JP2007074311A - Bypass lsp setting method, multicast mpls forwarding device, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bypass LSP setting technique which is capable of quickly switching a protection object LSP when a node gets faulty, while suppressing the increase in number of bypass LSPs. <P>SOLUTION: A preceding node placed immediately before a protection object node determines a label peculiar to the protection object LSP and reports the label downstream, and merge nodes store the label peculiar to the protection object LSP. The preceding node sets a multicast LSP having all detected merge nodes as leaves, as a bypass LSP. The merge nodes associate an incoming label of the bypass LSP, the label peculiar to the protection object LSP, and an outgoing label of the protection object LSP with one another. When a fault occurs, the preceding node stacks the label peculiar to the protection object LSP as a second label and forwards packets to the bypass LSP, and the merge nodes use a top label of received packets and the second label to specify the outgoing label of the protection object LSP and forwards the packets below the protection object LSP. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multicast MPLS node failure high-speed detour technique, and more particularly to a technique for setting a detour path for switching when a node failure occurs in a protection target LSP in a communication network configured by a multicast MPLS transmission apparatus. About.

  In the MPLS communication network, when a failure occurs in a certain node (this node is called a protection target node) through which the protection target LSP passes, a unicast bypass LSP is set in advance in order to bypass the protection target node at high speed. The method of setting is taken. Furthermore, in order to reduce the number of bypass LSPs, there is a method of using one bypass LSP for a plurality of protection target LSPs.

  A conventional method for setting a high-speed detour LSP at the time of a node failure will be described with reference to FIGS. 1 and 2.

  In the MPLS communication network of FIG. 1A, the node Z is a protection target node. Further, assuming that the LSP passing through A, Z, and D is the protection target LSP1, the node A that is the previous node of Z becomes the previous node, and the node D that is the next node of Z becomes the merge node.

  In the process of setting the protection target LSP1 by exchanging a path and reserve message based on RSVP-TE (Resource ReServation Protocol-Traffic Engineering) between the nodes, the node A is that it is a previous node. , Recognize that the merge node is D. Further, the node A simultaneously recognizes that the MPLS label from Z to D is “19”.

  Next, the node A sets a unicast bypass LSP (referred to as a bypass LSP3) to the merge node without going through the protection target node Z.

  When there is another protection target LSP as shown in FIG. 1B, a bypass LSP is similarly set. In the example of FIG. 1B, detour LSPs 4 and 5 are set for the merge nodes C and E for the protection target LSP 2 that is a multicast LSP. At this time, for the merge node D, one bypass LSP (detour LSP3) is shared between a plurality of protection target LSPs (protection target LSPs 1 and 2) having the same merge node.

  FIG. 2 is a diagram for explaining label switching when a failure occurs in the protection target node Z in the case of FIG. 1B and data transfer is switched to the detour LSP.

  In the data of the protection target LSP1, in A, the label 19 from Z to D is stacked as a second label and transferred to the detour LSP3. In the bypass LSP 3, only the top label is swapped at the relay nodes B and C, and the data is transferred to the node D. In the node D, the top label is popped, and the swap similar to that of the protection target LSP1 is performed for the second level (that is, the label 19 is changed to the label 20), and the data is transferred.

  Similarly, for the data of the protection target LSP2, for D, a label 28 from Z to D is stacked as a second label and transferred to the detour LSP3. In the detour LSP 3, only the top label is swapped at the relay node and transferred to the node D. Node D pops the top label, performs swap similar to protection LSP2 for the second label (that is, changes label 28 to label 31), and transfers the data.

  For C, a label 27 from Z to C is stacked as a second label and transferred to the detour LSP 4. In the detour LSP 4, only the top label is swapped at the relay node and transferred to the node C. Node C pops the top label, performs swap similar to that of protection target LSP2 for the second label (that is, changes label 27 to label 30), and transfers the data. Further, for E, a label 29 from Z to E is stacked as a second label and transferred to the detour LSP 5. In the detour LSP 5, only the top label is swapped at the relay node and transferred to the node E. In node E, the top label is popped, swap is performed on the second label in the same manner as the protection target LSP2 (that is, label 29 is changed to label 32), and data is transferred.

There is Non-Patent Document 1 as a reference for the detour LSP. Further, the path message and the reserve message in this specification are defined in Non-Patent Document 2. Further, Patent Documents 1 to 3 are examples of prior art documents related to multicast MPLS.
IETF RFC4090 “Fast Reroute Extensions to RSVP-TE for LSP Tunnels” http://www.ietf.org/rfc/rfc4090.txt, sections 6.4, 6.5, and 7 “Extensions to RSVP-TE for Point to Multipoint TE LSPs” http://www.ietf.org/internet-drafts/draft-ietf-mpls-rsvp-te-p2mp-02.txt, Chapters 5-6 (10 Page to page 19) Japanese Patent Laid-Open No. 2004-356876 JP 2005-72906 A JP 2005-167482 A

  By the conventional technology described above, it is possible to set a bypass LSP that can switch the protection target LSP at a high speed in the event of a node failure. In addition, a plurality of protection target LSP data can be sorted at the merge node by the stacked secondary labels. As a result, a plurality of protection target LSPs can be bypassed by a single bypass LSP, and the number of LSPs can be reduced.

