METHOD TO TRANSPORT BIDIR PIM OVER A MULTIPROTOCOL LABEL SWITCHED NETWORK

• US 20080298360A1
• Filed: 05/23/2008
• Published: 12/04/2008
• Est. Priority Date: 05/29/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Boers, Arjen, Wijnands, Jacob Ijsbrand
• Granted Patent: US 8,391,185 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]

Abstract

A method, system and an apparatus to transport bidir PIM over a multiprotocol label switched network is provided. The method may comprise receiving a multicast packet at a network element, the multicast packet including an upstream label. The method may further comprise identifying, from the upstream label, a Multicast Distribution Tree (MDT) rooted a rendezvous point. The packet may be forwarded along the MDT towards the RP based on the upstream label. The MDT may be identified from a downstream label and the packet may be forwarded the along the MDT away from the RP based on the downstream label.

Claims

1. A method comprising:

receiving a multicast packet at a network element, the multicast packet including an upstream label;

identifying, from the upstream label, a Multicast Distribution Tree (MDT) rooted at a rendezvous point (RP); and

forwarding the packet along the MDT towards the RP based on the upstream label.

2. The method of claim 1, further comprising:

identifying the MDT from a downstream label; and

forwarding the packet the along the MDT away from the RP based on the downstream label.

3. The method of claim 1, wherein the multicast packet is a bidirectional Protocol Independent Multicast (bidir PIM) packet.

4. The method of claim 1, further comprising building the MDT using a Label Switched Path (LSP) rooted at an ingress provider edge router element in a network.

5. The method of claim 4, wherein the MDT is a point-to-multipoint (P2MP) LSP or a multipoint-to-multipoint (MP2MP) LSP.

6. The method of claim 4, further comprising:

performing a route lookup at each of a plurality of edge router elements of the network; and

selecting one of the plurality edge router elements as the root of a LSP tree of a MDT based on the lookup.

7. The method of claim 4, wherein the MDT tree extends from the ingress provider edge router element to the RP to form a segmented MDT.

8. The method of claim 1, further comprising creating one downstream state and multiple upstream states at provider edge router elements of a network, wherein each provider edge router element acts as a label switched router configured to forward packets based on the upstream label and downstream labels.

9. The method of claim 1, further comprising aggregating Multiple Virtual Private Networks (VPNs) over the MDT, and wherein an ingress provider edge router element allocates a label per VPN.

10. The method claim 1, further comprising:

receiving a bidir PIM interest on a VPN interface of a provider edge router element;

performing a unicast route lookup on the RP and selecting an ingress provider edge router element as the root of the MDT;

identifying a multipoint-to-multipoint tree identifier from the root of the MDT; and

using the multipoint-to-multipoint tree identifier as a Forwarding Equivalence Class (FEC).

11. The method of claim 10, further comprising:

looking up a reverse path forward neighbor for the RP;

building the MDT;

installing the upstream label in a global table of the provider edge router element; and

unicasting a PIM join to a router element associated with the RP.

12. An apparatus comprising:

memory to store instructions; and

a processor configured to execute the instructions to;

receive a multicast packet at a network element, the multicast packet including an upstream label;

identify, from the upstream label, a Multicast Distribution Tree (MDT) rooted at a rendezvous point (RP); and

forward the packet along the MDT towards the RP based on the upstream label.

13. The apparatus of claim 12, wherein the MDT is identified from a downstream label and the packet is forwarded the along the MDT away from the RP based on the downstream label.

14. The apparatus of claim 12, wherein the multicast packet is a bidirectional Protocol Independent Multicast (bidir PIM) packet.

15. The apparatus of claim 12, wherein the MDT is built using a Label Switched Path (LSP) rooted at an ingress provider edge router element in a network.

16. The apparatus of claim 15, wherein the MDT is a point-to-multipoint (P2MP) LSP or a multipoint-to-multipoint (MP2MP) LSP.

17. The apparatus of claim 15, wherein the instructions cause the processor to:

perform a route lookup at each of a plurality of edge router elements of the network; and

select one of the plurality edge router elements as the root of a LSP tree of a MDT based on the lookup.

18. The apparatus of claim 15, wherein the MDT tree extends from the ingress provider edge router element to the RP to form a segmented MDT.

19. The apparatus of claim 12, wherein the instructions cause the processor to create one downstream state and multiple upstream states at provider edge router elements of a network, wherein each provider edge router element acts as a label switched router configured to forward packets based on the upstream label and downstream labels.

20. The apparatus of claim 12, wherein the instructions cause the processor to aggregate Multiple Virtual Private Networks (VPNs) over the MDT, and wherein an ingress provider edge router element allocates a label per VPN.

21. The apparatus claim 12, wherein the instructions cause the processor to:

receive a bidir PIM interest on a VPN interface of a provider edge router element;

perform a unicast route lookup on the RP and selecting an ingress provider edge router element as the root of the MDT;

identify a multipoint-to-multipoint tree identifier from the root of the MDT; and

use the multipoint-to-multipoint tree identifier as a Forwarding Equivalence Class (FEC).

22. The apparatus of claim 21, wherein the instructions cause the processor to:

look up a reverse path forward neighbor for the RP;

build the MDT;

install the upstream label in a global table of the provider edge router element; and

unicast a PIM join to a router element associated with the RP.

23. An apparatus comprising:

means for receiving a multicast packet at a network element, the multicast packet including an upstream label;

means for identifying, from the upstream label, a Multicast Distribution Tree (MDT) rooted at a rendezvous point (RP); and

means for forwarding the packet along the MDT towards the RP based on the upstream label.