Fast path forwarding of link state advertisements
View Patent ↗A link state advertisement protocol message received from an originating device over an inbound interface is forwarded over the fast path according to a predetermined forwarding scheme. A forwarding state that defines rules for forwarding the link state advertisement protocol message may be installed in a forwarding table, in which case the link state advertisement protocol message is forwarded over the fast path according to the forwarding state. The forwarding state may indicate the preferred inbound interface and/or the outbound interface(s) for forwarding the link state advertisement protocol message over the fast path. The link state advertisement protocol message continues to be processed and forwarded by the control plane as usual for robustness.
1. A method for propagating a link state advertisement protocol message by a network device in a communication network, the network device having a fast path for forwarding protocol messages and a control plane for processing protocol messages, the method comprising:
receiving a link state advertisement protocol message from an originating device over an inbound interface; and
forwarding the link state advertisement protocol message by the fast path according to a predetermined forwarding scheme independently of any control plane processing of the link state advertisement protocol message.
2. The method of claim 1 , wherein forwarding the link state advertisement protocol message by the fast path according to the predetermined forwarding scheme comprises:
deciding to forward the link state advertisement protocol message by the fast path;
and determining outbound interface(s) for forwarding the link state advertisement protocol message; and
forwarding the link state advertisement protocol message by the fast path over the outbound interface(s).
3. The method of claim 2 , wherein deciding to forward the link state advertisement protocol message by the fast path comprises:
determining that the inbound interface is a preferred inbound interface for the originating device.
4. The method of claim 1 , wherein forwarding the link state advertisement protocol message by the fast path comprises:
forwarding the link state advertisement protocol message to all interfaces other than the inbound interface.
5. The method of claim 1 , wherein forwarding the link state advertisement protocol message by the fast path comprises:
forwarding the link state advertisement protocol message by the fast path according to a multicast distribution scheme.
6. The method of claim 1 , wherein maintaining the forwarding state for the link state advertisement protocol message comprises:
determining rules for forwarding the link state advertisement protocol message; and
installing a forwarding state in the forwarding table indicating the rules for forwarding the link state advertisement protocol message.
7. The method of claim 1 , further comprising:
routing the link state advertisement protocol message to the control plane; and
processing the link state advertisement protocol message by the control plane.
8. The method of claim 7 , further comprising:
forwarding the link state advertisement protocol message by the control plane.
9. A device for propagating a link state advertisement protocol message in a communication network, the device comprising:
a plurality of interfaces;
a control plane for processing protocol messages; and
a fast path coupled to the control plane and to the plurality of interfaces, the fast path comprising:
receiving logic operably coupled to receive a link state advertisement protocol message from an originating device over an inbound interface; and
fast path forwarding logic responsive to the receiving logic and operably coupled to forward the link state advertisement protocol message according to a predetermined forwarding scheme independently of any control plane processing of the link state advertisement protocol message.
10. The device of claim 9 , wherein the fast path forwarding logic comprises:
forwarding decision logic operably coupled to decide whether to forward the link state advertisement protocol message.
11. The device of claim 10 , wherein the forwarding decision logic is operably coupled to determine whether the inbound interface is a preferred inbound interface for the originating device.
12. The device of claim 9 , wherein the fast path forwarding logic comprises:
outbound interface determination logic operably coupled to determine outbound interface(s) for forwarding the link state advertisement protocol message.
13. The device of claim 9 , wherein the fast path forwarding logic is operably coupled to forward the link state advertisement protocol message to all interfaces other than the inbound interface.
14. The device of claim 9 , wherein the fast path forwarding logic is operably coupled to forward the link state advertisement protocol message according to a multicast distribution scheme.
15. The device of claim 9 , wherein the link state advertisement protocol message is an individually-addressed link state advertisement protocol message, and wherein the fast path forwarding logic is operably coupled to forward the link state advertisement protocol message according to unicast routes.
16. The device of claim 9 , further comprising a forwarding table having at least one forwarding state for the link state advertisement protocol message.
17. The device of claim 16 , wherein the fast path forwarding logic is operably coupled to forward the link state advertisement protocol message according to said forwarding state.
18. The device of claim 9 , wherein the fast path forwarding logic is operably coupled to route the link state advertisement protocol message to the control plane for local processing of the link state advertisement protocol message.
19. The device of claim 18 , wherein the control plane is operably coupled to forward the link state advertisement protocol message via the fast path.
20. A program product comprising a computer readable medium having embodied therein a computer program for propagating a link state advertisement protocol message by a network device in a communication network, the network device having a plurality of interfaces, a control plane for processing protocol message, and a fast path for forwarding protocol messages, the computer program comprising:
receiving logic programmed to receive a link state advertisement protocol message from an originating device over an inbound interface; and
fast path forwarding logic responsive to the receiving logic and programmed to forward the link state advertisement protocol message according to a predetermined forwarding scheme independently of any control plane processing of the link state advertisement protocol message.
21. The program product of claim 20 , wherein the fast path forwarding logic comprises:
forwarding decision logic programmed to decide whether to forward the link state advertisement protocol message.
22. The program product of claim 21 , wherein the forwarding decision logic is programmed to determine whether the inbound interface is a preferred inbound interface for the originating device.
23. The program product of claim 20 , wherein the fast path forwarding logic comprises:
outbound interface determination logic programmed to determine outbound interface(s) for forwarding the link state advertisement protocol message.
24. The program product of claim 20 , wherein the fast path forwarding logic is programmed to forward the link state advertisement protocol message to all interfaces other than the inbound interface.
25. The program product of claim 20 , wherein the fast path forwarding logic is programmed to forward the link state advertisement protocol message according to a multicast distribution scheme.
26. The program product of claim 20 , wherein the fast path forwarding logic is programmed to route the link state advertisement protocol message to the control plane for local processing of the link state advertisement protocol message.