  However, in the bypass LSP by the unicast LSP in the existing technology, as many bypass LSPs as the number of merge nodes are required as shown in FIG. 1B, and with the increase in the number of merge nodes due to the increase in the number of protection target LSPs Thus, there is a problem that the number of bypass LSPs increases and an excessive load occurs at each node. Further, in the existing technology, when protecting the multicast LSP, there is a problem that a branch occurs in the previous node at the time of failure, and transfer efficiency is lowered.

  It is an object of the present invention to provide a technique for setting a bypass LSP that can switch a protection target LSP at a high speed in the event of a node failure while suppressing the number of bypass LSPs against an increase in the number of protection target LSPs. .

The above problem is a detour LSP (Label Switched Path) setting method for dealing with a node failure in an MPLS communication network configured by a multicast transmission device,
The previous node, which is the previous node of the protection target node on the path of the protection target LSP, determines a label specific to the protection target LSP and notifies it downstream; The next node, the merge node, stores the label unique to the protection target LSP assigned by the previous node and the identifier of the protection target LSP, and after the setting of the protection target LSP is completed, the previous node detects the merge node. A step of performing a process for setting a multicast LSP whose leaves are all merge nodes detected by the previous node as a bypass LSP in a route not passing through the protection target node, and after completing the setting of the bypass LSP, Based on the identifier of the protection target LSP, the merge node determines the entry label of the detour LSP, the label unique to the protection target LSP, and the protection pair. And a step of associating the outgoing label of the LSP, and at the time of failure, the previous node stacks a label unique to the LSP to be protected as a second label, forwards the packet to the detour LSP, and the merge node receives This can be solved by a detour LSP setting method characterized in that the outgoing label of the protection target LSP is specified using the top label and the second label of the packet and the packet is transferred downstream of the protection target LSP.

  When a merge node is added, a multicast LSP leaf is added instead of newly setting a bypass LSP.

  In addition, the above-described problem is a detour LSP setting method for dealing with a node failure in an MPLS communication network configured by a multicast transmission apparatus, and is protected on the path of the protection target LSP after the setting of the protection target LSP is completed. The previous node that is the node immediately before the target node detects a merge node that is the next node of the protection target node on the path of the protection target LSP, and the previous node uses the detected merge node as a leaf. A step of determining a multicast LSP as a bypass LSP for each protection target LSP on a route that does not pass through the protection target node, and sending a path message including the identifier of the protection target LSP to the route of the bypass LSP; Receiving a path message for setting and storing the identifier of the LSP to be protected; After the SP setting is completed, the merge node has a step of associating the incoming label of the detour LSP with the outgoing label of the protection target LSP based on the identifier of the protection target LSP. The packet of the protection target LSP is transferred to the detour LSP corresponding to the protection target LSP, the merge node specifies the outgoing label of the protection target LSP using the top label of the received packet, and the packet is designated as the protection target LSP. This problem can also be solved by a detour LSP setting method characterized by transferring to the downstream side.

  The present invention can also be realized as a multicast MPLS transfer device that functions as a previous node and a merge node in the detour LSP setting method, and a program for each multicast MPLS transfer device.

  According to the present invention, it is possible to solve the conventional problem that the number of bypass LSPs increases as the number of merge nodes increases by using multicast LSPs with all merge nodes as leaves as bypass LSPs.

  Further, even when a multicast LSP is used as a bypass LSP, a plurality of protection target LSPs can be shared and transferred by one bypass LSP by issuing a label from the previous node and an association table in the merge node. Even if the target LSP increases, the number of bypass LSPs can be suppressed.

  Therefore, according to the present invention, it is possible to realize a bypass LSP setting that can switch the protection target LSP at a high speed in the event of a node failure while suppressing the number of bypass LSPs.

  The best mode for carrying out the present invention will be described with reference to the drawings.

<First Embodiment>
First, a first embodiment of the present invention will be described.

(Overview of node operation)
First, an outline of the node in the present embodiment will be described. A device that constitutes a node is a transmission device such as a router (also referred to as a multicast MPLS transfer device), and functions as a computer having a CPU and storage means such as a memory and a hard disk, and a communication function such as a network interface. I have. The processing content described in this embodiment can be realized by a program installed in the transmission apparatus.

  With reference to FIGS. 3 to 5, focusing on one node in the present embodiment, an operation outline of how the node operates according to the type of message to be received will be described. Note that the path message and the reserve message in the present embodiment are RSVP-TE messages compatible with multicast MPLS.

  FIG. 3 is a flowchart showing the operation of the node when the node receives the pass message.

  When receiving the path message, the node determines whether or not the path message is for setting the protection target LSP (step 1). If it is for the protection target LSP, the path information in the path message is referenced to determine whether it is a previous node or a merge node (step 2). If it is not for the protection target LSP, an LSP setting process (step 5) is performed.

  If it is determined in step 2 that it is the previous node, a label unique to the protection target LSP is determined and stored in the storage means (step 3). When it is determined that the node itself is a merge node, a label specific to the protection target LSP that is given in the previous node and included in the path message is acquired and associated with the protection target LSP identifier included in the path message. Store in the storage means (step 4). Thereafter, the process proceeds to the LSP setting process (step 5).

  Next, the operation of a node when a reserve message is received will be described with reference to FIG.

