ROOT NODE REDUNDANCY FOR MULTIPOINT-TO-MULTIPOINT TRANSPORT TREES

• US 20110058567A1
• Filed: 11/12/2010
• Published: 03/10/2011
• Est. Priority Date: 02/02/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Lo, Alton, Boers, Arjen, Wijnands, Ijsbrand
• Granted Patent: US 8,953,604 B2
• Time in Patent Office: Days
• US Class Current: 370/401
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04L 45/484 using multiple routing trees
• CPC Class Codes: H04L 45/488 using root node determination
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering

Abstract

A mechanism is provided to configure a plurality of transport trees in a transport network, each of which correspond to a native tree (e.g., a bidirectional multicast tree). In embodiments of the present invention, each of the plurality of transport trees has a unique root node so that in the event of a failure of any root node, the transport trees with surviving root nodes can be used to transport traffic from the native tree. The present invention provides for each transport network edge router being independently responsible for selection of a transport tree that the edge router will use to transmit a datastream, while also being capable of receiving packets from any transport tree. Through the use of such configured transport trees along with independent selection of a transport tree, the present invention provides a reduction in the disruption of datastream transmission due to a root node failure.

Claims

1. A method comprising:

configuring a first transport tree having an associated first root node, wherein

the first transport tree is configured to transport a datastream to a plurality of edge nodes of a transport network through the first root node;

configuring a second transport tree having an associated second root node, wherein

the second transport tree is configured to transport the datastream to the plurality of edge nodes through the second root node;

determining whether the first root node is unavailable; and

selecting one of the first transport tree and the second transport tree to transmit the datastream, wherein said selecting comprises selecting the second transport tree in response to determining that the first root node is unavailable.

2. The method of claim 1 further comprising:

receiving routing information that the first root node is unavailable; and

performing said determining whether the first root node is unavailable using the routing information.

3. The method of claim 1 wherein an MPLS network comprises the first and second transport trees.

4. The method of claim 3 wherein the first and second root nodes are core routers in the MPLS network.

5. The method of claim 1 further comprising:

associating a first transport tree identifier with the first transport tree, wherein

the first transport tree identifier is generated using an identifier for the first root node.

6. The method of claim 5 wherein the first transport tree identifier is further generated using one or more identifiers for the datastream.

7. The method of claim 1, wherein

said configuring the first transport tree comprises selecting the first root node, forming a first transport tree identifier, and initiating a build of the first transport tree;

and

said configuring the second transport tree comprises selecting the second root node, forming a second transport tree identifier, and initiating a build of the second transport tree.

8. The method of claim 1, wherein

the first transport tree is a multipoint-to-multipoint transport tree through the transport network;

the second transport tree is a multipoint-to-multipoint transport tree through the transport network;

the first root node is logically upstream from all other nodes in the first transport tree;

the second root node is logically upstream from all other nodes in the second transport tree; and

the first root node is distinct from the second root node.

9. A transport network edge router comprising:

a plurality of network line cards, wherein

a first network line card of the plurality of network line cards is configured to transmit a datastream on a selected transport tree; and

a processor coupled to the first network line card, wherein the processor is configured to

initiate configuration of a first transport tree having an associated first root node, wherein

the first transport tree is configured to transport the datastream to a plurality of edge nodes of a transport network through the first root node,

initiate configuration of a second transport tree having an associated second root node, wherein

the second transport tree is configured to transport the datastream to the plurality of edge nodes through the second root node,

determine whether the first root node is unavailable, and

select the selected transport tree from the first transport tree and the second transport tree, wherein the processor is further configured to select the second transport tree in response to determining that the first root node is unavailable.

10. The transport network edge router of claim 9 further comprising:

the processor further configured to

receive routing information that the first root node is unavailable, and

use the routing information in performing said determination that the first root node is unavailable.

11. The transport network edge router of claim 9, wherein

the transport network edge router is a member of an MPLS network;

and

the MPLS network comprises the first and second transport trees, wherein

the first and second root nodes are core routers in the MPLS network.

12. The transport network edge router of claim 9 further comprising:

the processor further configured to

generate a first transport tree identifier using an identifier for the first root node, and

associate the first transport tree identifier with the first transport tree.

13. The transport network edge router of claim 12 further comprising:

the processor further configured to

generate the first transport tree identifier using one or more identifiers for the datastream.

14. The transport network edge router of claim 9 further comprising:

the processor further configured to initiate configuration of the first transport tree by

being further configured to

select the first root node,

form a first transport tree identifier, and

initiate a build of the first transport tree; and

the processor further configured to initiate configuration of the second transport tree by

being further configured to

select the second root node,

form a second transport tree identifier, and

initiate a build of the second transport tree.

15. An apparatus comprising:

a plurality of network line cards, wherein

a first network line card of the plurality of network line cards is configured to transmit a datastream on a selected transport tree;

means for initiating configuration of a first transport tree having an associated first root node, wherein

the first transport tree is configured to transport the datastream to a plurality of edge nodes of a transport network through the first root node;

means for initiating configuration of a second transport tree having an associated second root node, wherein

the second transport tree is configured to transport the datastream to the plurality of edge nodes of a transport network through the second root node;

means for determining whether the first root node is unavailable; and

means for selecting the selected transport tree from the first transport tree and the second transport tree, wherein the means for selecting the selected transport tree is responsive to the means for determining whether the first root node is unavailable.

16. The apparatus of claim 15 further comprising:

means for receiving routing information that the first root node is unavailable; and

the means for determining whether the first root node is unavailable further comprises means for using the routing information.

17. The apparatus of claim 15 wherein an MPLS network comprises the first and second transport trees.

18. The apparatus of claim 17 wherein the first and second root nodes are core routers in the MPLS network.

19. The apparatus of claim 15 further comprising:

means for generating a first transport tree identifier using an identifier of the first root node; and

means for associating the first transport tree identifier with the first transport tree.

20. The apparatus of claim 19 further comprising:

means for generating the first transport tree identifier using one or more identifiers for the datastream in addition to the identifier of the first root node.