 is a principle configuration diagram of the present invention.

The present invention is a label switching router 100 using an SE style, which is performed for a multicast LSP configured by a multicast switching method using RSVP-TE and setting a one-to-many multicast LSP,
LSP specifying means 120 for specifying a partial multicast LSP branching from an incoming label switching router that includes a detour target node or link among multicast LSPs of the same destination;
For the K partial multicast LSPs identified by the LSP identification unit 120 (K is a natural number of 1 or more), SE style is used, and packets addressed to the same multicast group having the same value as the original multicast LSP are sent. A multicast group identifier for limiting the multicast LSP to be transferred, including all incoming label switching routers and outgoing label switching routers included in the specified partial multicast LSP, and including a bypass multicast LSP that does not include all bypass targets Detour multicast LSP setting means 140 for setting K for each multicast LSP;
After confirming the detour route setting, the incoming label switching router maintains the packet forwarding addressed to the detour untargeted partial multicast LSP that has not been specified by the LSP specifying unit 120, and the packet addressed to the partial multicast LSP specified by the LSP specifying unit 120. At the same time as stopping the packet transfer, the packet to be transferred is forwarded to the above-described detour multicast LSP newly set by the detour multicast LSP setting means 140 specified by the multicast group identifier having the same value as the original multicast LSP Transfer control means 150 for starting
And LSP deletion means 170 for deleting the partial multicast LSP including the detour target specified by the LSP specification means 120 after switching the transfer destination.

The detour multicast LSP setting means 140 of the present invention
For the K partial multicast LSPs (K is a natural number greater than or equal to 1) including the detour targets specified by the LSP specifying unit 120, the SE style is used, and a multicast group identifier having the same value as the original multicast LSP is provided. Means for setting S (S is a natural number less than K) detour multicast LSPs that include all incoming label switching routers and outgoing label switching routers included in the specified partial multicast LSP and do not include all detour targets Including
The transfer control means 150
After confirming the detour route setting, in the incoming label switching router, the packet addressed to the partial multicast LSP specified by the LSP specifying means 120 while maintaining the packet transfer addressed to the detour untargeted partial multicast LSP not specified by the LSP specifying means 120 At the same time as stopping the transfer, the packet to be transferred is forwarded to an arbitrary detour multicast LSP newly set by the detour multicast LSP setting means 140, which is specified by the multicast group identifier having the same value as the original multicast LSP. Including means to start,
The LSP specifying means 120
After the transfer destination is switched, a means for specifying the partial multicast LSP including the detour target specified earlier is included.

The LSP specifying means 120 of the present invention
Means for dividing the multicast LSP into partial multicast LSPs for each branch direction from the incoming label switching router;
Among the divided partial multicast LSPs, there is included means for specifying a partial multicast LSP including a link or a node to be bypassed as a bypass target partial multicast LSP.

The present invention relates to a detour route setting program executed by a label switching router using an SE style, which is performed for a multicast LSP set by a multicast switching method using RSVP-TE to set a one-to-many multicast LSP. Because
An LSP specifying step for specifying a partial multicast LSP that includes a node or link to be detoured among the multicast LSPs of the same destination and branches from the incoming label switching router;
Uses the SE style for K partial multicast LSPs identified in the LSP identification step (K is a natural number of 1 or more), and transfers packets addressed to the same multicast group having the same value as the original multicast LSP. A partial multicast LSP is provided with a multicast group identifier for limiting the multicast LSP, includes all incoming label switching routers and outgoing label switching routers included in the specified partial multicast LSP, and does not include all bypass targets. A detour multicast LSP setting step of setting K pieces for each;
After confirming the detour route setting, the incoming label switching router maintains the packet transfer addressed to the non-circular partial multicast LSP not specified in the LSP specifying step, and transfers the packet addressed to the partial multicast LSP specified in the LSP specifying step. A transfer control step of starting forwarding to the newly set detour multicast LSP, which is specified by the multicast group identifier having the same value as that of the original multicast LSP,
After the transfer destination is switched, an LSP deletion step of deleting the partial multicast LSP including the detour target specified by the LSP specifying step is executed.