  First, it is determined whether the received reserve message is for the protection target LSP or the detour LSP (step 11). If it is for the protection target LSP, based on the content of the reserve message, it is determined whether or not it is the previous node (step 12). If it is the previous node, the merge node is detected from the contents of the reserve message and stored in the storage means (step 13). If it is not the previous node in step 12, the process proceeds to LSP setting processing (step 19). When a merge node is detected in step 13, a process for setting a multicast LSP having a merge node as a leaf as a bypass LSP is performed on a route that does not pass through the protection target node (step 14).

  If it is determined in step 11 that the reserve message is for the bypass LSP, it is determined whether it is a previous node or a merge node (step 15). If it is the previous node, a failure label table to be referred to at the time of failure is created and stored in the storage means (step 16), and merge node management processing (number management, etc.) is performed (step 17). If it is determined in step 15 that the node is a merge node, a detour label table is created and stored in the storage means (step 18). Thereafter, the process proceeds to the LSP setting process (step 19).

  Next, an operation when a labeled packet is received after a failure has occurred in the protection target node will be described with reference to FIG.

  First, it is determined whether or not the packet itself is the previous node and the received labeled packet is a packet of the protection target LSP (step 21). When the packet itself is a previous node and the received labeled packet is a packet of the protection target LSP, a label unique to the protection target LSP stored in the storage means is stacked as a second label (step 22). The packet is transferred with reference to the failure label table (step 23).

  In step 21, if the received packet with the label is a packet of the protection target LSP, except for the case where the received packet with the label is a packet of the protection target LSP, the received packet with the label is the protection node LSP. It is determined whether it is a packet (step 24). If so, a second label is determined (step 24), and the packet is transferred with reference to the detour label table. In step 24, when the packet is a merge node and the received labeled packet is a packet of the protection target LSP, the transfer is performed with reference to the normal transfer label table.

(System operation details)
Next, with reference to FIG. 6 and FIG. 7, an operation example in the system of the present embodiment will be described.

  Here, the setting of the detour LSP for the protection target LSP1 and the protection target LSP2 shown in FIG. 1B will be described.

  First, in the process of setting the protection target LSP1, when the node A which is the previous node receives the path message of the protection target LSP1, the node A recognizes from the path message that the LSP1 is the protection target LSP, and the protection target LSP1 The label a associated with LSP1 is determined and stored in the storage means. The path message includes the label a and transfers it downstream.

  The node D that has received the path message including the label a recognizes that its own node is a merge node from the path information of the path message, and stores the label a in association with the identifier of the protection target LSP1 included in the path message. Store in the means. Further, when receiving the reserve message for setting the protection target LSP1, the node D creates a transfer label table (first line in FIG. 7 (f)) referred to in the normal state, and stores it in the storage means. .

  Thereafter, a reserve message corresponding to the protection target LSP1 setting path message is sent to the node A, and the node A detects the merge node D by referring to the path information of the reserve message. Then, the node A that has detected the merge node D sets the multicast LSP up to the node D as the bypass LSP3. That is, the detour route is determined and a path message including the identifier of the protection target LSP1 is transmitted. In addition, the node A creates a transfer label table (first line in FIG. 7A) that is referred to in the normal state, and stores it in the storage means.

  In the process of setting the bypass LSP3, the node D that has received the reserve message of the bypass LSP3 from the downstream determines the label 12 that is the transfer label of the bypass LSP3, and the label 12, the label a, and the outgoing label of the protection target LSP1 20 (determined from the identifier of the protection target LSP1) is created to create a detour label table (first line in FIG. 7 (g)) and store it in the storage means. Further, a transfer label table shown in the bottom row of FIG. Then, the node D transfers the reserve message to the upstream of the detour LSP3, and the nodes C and B that have received the reserve message are for transfer for the second stage of FIG. 7D and the detour LSP3 of FIG. Create a label table.

  The node A that has received the reserve message for the detour LSP 3 creates the failure label tables on the first and second lines in FIG. 7B and stores them in the storage means.

  The same operation is performed for the protection target LSP2, and the label b is assigned in the node A, and the multicast LSP added with the merge nodes C and E as leaves is reset. That is, the label b and the label 11 are associated at the node C, the label b and the label 12 are associated at the node D, and the label b and the label 13 are associated at the node E. Thereby, the tables shown in FIGS. 7A to 7I are created.

  Next, the operation when a failure occurs in the node Z that is the protection target node will be described with reference to FIG.

  When a failure occurs in the node Z, the node A that detects the failure switches the reference destination from the normal transfer label table shown in FIG. 7A to the failure label table shown in FIG. 7B.

  The node A that has received the packet of the protection target LSP1 to which the label 17 is assigned searches the FIG. 7B, and swaps the label 17 to the label a. Thereafter, the packet is output to the virtual interface (Lo) to the own node. Further, FIG. 7B is searched using the label a, and the label 10 is assigned and transferred to the node B.

  The node B swaps the label 10 to the label 11 and transfers it to the node C using the transfer label table shown in FIG. The node C refers to the transfer label table shown in FIG. 7 (d), copies the received packet, swaps the label 11 to the label 12, and transfers it to the node D, and the label 11 for the other packet. The second label search operation is performed for. In the second label search, the detour table in FIG. 7E is searched using the label 11 and the label a. However, since the second label in the table is the label b, the hit is not made in the detour table, and the packet is discarded. Is done.

  The node D that has received the packet with the label 12 refers to the transfer label table in FIG. 7 (f), copies the packet, swaps the label 12 to the label 13, and transfers to the node E. The second label search is performed on the label 12. In the second label search, the detour label table of FIG. 7G is searched using the label 12 and the label a. Since the first row of the table is hit, the label 12 is deleted, and the label a is set to the label 20 and transferred to the downstream node of the protection target LSP1.

