PREVENTING TRAFFIC FLOODING TO THE ROOT OF A MULTI-POINT TO MULTI-POINT LABEL-SWITCHED PATH TREE WITH NO RECEIVERS

• US 20090271467A1
• Filed: 04/23/2008
• Published: 10/29/2009
• Est. Priority Date: 04/23/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Boers, Arjen, Wijnands, IJsbrand
• Granted Patent: US 8,804,718 B2
• Time in Patent Office: Days
• US Class Current: 709/201
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]

Abstract

A method is provided for pruning an MP2MP tree. The method includes (a) in a first node of an MP2MP LSP tree, the MP2MP LSP tree including a plurality of nodes, determining whether the first node has only a single replication branch for the MP2MP LSP tree, the single replication branch representing a downstream path to only a second node of the plurality of nodes, (b) in response to determining that the first node has only a single replication branch for the MP2MP LSP tree, sending a message to the second node indicating that the second node should refrain from sending upstream traffic towards the first node, and (c) in response to determining that the first node does not have only a single replication branch for the MP2MP LSP tree, refraining from sending a message to the second node indicating that the second node should refrain from sending upstream traffic of the MP2MP LSP tree towards the first node. Apparatus are also provided for use in practicing certain embodiments.

Claims

1. A method comprising:

in a first node of a multipoint-to-multipoint (MP2MP) label switched path (LSP) tree, the MP2MP LSP tree including a plurality of nodes, determining whether the first node has only a single replication branch for the MP2MP LSP tree, the single replication branch representing a downstream path to only a second node of the plurality of nodes;

in response to determining that the first node has only a single replication branch for the MP2MP LSP tree, sending a message to the second node indicating that the second node should refrain from sending upstream traffic of the MP2MP LSP tree towards the first node; and

in response to determining that the first node does not have only a single replication branch for the MP2MP LSP tree, refraining from sending a message to the second node indicating that the second node should refrain from sending upstream traffic of the MP2MP LSP tree towards the first node.

2. A method as in claim 1 wherein the method further comprises:

subsequently determining, in the first node, whether the first node has a second replication branch for the MP2MP LSP tree, the second replication branch representing a path to a third node of the plurality of nodes;

in response to determining that the first node has a second replication branch for the MP2MP LSP tree, sending a message to the second node indicating that the second node should henceforth send upstream traffic towards the first node; and

in response to determining that the first node does not have a second replication branch for the MP2MP LSP tree, refraining from sending a message to the second node indicating that the second node should henceforth send upstream traffic towards the first node

3. A method as in claim 2:

wherein the method further comprises in response to determining that the first node has only a single replication branch for the MP2MP LSP tree, storing connection information for the second node in memory; and

wherein sending the message to the second node indicating that the second node should henceforth send upstream traffic towards the first node includes retrieving the connection information for the second node from memory.

4. A method as in claim 2 wherein determining whether the first node has a second replication branch is performed in response to receiving, at the first node, a request for a label mapping.

5. A method as in claim 1 wherein determining whether the first node has only a single replication branch is performed in response to receiving, at the first node, a request for a label mapping.

6. A method as in claim 1 wherein determining whether the first node has only a single replication branch is performed in response to receiving, at the first node, a message indicating that the first node should refrain from sending traffic towards a third node of the plurality of nodes.

7. An apparatus comprising:

a plurality of network interfaces; and

a controller, the controller being constructed and arranged to;

determine whether a first node of a multipoint-to-multipoint (MP2MP) label switched path (LSP) tree, the MP2MP LSP tree including a plurality of nodes, has only a single replication branch for the MP2MP LSP tree, the single replication branch representing a downstream path to only a second node of the plurality of nodes;

in response to determining that the first node has only a single replication branch for the MP2MP LSP tree, send a message over a network interface of the plurality of network interfaces to the second node indicating that the second node should refrain from sending upstream traffic towards the first node; and

in response to determining that the first node does not have only a single replication branch for the MP2MP LSP tree, refrain from sending a message over a network interface of the plurality of network interfaces to the second node indicating that the second node should refrain from sending upstream traffic towards the first node.

