Scalable gateways for a fabric switch

1. A switch, comprising:

gateway subgroup circuitry configured to operate the switch in conjunction with a remote switch to form a gateway subgroup, wherein the switch and the remote switch actively operate as tunnel gateways;

tunnel management circuitry configured to maintain a data structure indicating whether a tunnel source subnet is associated with the gateway subgroup; and

packet processing circuitry configured to:

decapsulate a tunnel-encapsulated packet in response to a tunnel source subnet of the tunnel-encapsulated packet being associated with the gateway subgroup; and refrain from decapsulating the tunnel-encapsulated packet in response to the tunnel source subnet of the tunnel-encapsulated packet not being associated with the gateway subgroup.

2. The switch of claim 1 , further comprising handover circuitry configured to determine an egress port corresponding to a gateway switch, wherein the gateway switch is in a second gateway subgroup associated with the tunnel source subnet of the tunnel-encapsulated packet.

3. The switch of claim 1 , wherein the switch and the remote switch operate as a virtual gateway, wherein a tunnel destination of the tunnel-encapsulated packet is assigned to the virtual gateway.

4. The switch of claim 1 , wherein the packet processing circuitry is further configured to identify a virtual switch identifier in a packet as a local identifier assigned to the switch, wherein the virtual switch identifier is associated with a virtual switch.

5. The switch of claim 1 , wherein the packet processing circuitry is further configured to decapsulate a tunnel encapsulation header of the tunnel-encapsulated packet, wherein the tunnel-encapsulated packet is further encapsulated in a second encapsulation header.

6. The switch of claim 1 , further comprising multi-destination management circuitry configured to operate the switch as a designated forwarder of the gateway subgroup, wherein a designated forwarder forwards a multi-destination packet via edge ports of a switch.

7. The switch of claim 1 , further comprising multi-destination management circuitry configured to operate the switch as a designated forwarder of a gateway instance, wherein a gateway instance represents a gateway, and wherein a gateway instance includes one or more gateway subgroups.

8. The switch of claim 7 , wherein the switch and the remote switch operate as a virtual gateway for the gateway instance, wherein a gateway instance is associated with a virtual gateway.

9. The switch of claim 1 , further comprising fabric switch management circuitry configured to maintain a membership in a network of interconnected switches, wherein the network of interconnected switches is controlled as a single logical switch.

10. The switch of claim 1 , wherein the packet processing circuitry is further configured to continue to decapsulate a tunnel-encapsulated packet in response to determining that the remote switch is unavailable, wherein a tunnel source subnet of the tunnel-encapsulated packet being associated with the gateway subgroup.

11. A computer-executable method, comprising:

operating a switch in conjunction with a remote switch to form a gateway subgroup, wherein the switch and the remote switch actively operate as tunnel gateways;

maintaining a data structure indicating whether a tunnel source subnet is associated with the gateway subgroup;

decapsulating a tunnel-encapsulated packet in response to a tunnel source subnet of the tunnel-encapsulated packet being associated with the gateway subgroup; and

refraining from decapsulating the tunnel-encapsulated packet in response to the tunnel source subnet of the tunnel-encapsulated packet not being associated with the gateway subgroup.

12. The method of claim 11 , further comprising determining an egress port corresponding to a gateway switch, wherein the gateway switch is in a second gateway subgroup associated with the tunnel source subnet of the tunnel-encapsulated packet.

13. The method of claim 11 , wherein the switch and the remote switch operate as a virtual gateway, wherein a tunnel destination of the tunnel-encapsulated packet is assigned to the virtual gateway.

14. The method of claim 11 , further comprising identifying a virtual switch identifier in a packet as a local identifier assigned to the switch, wherein the virtual switch identifier is associated with a virtual switch.

15. The method of claim 11 , further comprising decapsulating a tunnel encapsulation header of the tunnel-encapsulated packet, wherein the tunnel-encapsulated packet is further encapsulated in a second encapsulation header.

16. The method of claim 11 , further comprising operating the switch as a designated forwarder of the gateway subgroup, wherein a designated forwarder forwards a multi-destination packet via edge ports of a switch.

17. The method of claim 11 , further comprising operating the switch as a designated forwarder of a gateway instance, wherein a gateway instance represents a gateway, and wherein a gateway instance includes one or more gateway subgroups.

18. The method of claim 17 , wherein the switch and the remote switch operate as a virtual gateway for the gateway instance, wherein a gateway instance is associated with a virtual gateway.

19. The method of claim 11 , maintaining a membership in a network of interconnected switches, wherein the network of interconnected switches is controlled as a single logical switch.

20. The method of claim 11 , further comprising continuing to decapsulate a tunnel-encapsulated packet in response to determining that the remote switch is unavailable, wherein a tunnel source subnet of the tunnel-encapsulated packet being associated with the gateway subgroup.

21. A non-transitory computer-readable storage medium storing instructions which when executed by a computer cause the computer to perform a method, the method comprising:

operating a switch in conjunction with a remote switch to form a gateway subgroup, wherein the switch and the remote switch actively operate as tunnel gateways;

maintaining a data structure indicating whether a tunnel source subnet is associated with the gateway subgroup;

decapsulating a tunnel-encapsulated packet in response to a tunnel source subnet of the tunnel-encapsulated packet being associated with the gateway subgroup; and

refraining from decapsulating the tunnel-encapsulated packet in response to the tunnel source subnet of the tunnel-encapsulated packet not being associated with the gateway subgroup.

22. The non-transitory computer-readable storage medium of claim 21 , wherein the method further comprises determining an egress port corresponding to a gateway switch, wherein the gateway switch is in a second gateway subgroup associated with the tunnel source subnet of the tunnel-encapsulated packet.

23. The non-transitory computer-readable storage medium of claim 21 , wherein the method further comprises operating the switch as a designated forwarder of the gateway subgroup, wherein a designated forwarder forwards a multi-destination packet via edge ports of a switch.

24. The non-transitory computer-readable storage medium of claim 21 , wherein the method further comprises operating the switch as a designated forwarder of a gateway instance, wherein a gateway instance represents a gateway, and wherein a gateway instance includes one or more gateway subgroups.

25. The non-transitory computer-readable storage medium of claim 21 , wherein the method further comprises continuing to decapsulate a tunnel-encapsulated packet in response to determining that the remote switch is unavailable, wherein a tunnel source subnet of the tunnel-encapsulated packet being associated with the gateway subgroup.