  The node E that has received the packet with the label 13 refers to the transfer label table shown in FIG. 7 (h) and uses the label 13 and the label a for the detour label table shown in FIG. 7 (i). Perform a second label search. Since the second label in the table is label b, the packet is discarded.

  Next, a case where a packet of the protection target LSP2 with the label 25 is received will be described.

  The node A receiving the packet with the label 25 searches FIG. 7B and swaps the label 25 with the label b. Thereafter, the packet is output to the virtual interface (Lo) to the own node. Further, FIG. 7B is searched using the label b, and the label 10 is assigned and transferred to the node B.

  The node B swaps the label 10 to the label 11 and transfers it to the node C using the transfer label table shown in FIG. The node C refers to the transfer label table shown in FIG. 7 (d), copies the received packet, swaps the label 11 to the label 12, and transfers it to the node D, and the second label for the other packet. Perform the search operation. In the second label search, the detour table in FIG. 7E is searched using the label 11 and the label b, the label 11 is deleted, the label b is swapped with the label 30, and transferred downstream of the protection target LSP2. To do.

  The node D that has received the packet with the label 12 refers to the transfer label table in FIG. 7 (f), copies the packet, swaps the label 12 to the label 13, and transfers to the node E. The second label search is performed on the label 12. In the second label search, the label 12 and the label b are used to search the detour label table in FIG. 7G, the label 12 is deleted, and the operation of swapping the label b to the label 31 is performed. Transfer downstream of LSP2.

  The node E that has received the packet with the label 13 refers to the transfer label table shown in FIG. 7 (h) and uses the label 13 and the label b with respect to the detour label table shown in FIG. 7 (i). A second label search is performed, label 13 is deleted, label b is swapped with label 32, and the packet is transferred downstream of protection target LSP2.

(About device configuration)
Next, a functional configuration of the transmission apparatus configuring the node in the present embodiment will be described. FIG. 8 is a block diagram illustrating a functional configuration of the transmission apparatus according to the present embodiment. Each function unit illustrated in FIG. 8 is realized by causing a transmission device to execute a program.

  As shown in FIG. 8, the transmission apparatus 10 according to the present embodiment includes a packet receiving unit 11, a packet analyzing unit 12, a bypass LSP setting control unit 13, a packet transfer control unit 14, an LSP setting unit 15, a packet transfer unit 16, A storage unit 17 is included.

  The packet receiver 11 receives a packet from the network and passes it to the packet analyzer 12. The packet analysis unit 12 determines whether the received packet is a path message, a reserve message, or a labeled packet. The detour LSP setting control unit 13 receives a path message or a reserve message and performs detour LSP setting control. The packet transfer control unit 14 receives a labeled packet and performs packet transfer control based on the label. The LSP setting unit 15 performs processing for LSP setting based on a path message and a reserve message, and creates a transfer label table.

  The packet transfer unit 16 transfers the labeled packet to the output interface (IF) described in each table. As shown in FIG. 7, the output interface includes a virtual interface that is designated as an output destination when the packet is reprocessed by the own node. The storage unit 17 includes a detour label table storage unit, a second label primary storage unit, a merge node storage unit, a failure label table storage unit, and a transfer label table storage unit.

  Next, the configurations of the bypass LSP setting control unit 13 and the packet transfer control unit 14 will be described in more detail with reference to FIGS. 9, 10, and 11.

  FIG. 9 is a diagram showing extracted functional units that operate when the detour LSP setting control unit 13 receives a path message.

  In FIG. 9, the protection target LSP determination unit 130 determines whether the received path message is for the protection target LSP or not, and moves the process to the previous node / merging node determination unit 131 if the received path message is for the protection target LSP. . If it is not for the protection target LSP, the process proceeds to the LSP setting unit 15. Based on the route information described in the path message, the previous node / merge node determination unit 131 determines that the current node is located immediately before the protection target node, and is determined as a merge node if located next to the node to be protected. . If it is the previous node, the processing is performed by the protection target LSP label management unit 132, and if it is a merge node, the processing by the second label acquisition unit 133 is performed.

  The protection target LSP label management unit 132 selects a label that is not used as a transfer label, and stores it in the second label storage unit as a label unique to the protection target LSP related to the received path message. Thereafter, processing in the LSP setting unit 15 is performed.

  The second label obtaining unit 133 obtains the second label described in the path message given in the previous node, and stores it in the second label next storage part in association with the identifier of the protection target LSP. Thereafter, processing in the LSP setting unit 15 is performed.

  FIG. 10 is a diagram showing extracted functional units that operate when the detour LSP setting control unit 13 receives a reserve message.

  10, the protection target LSP / detour LSP determination unit 134 determines whether the received reserve message is for the protection target LSP, the detour LSP, or the other, and the previous node / merge node determination unit 135, LSP setting unit Pass the result to 15. Based on the path information described in the reserve message, the previous node / merge node determination unit 135 determines that the current node is positioned immediately before the node to be protected and is determined to be a merge node if positioned next to the node to be protected. .