The detour multicast LSP setting step of the present invention includes
The SE style is used for K partial (K is a natural number of 1 or more) partial multicast LSPs including the detour targets specified in the LSP specifying step, and a multicast group identifier having the same value as the original multicast LSP is provided. A step of setting S (where S is a natural number less than K) detour multicast LSPs that include all incoming label switching routers and outgoing label switching routers included in the identified partial multicast LSP and do not include all detour targets. Including
The transfer control step is
After confirming the detour route setting, the incoming label switching router maintains the packet transfer addressed to the non-circular target partial multicast LSP that was not specified in the LSP specification step, and performs the packet transfer addressed to the partial multicast LSP specified in the LSP specification step. At the same time as stopping, including forwarding the packet to be forwarded to any newly configured detour multicast LSP identified by a multicast group identifier of the same value as the original multicast LSP;
The LSP identification step is
After the transfer destination is switched, a step of specifying the partial multicast LSP including the bypass target specified earlier is included.

The LSP specifying step of the present invention includes
Dividing the multicast LSP into partial multicast LSPs for each branch direction from the incoming label switching router;
Among the divided partial multicast LSPs, there is a step of identifying a partial multicast LSP including a node or link that is a detour target as a detour target partial multicast LSP.

  In the present invention, a multicast LSP having a different LSPID is recognized as the same multicast LSP by newly providing a multicast group identifier, so that a partial multicast LSP generated by partial route change is connected to an existing multicast LSP. It becomes possible to transmit packets of the same destination to the new multicast LSP and the old multicast LSP. By dividing the entire multicast LSP into partial multicast LSPs for each branch direction branching from the incoming label switching router, switching can be performed by the incoming label switching router, and packet loss due to switching can also be prevented.

  As a result, it is possible to partially set a detour path for a multicast LSP configured by the multicast MPLS switching method using RSVP-TE, and therefore it is possible to reduce the time for setting the detour path.

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

  First, terms used in the following description will be described.

LSPID: an identifier for identifying the LSP;
Multicast group identifier: An identifier for identifying a plurality of multicast LSPs. When the values are the same, they are handled as the same multicast LSP.

ST_tg: a detour target partial multicast LSP including a detour target link or node among the partial multicast LSPs divided for each branch direction from the incoming label switching router;
ST_ex: Multicast LSP of a detour-untargeted part that does not include a detour target link or node among the partial multicast LSPs divided from the outgoing label switching router for each branch direction;
ST_nw: Partial multicast LSP that has undergone a route change for ST_tg;
S: incoming label switching router;
ST_1, ST_2, ST_3: partial multicast LSP divided from S for each branch direction;
FIG. 3 shows the configuration of the label switching router in one embodiment of the present invention.

  The label switching router shown in the figure includes an LSP dividing unit 110, an LSP specifying unit 120, a detour circuit calculating unit 130, a detour multicast LSP setting unit 140, a transfer control unit 150, a packet transfer unit 160, and an LSP deletion unit 170. The

  When the label switching router functions as an incoming label switching router, the LSP dividing unit 110 divides the multicast LSP into partial multicast LSPs for each branch direction.

  The LSP specifying unit 120 specifies a detour target partial multicast LSP including a detour target from the divided partial multicast LSP.

  The bypass circuit calculation unit 130 calculates the specified bypass route using a route calculation algorithm.

  The bypass multicast LSP setting unit 140 uses the SE style for the specified partial multicast LSP, has a multicast group identifier having the same value as the original multicast LSP, and includes all of the specified partial multicast LSPs A detour multicast LSP that includes all the incoming label switching routers and outgoing label switching routers and does not include all detour targets is set for each partial multicast LSP.