8. An apparatus as in claim 7 wherein the controller is further constructed and arranged to:

subsequently determine whether the first node has a second replication branch for the MP2MP LSP tree, the second replication branch representing a path to a third node of the plurality of nodes;

in response to determining that the first node has a second replication branch for the MP2MP LSP tree, send a message to the second node indicating that the second node should henceforth send upstream traffic towards the first node; and

in response to determining that the first node does not have a second replication branch for the MP2MP LSP tree, refrain from sending a message to the second node indicating that the second node should henceforth send upstream traffic towards the first node.

9. An apparatus as in claim 8 wherein:

the apparatus further includes memory;

the controller is further constructed and arranged to in response to determining whether the first node has only a single replication branch for the MP2MP LSP tree, store connection information for the second node in memory; and

the controller, when sending the message to the second node indicating that the second node should henceforth send upstream traffic towards the first node, is constructed and arranged to retrieve the connection information for the second node from memory.

10. An apparatus as in claim 8 wherein the controller is constructed and arranged to determine whether the first node has a second replication branch in response to receiving, over a network interface of the plurality of network interfaces, a request for a label mapping.

11. An apparatus as in claim 7 wherein the controller is constructed and arranged to determine whether the first node has only a single replication branch in response to receiving, over a network interface of the plurality of network interfaces, a request for a label mapping.

12. An apparatus as in claim 7 wherein the controller is constructed and arranged to determine whether the first node has only a single replication branch in response to receiving, over a network interface of the plurality of network interfaces, a message indicating that the first node should refrain from sending traffic towards a third node of the plurality of nodes.

13. An apparatus as in claim 7 wherein the controller is a microprocessor programmed to perform the claimed operations.

14. An apparatus as in claim 7 wherein the controller is a set of circuitry configured to perform the claimed operations.

15. An apparatus comprising:

a plurality of network interfaces; and

means for;

causing the apparatus to serve as a first node of a multipoint-to-multipoint (MP2MP) label switched path (LSP) tree, the MP2MP LSP tree including a plurality of nodes;

determining whether a first node of a multipoint-to-multipoint (MP2MP) label switched path (LSP) tree, the MP2MP LSP tree including a plurality of nodes, has only a single replication branch for the MP2MP LSP tree, the single replication branch representing a downstream path to only a second node of the plurality of nodes;

in response to determining that the first node has only a single replication branch for the MP2MP LSP tree, sending a message over a network interface of the plurality of network interfaces to the second node indicating that the second node should refrain from sending upstream traffic towards the first node; and

in response to determining that the first node does not have only a single replication branch for the MP2MP LSP tree, refraining from sending a message over a network interface of the plurality of network interfaces to the second node indicating that the second node should refrain from sending upstream traffic towards the first node.

16. An apparatus as in claim 15 wherein the apparatus further contains means for:

subsequently determining whether the first node has a second replication branch for the MP2MP LSP tree, the second replication branch representing a path to a third node of the plurality of nodes;

in response to determining that the first node has a second replication branch for the MP2MP LSP tree, sending a message to the second node indicating that the second node should henceforth send upstream traffic towards the first node; and

in response to determining that the first node does not have a second replication branch for the MP2MP LSP tree, refraining from sending a message to the second node indicating that the second node should henceforth send upstream traffic towards the first node.

17. An apparatus as in claim 16 wherein:

the apparatus further includes memory; and

the apparatus further comprises means for;

in response to determining that the first node has only a single replication branch for the MP2MP LSP tree, storing connection information for the second node in memory; and

when sending the message to the second node indicating that the second node should henceforth send upstream traffic towards the first node, retrieving the connection information for the second node from memory.

18. An apparatus as in claim 16 wherein the means for determining whether the first node has a second replication branch performs that operation in response to receiving, over a network interface of the plurality of network interfaces, a request for a label mapping.

19. An apparatus as in claim 15 wherein the means for determining whether the first node has a second replication branch performs that operation in response to receiving, over a network interface of the plurality of network interfaces, a request for a label mapping.

20. An apparatus as in claim 15 wherein the means for determining whether the first node has only a single replication branch performs that operation in response to receiving, over a network interface of the plurality of network interfaces, a message indicating that the first node should refrain from sending traffic towards a third node of the plurality of nodes.