  If the reserve message is for the protection target LSP and the own node is the previous node, the process of the merge node detection unit 136 is performed. The merge node detection unit 136 detects a merge node from the path information described in the reserve message and stores it in the merge node storage unit. Thereafter, the process of the detour LSP setting unit 137 is performed. The bypass LSP setting unit 137 sets, for the detected merge node, a multicast LSP having the merge node as a leaf as a bypass LSP. Thereafter, processing in the LSP setting unit 15 is performed.

  If the reserve message is for the detour LSP and the own node is the previous node, the failure label table creation unit 138 performs failure label table creation processing, and then the merge node management unit 139 determines the number of merge nodes. Management etc. are performed. Thereafter, the processing of the LSP setting unit 15 is performed.

  If the reserve message is for the bypass LSP and the own node is a merge node, the process of the bypass label table creation unit 140 is performed. The detour label table creation unit 140 determines a transfer label (incoming label) for the detour route, and associates the second label stored in the second label-next storage unit with the label of the protection target LSP (out label). And store in the detour label table storage unit. Thereafter, processing in the LSP setting unit 15 is performed.

  Next, the configuration of the packet transfer control unit 14 will be described in detail with reference to FIG. As described above, the packet transfer control unit 14 operates only when a labeled packet is received.

  In FIG. 11, the transfer label table search unit 141 searches the transfer label table storage unit and the like using the top label of the received packet. Thereafter, processing by the label push unit 142, the label pop unit 143, the label swap unit 144, the second label search unit 145, and the pop-swap unit 146 is performed based on the contents of the top label and the label table.

  The label push unit 142 assigns the outgoing label written in the transfer label table storage unit to the packet as a top label and passes it to the packet transfer unit 16. The label pop unit 143 deletes the top label and passes it to the packet transfer unit 16. The label swap unit 144 replaces the top label with the outgoing label described in the transfer label table storage unit, and passes it to the packet transfer unit 16. The second label search unit 145 searches the detour label table storage unit using the top label and the second label, and passes the packet to the pop-swap unit 146 when there is matching association information. The pop-swap unit 146 removes the top label, swaps the second label to the outgoing label described in the detour label table storage unit, and passes it to the packet transfer unit 16.

<Second Embodiment>
Next, a second embodiment of the present invention will be described.

(System operation)
First, with reference to FIG. 12 and FIG. 13, an operation example of detour LSP setting and packet transfer in the second embodiment will be described.

  Here, as in the case of FIG. 6 of the first embodiment, the setting of the bypass LSP for the protection target LSP1 and the protection target LSP2 shown in FIG. 1B will be described.

  First, in the process of setting the protection target LSP1, a transfer label table of the protection target LSP1 is created at each node. That is, the first line of FIG. 13A is created at node A, and the first line of FIG. 13E is created at node D.

  The node A that has received the reserve message corresponding to the path message for setting the protection target LSP1 detects the merge node D by referring to the path information of the reserve message. Then, the node A that has detected the merge node D sets the multicast LSP to the node D as the bypass LSP4. That is, the detour route is determined, and the path message is transmitted including the protection target LSP1 identifier.

  The node D that has received the path message of the detour LSP4 stores the identifier of the protection target LSP1 in the storage means. Then, the node D that has received the reserve message for setting the bypass LSP4 from the downstream determines the label 16 that is the transfer label of the bypass LSP4, refers to the identifier of the protection target LSP1, and refers to the outgoing label 20 and label of the protection target LSP1. 16 is stored in the transfer label table (the bottom line in FIG. 13E).

  Then, in the process in which the reserve message for setting the bypass LSP4 is transferred upstream, the transfer label table of the bypass LSP4 of each node is set. The node A that has received the reservation message for setting the bypass LSP4 creates a failure label table in which the incoming label of the protection target LSP1 is associated with the outgoing label of the bypass LSP4 (first line in FIG. 13B). ).

  The same applies to the protection target LSP2. However, unlike the first embodiment, a multicast bypass LSP3 is set for the protection target LSP2 separately from the bypass LSP4. That is, a multicast LSP with a merge node as a leaf is set for each protection target LSP. As a result, the tables shown in FIGS. 13A to 13F are created. For example, in node C, which is a merge node and branch node, the output label 12 is associated with the input label 11 of the detour LSP 3 and the output label 30 of the protection target LSP 2 is associated with the input label 11.

  Next, an operation when a failure occurs in the node Z that is the protection target node will be described with reference to FIG.

  When a failure occurs in the node Z, the reference destination is switched from the normal transfer label table shown in FIG. 12A to the failure time label table shown in FIG.

  The node A that has received the packet of the protection target LSP1 to which the label 17 is assigned searches the FIG. 13B, swaps the label 17 to the label 14, and transfers it to the node B. Node B swaps label 14 with label 15 and transfers it to node C using the transfer label table shown in FIG. The node C refers to the transfer label table shown in FIG. 13D, swaps the label 15 with the label 16, and transfers it to the node D.

  The node D that has received the packet with the label 16 refers to the transfer label table of FIG. 13 (e), swaps the label 16 with the label 20, and transfers it downstream of the protection target LSP1.

  Next, a case where a packet of the protection target LSP2 with the label 25 is received will be described.

  The node A that has received the packet of the protection target LSP2 to which the label 25 is assigned searches the FIG. 13B, swaps the label 25 to the label 10, and transfers it to the node B. Node B swaps label 10 to label 11 and transfers it to node C using the transfer label table shown in FIG. The node C refers to the transfer label table shown in FIG. 13D, copies the packet, swaps the label 11 to the label 12 and transfers it to the node D, and swaps the label 11 to the label 30. The operation of transferring to the downstream of the protection target LSP2 is performed.