  After confirming the detour route setting, the transfer control unit 150 instructs the packet transfer unit 160 to maintain the packet transfer addressed to the detour untargeted partial multicast LSP that has not been specified by the LSP specifying unit 120 in the incoming label switching router. The packet forwarding unit 160 is instructed to transfer a packet addressed to the partial multicast LSP specified by the LSP specifying unit 120, and the packet to be transferred is specified by the multicast group identifier having the same value as the original multicast LSP. The packet transfer unit 160 is instructed to transfer to the bypass multicast LSP newly set by the bypass multicast LSP setting unit 140. Further, after switching the transfer destination, the LSP deletion unit 170 is instructed to delete the partial multicast LSP including the detour target specified by the LSP specifying unit 120.

  The packet transfer unit 160 transfers the packet to the detour multicast LSP specified by the LSP specifying unit 120 according to an instruction from the transfer control unit 150.

The LSP deletion unit 170 deletes the partial multicast LSP including the detour target specified by the LSP specification unit 120 according to the instruction of the transfer control unit 150. FIG. 4 explains the outline of the operation according to the embodiment of the present invention. FIG. 5 is a flowchart of the operation in one embodiment of the present invention.

  A new multicast group identifier different from the LSPID is assigned to the multicast LSP (FIG. 4A). The incoming label switching router divides the entire multicast LSP for each branching direction branching from the incoming label switching router (step 101), and the divided partial multicast LSP includes a bypass target (link or node). Dividing into partial multicast LSP (ST_tg) and detour-untargeted partial multicast LSP (ST_ex) not including a detour target (FIG. 4B) (step 102), only ST_tg is the same multicast group with different LSPID in SE style The multicast LSP that bypasses the detour target with the identifier is reset (FIG. 4C) (step 103).

  The label switching router switches between ST_tg having a different LSPID and the newly reconfigured partial multicast LSP (ST_nw) on condition that the branch direction and the multicast group identifier are the same, and transmits to ST_tg. The transfer of the received packet to ST_nw is started (FIG. 4D). After switching is completed, ST_tg is deleted (step 105), ST_ex and ST_nw having different LSPIDs and the same multicast group identifier are recognized as the same multicast LSP, and the same destination packet is continuously transmitted (step 104). .

  Embodiments of the present invention will be described below with reference to the drawings.

  6 and 7 are diagrams for explaining the first embodiment of the present invention.

  FIG. 6A shows a multicast LSP configured by a multicast MPLS switching method using RSVP-TE, with multicast group identifier = 1 and LSPID = 1. Hereinafter, an example in which the link between the multicast LSP label switching routers S and D and the bypass target node I are bypassed and a bypass path is set for each partial multicast LSP will be described.

  (1) In the incoming label switching router S, the LSP dividing unit 110 divides the multicast LSP into partial multicast LSPs for each branch direction of S. Since S is branched into three paths, it can be divided into three partial multicast LSPs, and the partial multicast LSPs obtained by the division are denoted by ST_1, ST_2, ST_3 (FIG. 6 (b)). To do.

  (2) Next, in the incoming label switching router S, the LSP identification unit 120 identifies the detour target partial multicast LSP including the detour target as ST_2 and ST_3.

  (3) The bypass route calculation unit 130 calculates the bypass route using a route calculation algorithm such as IS-IS or OSPF. The calculation results are ST_4 and ST_5 (FIG. 7C).

  (4) The incoming label switching router S sets ST_4 and ST_5 as multicast group identifier = 1 and LSPID = 2 in the detour multicast LSP setting unit 140.

  (5) After receiving a confirmation message from router E, F, H, J, K indicating that the multicast LSP after detouring has been successfully set, incoming label switching router S uses LSPID in transfer controller 150. Are different and have the same multicast group identifier, switch between ST_2 and ST_4, ST_3 and ST_5, and send packets to be sent to ST_2 and ST_3 to ST_4 and ST_5. Also, ST_1, ST_4 and ST_5 are the same The packet transfer unit 160 is instructed to start transmission of a packet as a multicast LSP, and the packet transfer unit 160 transmits the packet.

  (6) The incoming label switching router S cancels the setting of the partial multicast LSP for ST_2 and ST_3 in the LSP deletion unit 170.

