Per-Group ECMP for Multidestination Traffic in DCE/TRILL Networks

• US 20130083660A1
• Filed: 10/03/2011
• Published: 04/04/2013
• Est. Priority Date: 10/03/2011
• Status: Abandoned Application

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Balasubramanian, Hariharan, Kulhari, Ajay, Rajagopalan, Santosh
• Application Number:
  US13/251,957
• Publication Number:
  US 20130083660A1
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 45/245 Link aggregation, e.g. trunking
• CPC Class Codes: H04L 45/32 Flooding denial of service attacks H04L63/1458
• CPC Class Codes: H04L 45/66 Layer 2 routing, e.g. in Ethernet based MAN's
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Consistent with embodiments of the present disclosure, systems and methods are disclosed for providing per-group ECMP for multidestination traffic in a DCE/TRILL network. Embodiments enable per-group load balancing of multidestination traffic in DCE/L2MP networks by creating a new IS-IS PDU to convey the affinity of the parent node for a given multicast group. For broadcast and unknown unicast flooded traffic, the load balancing may be done on a per-vlan basis.

Claims

1. A method comprising:

obtaining a unicast ECMP graph;

identifying available paths for a plurality of network devices from the unicast ECMP graph;

identifying parents for each of the identified network devices;

obtaining group membership information for each of the identified network devices;

informing the identified parents of chosen group parent information derived from the group membership information;

flooding chosen group parent information via group membership LSP (“

GM-LSP”

); and

enforcing selection of group information through forwarding constructs.

2. The method of claim 1, further comprising obtaining group membership information using local policy information via one of:

IGMP or MLD.

3. The method of claim 1, further comprising dynamically adjusting chosen group parent information upon notification of a change in the unicast ECMP graph.

4. The method of claim 1, further comprising sending a GPS-PDU between each of the plurality of network devices and their respective associated parent network devices.

5. The method of claim 4, further comprising each of the plurality of network devices selecting an associated parent network device to accept traffic for a designated group.

6. The method of claim 5, further comprising masking the address associated with the designated group.

7. The method of claim 1, further comprising ensuring that each of the plurality of network devices has only one associated parent network device for a given source switch.

8. The method of claim 7, further comprising forwarding the only one associated parent network device information for a given source switch.

9. A network device comprising:

a processor configured to;

obtain a unicast ECMP graph;

perform load balancing based on a hash packet associated with the unicast ECMP graph;

select a unicast path based on load balancing; and

determine per-group based on the unicast ECMP graph which of a plurality of parent switches can send traffic directed to each group such that a single parent switch exists for each source switch.

10. The network device of claim 9, wherein the processor is further configured to add an outgoing interface to a tree associated with the determined parent switch.

11. The network device of claim 10, wherein the processor is further configured to add a PDU extension to an IS-IS protocol.

12. A method comprising:

establishing a first PDU extension;

flooding information associated with the first PDU extension to a plurality of switches in a network, wherein each of the plurality of switches has interested multicast receivers for a first group; and

indicating via PDU information which of a plurality of parent switches should send traffic associated with a given multicast address.

13. The method of claim 12, further comprising establishing an identifier that alerts switching devices that an enhanced protocol is employed.

14. The method of claim 13, further comprising storing the identifier in space reserved for TRILL nicknames.

15. The method of claim 12, further comprising computing an outgoing interface list at an intermediate parent switch.

16. The method of claim 15, wherein the outgoing interface list only includes an ECMP path signaled by the PDU.

17. The method of claim 16, further comprising modifying one of:

an incoming interface check or a reverse path forwarding check.

18. The method of claim 17, wherein the modification of one of:

the incoming interface check or the reverse path forwarding check results in the check being done on a per-multicast group/per-source switch basis.

19. The method of claim 12, further comprising receiving multicast packets for a multidestination group, wherein the multicast packets share an identical group address.

20. The method of claim 19, further comprising selecting a parent switch for the identical group address based on VLAN information associated with the group.