  The node D that has received the packet with the label 12 refers to the transfer label table of FIG. 13E, copies the packet, swaps the label 12 to the label 13, and transfers it to the node E. The operation of swapping the label 12 with the label 31 and transferring it downstream of the protection target LSP 2 is performed.

  The node E that has received the packet with the label 13 refers to the transfer label table of FIG. 13 (f), swaps the label 13 to the label 32, and transfers it downstream of the protection target LSP2.

(About device configuration)
Next, a functional configuration of the transmission apparatus configuring the node in the present embodiment will be described. FIG. 14 is a block diagram illustrating a functional configuration of the transmission apparatus 20 according to the present embodiment.
As shown in FIG. 14, the transmission apparatus 20 according to the present embodiment has the same configuration as that of the first embodiment. A transfer control unit 24, an LSP setting unit 25, a packet transfer unit 26, and a storage unit 27 are included. The function of each part is the same as that of the first embodiment except for the points described below. The storage unit 27 includes a protection target LSP identifier storage unit, a merge node storage unit, a failure label table storage unit, and a transfer label table storage unit.

  The configurations of the bypass LSP setting control unit 23 and the packet transfer control unit 24 will be described in more detail with reference to FIGS. 15, 16, and 17.

  FIG. 15 is a diagram showing an extracted function unit that operates when the bypass LSP setting control unit 23 receives a path message.

  In FIG. 15, the protection target LSP / detour LSP determination unit 230 determines whether the received path message is for the detour LSP or not, and if it is for the detour LSP, performs processing on the previous node / merge node determination unit 231. Transfer. If it is not for the detour LSP, the process moves to the LSP setting unit 25. Based on the route information described in the path message, the previous node / merge node determination unit 231 determines that the current node is located immediately before the node to be protected, and is determined to be a merge node if located next. . If it is a merge node, the protection target LSP identifier acquisition unit 232 performs processing.

  The protection target LSP identifier acquisition unit 232 acquires the protection target LSP identifier from the path message and stores it in the protection target LSP identifier storage unit. Thereby, it is possible to determine that the bypass LSP set by the path message is for the protection target LSP identified by the protection target LSP identifier. Thereafter, the processing is transferred to the LSP setting unit 25.

  FIG. 16 is a diagram showing extracted functional units that operate when the detour LSP setting control unit 23 receives a reserve message.

  In FIG. 16, the protection target LSP / bypass LSP determination unit 233 determines whether the received reserve message is for the protection target LSP, the detour LSP, or the other, and the previous node / merge node determination unit 234, the LSP setting unit Pass the result to 25. Based on the path information described in the reserve message, the previous node / merge node determination unit 234 determines that the current node is located immediately before the node to be protected and is determined to be a merge node if located next to the node to be protected. .

  If the reserve message is for the protection target LSP and the own node is the previous node, the process of the merge node detection unit 235 is performed. The merge node detection unit 235 detects the merge node from the route information described in the reserve message and stores it in the merge node storage unit. Thereafter, the process of the detour LSP setting unit 236 is performed. The bypass LSP setting unit 236 sets, for the detected merge node, a multicast LSP having each merge node as a leaf as a bypass LSP. That is, processing necessary to transmit a path message including the protection target LSP identifier is performed. Thereafter, processing in the LSP setting unit 25 is performed.

  If the reserve message is for the bypass LSP and the own node is the previous node, the fault label table creation unit 237 associates the incoming label of the protection target LSP with the output label of the bypass LSP, thereby generating the fault label table. It is created and stored in the failure label table storage unit. Subsequently, the merge node management unit 238 acquires merge nodes from the reserve message and grasps the increase / decrease in the number of merge nodes. Thereafter, processing of the LSP setting unit 25 is performed.

  If the reserve message is for the bypass LSP and the own node is a merge node, the process of the bypass label table creation unit 239 is performed. The detour label table creation unit 239 associates the incoming label of the detour LSP with the protection target LSP, and stores it in the transfer label table storage unit as detour data. Thereafter, processing in the LSP setting unit 25 is performed.

  Next, the configuration of the packet transfer control unit 24 will be described in detail with reference to FIG. As described above, the packet transfer control unit 24 operates only when a labeled packet is received.

  In FIG. 17, the transfer label table search unit 241 searches the transfer label table storage unit using the top label of the received packet. Thereafter, processing by the label push unit 242, the label pop unit 243, and the label swap unit 244 is performed based on the contents of the top label and the label table, and the packet is transferred to the packet transfer unit 26. Here, before failure detection, all nodes refer to the transfer label table for label transfer, and when a failure is detected, the previous node refers to the failure label table for label transfer, and other nodes Performs label transfer using the transfer label table.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a technique for bypassing a route at high speed when a node failure occurs in a multicast MPLS communication network.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made within the scope of the claims.