  8 and 9 are diagrams for explaining a second embodiment of the present invention. FIG. 8A shows a multicast LSP configured by a multicast MPLS switching method using RSVP-TE, with multicast group identifier = 1 and LSPID = 1. Hereinafter, an example in which the link between the label switching routers S and D in the multicast LSP and the detour target node I are detoured and a partial multicast LSP after detour that is smaller than the original partial multicast LSP is set will be described.

  (1) In the incoming label switching router S, the LSP dividing unit 110 divides the multicast LSP into partial multicast LSPs for each branching direction of the S. Since S is branched into three paths, it can be divided into three partial multicast LSPs, and the partial multicast LSPs obtained by the division are defined as ST_1, ST_2, ST_3 (FIG. 8B). .

  (2) In the incoming label switching router S, the LSP identification unit 120 identifies the detour target partial multicast LSP including the detour target as ST_2 and ST_3.

  (3) The bypass route calculation unit 130 calculates the bypass route using a route calculation algorithm such as IS-IS or OSPF. The result is ST_4 (FIG. 9C).

  (4) The incoming label switching router S sets ST_4 as multicast group identifier = 1 and LSPID = 2 in the bypass multicast LSP setting unit 140.

  (5) After receiving a confirmation message from the nodes E, F, H, J, and K indicating that the multicast LSP after detouring can be normally set, the incoming label switching router S uses the LSPID in the transfer control unit 150. And ST_1, ST_4, ST_5, instructing the packet transfer unit 160 to switch ST_2, ST_3 and ST_4, which have the same multicast group identifier in the same branch direction, and to transmit the packet to be sent to ST_2 and ST_3 to ST_5. Are transmitted to the packet transfer unit 160 as the same multicast LSP. The packet transfer unit 160 transfers the packet according to an instruction from the transfer control unit 150.

  (6) The incoming label switching router S cancels the setting of the partial multicast LSP for ST_2 and ST_3 in the LSP deletion unit 170.

  Further, the operation of the label switching router can be constructed as a program and installed in a computer used as a label switching router, or distributed via a network.

  It is also possible to store the constructed program in a portable storage medium such as a hard disk, a flexible disk, a CD-ROM, etc. connected to a computer used as a label switching router and install it on the computer at the time of execution. is there.

  The present invention is not limited to the above-described embodiments and examples, and various modifications and applications are possible within the scope of the claims.

  The present invention can be used for setting a detour route for a multicast LSP configured by a multicast MPLS switching method using RSVP-TE.

It is a figure for demonstrating the principle of this invention. It is a principle block diagram of this invention. It is a block diagram of the label switching router in one embodiment of this invention. It is a figure for demonstrating the outline | summary of the operation | movement in one embodiment of this invention. It is a flowchart of the operation | movement in one embodiment of this invention. It is FIG. (1) for demonstrating Example 1 of this invention. It is FIG. (2) for demonstrating Example 1 of this invention. It is FIG. (1) for demonstrating Example 2 of this invention. It is FIG. (2) for demonstrating Example 2 of this invention. It is a figure for demonstrating the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Label switching router 110 LSP division | segmentation part 120 LSP identification means, LSP identification part 130 Detour route calculation part 140 Detour multicast LSP setting means, Detour multicast LSP setting part 150 Transfer control means, Transfer control part 160 Packet transfer part 170 LSP deletion means, LSP deletion part

Claims (9)

