ECMP Parent Group Selection for Multidestination Traffic in DCE/TRILL Networks

• US 20160080162A1
• Filed: 11/24/2015
• Published: 03/17/2016
• Est. Priority Date: 10/03/2011
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Rajagopalan, Santosh, Kulhari, Ajay, Balasubramanian, Hariharan
• Granted Patent: US 9,876,649 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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;

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

informing parents of each of the plurality of network device of chosen group parent information derived from the group membership information;

flooding the chosen group parent information via group membership (“

GM-LSP”

); and

enforcing selection of group parent information through forwarding constructs.

2. The method of claim 1, further comprising:

obtaining the group membership information using local policy information via one of;

IGMP or MLD.

3. The method of claim 1, further comprising:

dynamically adjusting the 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 parents.

5. The method of claim 4, further comprising:

selecting an associated parent to accept traffic for a designated group for each of the plurality of network devices.

6. The method of claim 5, further comprising:

masking an 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 for a given source switch.

8. The method of claim 7, further comprising:

forwarding the only one associated parent network device information to a second switch.

9. A network device comprising:

a memory

a processor configured to execute instructions stored in the memory, the instructions comprising;

obtaining a unicast ECMP graph; and

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

10. The network device of claim 9, wherein the instructions further comprise:

adding an outgoing interface to a tree associated with the single parent switch.

11. The network device of claim 9, wherein the instructions further comprise:

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

selecting a unicast path based on the load balancing.

12. The network device of claim 9, wherein the instructions further comprise:

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

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

13. The network device of claim 9, wherein the instructions further comprise:

maintaining an outgoing interface list at an intermediate parent switch.

14. The network device of claim 9, wherein the outgoing interface list only includes an ECMP path signaled by a PDU extension.

15. The network device of claim 9, wherein the instructions further comprise:

modifying an incoming interface check on a per-multicast group/per-source switch basis.

16. The network device of claim 9, wherein the instructions further comprise:

modifying a reverse path forwarding check on a per-multicast group/per-source switch basis.

17. A network device comprising:

a memory

a processor configured to execute instructions stored in the memory, the instructions comprising;

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

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

informing parents of each of the plurality of network device of chosen group parent information derived from the group membership information;

flooding the chosen group parent information via group membership (“

GM-LSP”

); and

enforcing selection of group parent information through forwarding constructs.

18. The network device of claim 17, wherein the instructions further comprise:

dynamically adjusting the chosen group parent information upon notification of a change in the unicast ECMP graph.

19. The network device of claim 17, wherein the instructions further comprise:

selecting an associated parent to accept traffic for a designated group for each of the plurality of network devices.

20. The network device of claim 17, wherein the instructions further comprise:

ensuring that each of the plurality of network devices has only one associated parent for a given source switch.