It is a figure for demonstrating the high speed detour LSP setting method at the time of a node failure in a prior art. It is a figure for demonstrating the high speed detour LSP setting method at the time of a node failure in a prior art. It is a flowchart which shows the operation | movement outline | summary of the node in 1st Embodiment (when a path message is received). It is a flowchart which shows the operation | movement outline | summary of the node in 1st Embodiment (when a reserve message is received). It is a flowchart which shows the operation | movement outline | summary of the node in 1st Embodiment (when the packet with a label is received). It is a figure for demonstrating operation | movement of the system in 1st Embodiment. It is a figure which shows the label table of each node in the case of FIG. It is a block diagram of the transmission apparatus in 1st Embodiment. It is a figure which extracts and shows the detailed structure of the detour LSP setting control part 13 at the time of receiving a path message. It is a figure which extracts and shows the detailed structure of the detour LSP setting control part 13 at the time of receiving a reserve message. FIG. 3 is a diagram illustrating in detail a configuration of a packet transfer control unit 14. It is a figure for demonstrating operation | movement of the system in 2nd Embodiment. It is a figure which shows the label table of each node in the case of FIG. It is a block diagram of the transmission apparatus in 2nd Embodiment. It is a figure which extracts and shows the detailed structure of the detour LSP setting control part 23 when a path message is received. It is a figure which extracts and shows the detailed structure of the detour LSP setting control part 23 at the time of receiving a reserve message. FIG. 3 is a diagram illustrating in detail a configuration of a packet transfer control unit 24.

Explanation of symbols

10, 20 Transmission device 11, 21 Packet receiving unit 12, 22 Packet analyzing unit 13, 23 Detour LSP setting control unit 14, 24 Packet transfer control unit 15, 25 LSP setting unit 16, 26 Packet transfer unit 17, 27 Storage unit

Claims (10)