RSVP-TE (Resource
Uses reSarVation Protocol-Traffic Engineering) to share multiple bandwidth reservations made for multicast LSPs set by the multicast switching method that sets up one-to-many multicast label switching paths (hereinafter referred to as LSPs) In the detour route setting method using the reservation form (hereinafter referred to as SE style)
Providing a multicast group identifier for limiting multicast LSPs that forward packets addressed to the same multicast group;
In label switching router,
A process of identifying a partial multicast LSP that includes a detour target node or link and branches from an incoming label switching router among multicast LSPs of the same destination;
For the specified partial multicast LSPs (K is a natural number greater than or equal to 1), the SE style is used and the multicast group identifier having the same value as the original multicast LSP is included, and is included in the specified partial multicast LSP A process of setting K detour multicast LSPs that include all incoming label switching routers and outgoing label switching routers and do not include all detour targets for each partial multicast LSP;
After confirming the detour route setting, in the incoming label switching router,
The packet addressed to the partial multicast LSP specified by the process of specifying the bypass target partial multicast LSP while maintaining the packet transfer addressed to the bypass untargeted partial multicast LSP not specified by the process of specifying the bypass target partial multicast LSP A process of stopping forwarding and simultaneously starting forwarding the packet to be forwarded to the newly set detour multicast LSP identified by the multicast group identifier having the same value as the original multicast LSP;
A detour route setting method comprising: a step of deleting a partial multicast LSP including a detour target identified by a process of identifying the detour target partial multicast LSP after switching of a transfer destination. In the process of setting the bypass multicast LSP for each partial multicast LSP,
For the K partial multicast LSPs (K is a natural number greater than or equal to 1) that includes the detour targets, which are identified by the process of identifying the detour target partial multicast LSP, S pieces (S is a natural number less than K) having multicast group identifiers of the same value, including all incoming label switching routers and outgoing label switching routers included in the specified partial multicast LSP, and not including all detour targets Including the process of setting the detour multicast LSP of
In the process of starting forwarding to the bypass multicast LSP,
After confirming the detour route setting, the incoming label switching router maintains the packet forwarding addressed to the detour untargeted partial multicast LSP that has not been specified by the process of specifying the detour target partial multicast LSP, and The packet forwarding addressed to the partial multicast LSP specified by the specifying process is stopped, and at the same time, the packet to be transferred is specified by a multicast group identifier having the same value as that of the original multicast LSP. Including the process of initiating forwarding to the detour multicast LSP,
The detour route setting method according to claim 1, further comprising a step of specifying as a partial multicast LSP including a detour target specified by the step of identifying the detour target partial multicast LSP after switching of a transfer destination. In the process of identifying the detour target partial multicast LSP,
The multicast LSP is divided into partial multicast LSPs for each branching direction from the incoming label switching router, and the partial multicast LSP including the link or the partial multicast LSP including the link is specified as the bypass target partial multicast LSP among the partial multicast LSPs. The detour route setting method according to claim 1 or 2. RSVP-TE (Resource
Uses reSarVation Protocol-Traffic Engineering) to share multiple bandwidth reservations made for multicast LSPs set by the multicast switching method that sets up one-to-many multicast label switching paths (hereinafter referred to as LSPs) A label switching router using a reservation form (hereinafter referred to as SE style),
LSP specifying means for specifying a partial multicast LSP that includes a node or link that is a detour among the multicast LSPs of the same destination and branches from the incoming label switching router;
Packets addressed to the same multicast group having the same value as the original multicast LSP using the SE style for K partial multicast LSPs specified by the LSP specifying means (K is a natural number of 1 or more) A detour multicast LSP having a multicast group identifier for limiting the multicast LSP that forwards, including all incoming label switching routers and outgoing label switching routers included in the specified partial multicast LSP, and not including all detour targets, Detour multicast LSP setting means for setting K for each partial multicast LSP;
After confirming the detour route setting, the incoming label switching router maintains the packet forwarding addressed to the detour untargeted partial multicast LSP that has not been specified by the LSP specifying unit, and the packet addressed to the partial multicast LSP specified by the LSP specifying unit. At the same time as stopping the packet transfer, the packet to be transferred is forwarded to the bypass multicast LSP newly set by the bypass multicast LSP setting means specified by the multicast group identifier having the same value as the original multicast LSP. Transfer control means to start;
LSP deletion means for deleting a partial multicast LSP including a detour target specified by the LSP specifying means after switching of the transfer destination;