A detour LSP (Label Switched Path) setting method for dealing with a node failure in an MPLS communication network configured by a multicast transmission device,
A step in which a previous node, which is a node immediately preceding the protection target node on the path of the protection target LSP, determines a label unique to the protection target LSP and notifies the downstream;
A merge node that is a node next to the protection target node on the path of the protection target LSP stores a label unique to the protection target LSP assigned by the previous node and an identifier of the protection target LSP;
After the setting of the protection target LSP is completed, the previous node detects a merge node;
A step in which the previous node performs processing for setting a multicast LSP having all detected merge nodes as a leaf as a bypass LSP in a route that does not pass through the protection target node;
After completing the setting of the bypass LSP, the merge node has a step of associating the incoming label of the bypass LSP, the label unique to the protection target LSP, and the output label of the protection target LSP based on the identifier of the protection target LSP. ,
In the event of a failure, the previous node stacks the protected LSP-specific label as a second label on the packet, forwards the packet to the detour LSP, and the merge node uses the top label and the second label of the received packet. A detour LSP setting method characterized by specifying an outgoing label of a protection target LSP and transferring the packet downstream of the protection target LSP. A detour LSP setting method for dealing with a node failure in an MPLS communication network configured by a multicast transmission device,
After the setting of the protection target LSP is completed, the previous node that is the previous node of the protection target node on the protection target LSP path detects the merge node that is the next node of the protection target node on the protection target LSP path. And steps to
The previous node determines a multicast LSP whose leaf is the detected merge node as a bypass LSP for each protection target LSP in a route that does not pass through the protection target node, and a path message including the identifier of the protection target LSP as a route of the bypass LSP Sending to
A merge node receiving a bypass LSP setting path message and storing an identifier of the protection target LSP;
After the setting of the bypass LSP is completed, the merge node has a step of associating the incoming label of the bypass LSP with the outgoing label of the protection LSP based on the identifier of the protection LSP;
In the event of a failure, the previous node transfers a packet of a certain protection target LSP to the detour LSP corresponding to the protection target LSP, and the merge node uses the top label of the received packet as the outgoing label of the protection target LSP. A detour LSP setting method characterized by identifying and transferring the packet downstream of the protection target LSP. A multicast MPLS transfer apparatus that constitutes an MPLS communication network capable of setting a detour LSP to cope with a node failure, and has a function as a previous node that is a node immediately preceding a protection target node on a path of the protection target LSP A multicast MPLS transfer device including:
Means for determining a label specific to the protection target LSP in the process of setting the protection target LSP and notifying the downstream;
Means for detecting a merge node that is the next node of the protection target node on the path of the protection target LSP after the setting of the protection target LSP;
Means for performing processing for setting a multicast LSP having all detected merge nodes as leaves as a detour LSP in a route not passing through the protection target node;
Means for associating and storing the incoming label of the protection target LSP, the label unique to the protection target LSP, and the outgoing label of the detour LSP as a label table at the time of failure;
When a packet of the protection target LSP is received at the time of failure, a means for referring to the label table at the time of failure, stacking the label unique to the protection target LSP as a second label on the packet, and transferring the packet to the bypass LSP is provided. A multicast MPLS transfer apparatus characterized by the above. A multicast MPLS transfer apparatus that constitutes an MPLS communication network capable of setting a detour LSP to cope with a node failure, and includes a function as a merge node that is the next node of the protection target node on the path of the protection target LSP An MPLS transfer device,
Means for storing, in the setting process of the protection target LSP, a label unique to the protection target LSP assigned by a previous node that is a node immediately preceding the protection target node on the path of the protection target LSP, and an identifier of the protection target LSP When,
After completing the setting of the bypass LSP determined by the previous node, based on the identifier of the protection target LSP, the input label of the bypass LSP, the label unique to the protection target LSP, and the output label of the protection target LSP are associated with each other. Means for storing as a label table;
When a packet in which a label unique to the protection target LSP is stacked as a second label is received from the detour LSP, the detour label table is referred to and the top label and the second label of the received packet are used to refer to the protection target LSP. A multicast MPLS transfer apparatus comprising: means for specifying an outgoing label and transferring the packet downstream of the protection target LSP. A multicast MPLS transfer apparatus that constitutes an MPLS communication network capable of setting a detour LSP to cope with a node failure, and has a function as a previous node that is a node immediately preceding a protection target node on a path of the protection target LSP A multicast MPLS transfer device including:
Means for detecting a merge node that is the next node of the protection target node on the path of the protection target LSP after the setting of the protection target LSP;
Means for determining a multicast LSP having a detected merge node as a leaf as a bypass LSP for each protection target LSP on a route not passing through the protection target node, and sending a path message including the identifier of the protection target LSP to the route of the bypass LSP When,
Means for associating and storing the incoming label of the protection target LSP and the outgoing label of the detour LSP as a failure time label table;
A multicast MPLS transfer apparatus comprising: means for referencing a failure label table when a packet of a protection target LSP is received at the time of failure, and transferring the packet to a detour LSP corresponding to the protection target LSP . A multicast MPLS transfer apparatus that constitutes an MPLS communication network capable of setting a detour LSP to cope with a node failure, and includes a function as a merge node that is the next node of the protection target node on the path of the protection target LSP An MPLS transfer device,
Means for receiving a path message for setting the detour LSP determined by the previous node, and acquiring and storing an identifier of the protection target LSP from the path message;
Means for associating the incoming label of the bypass LSP with the outgoing label of the protection target LSP based on the identifier of the protection target LSP after completion of the setting of the bypass LSP, and storing it as a bypass label table;
Means for referring to the detour label table, specifying the outgoing label of the protection target LSP using the top label of the received packet, and transferring the packet downstream of the protection target LSP when a packet is received from the detour LSP A multicast MPLS transfer apparatus comprising: A function as a previous node that is a node immediately preceding the protection target node on the path of the protection target LSP is realized in the multicast MPLS transfer apparatus constituting the MPLS communication network capable of setting the detour LSP to cope with the node failure. A multicast MPLS transfer device,
Means for determining a label unique to the protection target LSP in the process of setting the protection target LSP and notifying the downstream;
Means for detecting a merge node that is the next node of the protection target node on the path of the protection target LSP after completion of the setting of the protection target LSP;
Means for performing processing for setting a multicast LSP having all detected merge nodes as leaves as a detour LSP in a route not passing through the protection target node;
Means for associating the incoming label of the protection target LSP, the label unique to the protection target LSP, and the outgoing label of the detour LSP and storing them in the storage device as a failure time label table;
Means for referencing the failure label table when the packet of the protection target LSP is received at the time of failure, stacking the label unique to the protection target LSP on the packet as the second label, and transferring the packet to the detour LSP;
Program to function as. In order to realize a function as a merge node that is a node next to a protection target node on a path of the protection target LSP in a multicast MPLS transfer apparatus that configures an MPLS communication network capable of setting a detour LSP to cope with a node failure A multicast MPLS transfer device,
In the setting process of the protection target LSP, the label unique to the protection target LSP assigned by the previous node that is the node immediately before the protection target node on the path of the protection target LSP and the identifier of the protection target LSP are stored in the storage device. Means for storing,
After completing the setting of the bypass LSP determined by the previous node, based on the identifier of the protection target LSP, the input label of the bypass LSP, the label unique to the protection target LSP, and the output label of the protection target LSP are associated with each other. Means for storing in a storage device as a label table;
When a packet in which a label unique to the protection target LSP is stacked as a second label is received from the detour LSP, the detour label table is referred to and the top label and the second label of the received packet are used to refer to the protection target LSP. Means for identifying the outgoing label and forwarding the packet downstream of the protected LSP;
Program to function as. A function as a previous node that is a node immediately preceding the protection target node on the path of the protection target LSP is realized in the multicast MPLS transfer apparatus constituting the MPLS communication network capable of setting the detour LSP to cope with the node failure. A multicast MPLS transfer device,
Means for detecting a merge node that is the next node of the protection target node on the path of the protection target LSP after completion of the setting of the protection target LSP;
Means for determining a multicast LSP having a detected merge node as a leaf as a bypass LSP for each protection target LSP on a route not passing through the protection target node, and sending a path message including the identifier of the protection target LSP to the route of the bypass LSP ,
Means for associating the incoming label of the protection target LSP with the outgoing label of the detour LSP and storing it in the storage device as a failure label table;
A program that, when receiving a packet of the protection target LSP at the time of failure, refers to the label table at the time of failure and functions as a means for transferring the packet to the detour LSP corresponding to the protection target LSP. In order to realize a function as a merge node that is a node next to a protection target node on a path of the protection target LSP in a multicast MPLS transfer apparatus that configures an MPLS communication network capable of setting a detour LSP to cope with a node failure A multicast MPLS transfer device,
Means for receiving a path message for setting the bypass LSP determined by the previous node, obtaining an identifier of the protection target LSP from the path message, and storing the identifier in the storage device;
Means for associating the incoming label of the bypass LSP with the outgoing label of the protection target LSP based on the identifier of the protection target LSP after the setting of the bypass LSP is completed, and storing it in the storage device as a bypass label table;
Means for referring to the detour label table, specifying the outgoing label of the protection target LSP using the top label of the received packet, and transferring the packet downstream of the protection target LSP when a packet is received from the detour LSP ,
Program to function as.

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