A label switching router characterized by comprising: The detour multicast LSP setting means includes:
For the K partial multicast LSPs (K is a natural number greater than or equal to 1) including the detour targets specified by the LSP specifying means, using the SE style, a multicast group identifier having the same value as the original multicast LSP is set. And S (where S is a natural number less than K) detour multicast LSPs including all incoming label switching routers and outgoing label switching routers included in the specified partial multicast LSP and not including all detour targets. Including means,
The transfer control means includes
After confirming the detour route setting, in the incoming label switching router, while maintaining the packet transfer addressed to the detour untargeted partial multicast LSP that has not been specified by the LSP specifying means, the packet to the partial multicast LSP specified by the LSP specifying means is maintained. At the same time as stopping the packet transfer, the packet to be transferred is forwarded to the bypass multicast LSP newly set by the bypass multicast LSP setting means specified by the multicast group identifier having the same value as the original multicast LSP. Including means to start,
The LSP specifying means is:
5. The label switching router according to claim 4, further comprising means for specifying the partial multicast LSP including the detour target specified earlier after switching the transfer destination. The LSP specifying means is:
Means for dividing the multicast LSP into partial multicast LSPs for each branch direction from the incoming label switching router;
The label switching router according to claim 4 or 5, further comprising means for identifying a partial multicast LSP including a link or a node that is a detour target among the divided partial multicast LSPs as a detour target partial multicast LSP. RSVP-TE (Resource
Uses reSarVation Protocol-Traffic Engineering) to share multiple bandwidth reservations made for multicast LSPs set by the multicast switching method that sets up one-to-many multicast label switching paths (hereinafter referred to as LSPs) A detour route setting program executed by a label switching router using a reservation form (hereinafter referred to as SE style),
An LSP specifying step for specifying a partial multicast LSP that includes a node or link to be detoured among the multicast LSPs of the same destination and branches from the incoming label switching router;
For the K partial multicast LSPs identified in the LSP identification step (K is a natural number equal to or greater than 1), the packets using the SE style and having the same value as the original multicast LSP and addressed to the same multicast group A detour multicast LSP having a multicast group identifier for limiting the multicast LSP that forwards, including all incoming label switching routers and outgoing label switching routers included in the specified partial multicast LSP, and not including all detour targets, A detour multicast LSP setting step of setting K for each partial multicast LSP;
After confirming the detour path setting, the incoming label switching router maintains the packet forwarding addressed to the detour untargeted partial multicast LSP that has not been specified in the LSP specifying step, while addressing the partial multicast LSP specified in the LSP specifying step. At the same time as stopping the packet transfer, the packet to be transferred is forwarded to the bypass multicast LSP newly set in the bypass multicast LSP setting step specified by the multicast group identifier having the same value as the original multicast LSP. A transfer control step to start; and
An LSP deletion step of deleting a partial multicast LSP including the detour target specified by the LSP specifying step after switching of the transfer destination;
A detour route setting program characterized by executing The bypass multicast LSP setting step includes:
Using the SE style, a multicast group identifier having the same value as that of the original multicast LSP is used for K partial (K is a natural number of 1 or more) partial multicast LSPs including the detour targets specified in the LSP specifying step. And S (where S is a natural number less than K) detour multicast LSPs including all incoming label switching routers and outgoing label switching routers included in the specified partial multicast LSP and not including all detour targets. Including steps,
The transfer control step includes:
After confirming the detour route setting, the incoming label switching router maintains the packet forwarding addressed to the detour untargeted partial multicast LSP that has not been specified in the LSP specifying step, and is directed to the partial multicast LSP specified in the LSP specifying step. At the same time as stopping the packet transfer, the packet to be transferred is forwarded to the bypass multicast LSP newly set in the bypass multicast LSP setting step specified by the multicast group identifier having the same value as the original multicast LSP. Including steps to start,
The LSP specifying step includes:
The detour route setting program according to claim 7, further comprising a step of identifying the partial multicast LSP including the detour target identified earlier after switching the transfer destination. The LSP specifying step includes:
Dividing the multicast LSP into partial multicast LSPs for each branch direction from the incoming label switching router;
The detour route setting program according to claim 7 or 8, further comprising a step of identifying a partial multicast LSP including a link or a node that is a detour target among the divided partial multicast LSPs as a detour target partial multicast LSP.

Images