Claims
- 1. A method for performing a Reverse Path Forwarding (RPF) check, comprising:
receiving a multicast packet via an interface of a network node; obtaining an expected incoming interface identifier for the multicast packet from one of a plurality of locations including a unicast routing table and a multicast forwarding information table; and comparing the expected incoming interface identifier with an identifier for the interface.
- 2. The method of claim 1, further comprising dropping the multicast packet if the expected incoming interface identifier does not match the identifier for the interface.
- 3. The method of claim 1, further comprising forwarding the multicast packet if the expected incoming interface identifier matches the identifier for the interface.
- 4. The method of claim 1, wherein the multicast packet includes multicast flow information.
- 5. The method of claim 4, wherein the obtaining step comprises performing a lookup on the multicast forwarding information table using the multicast flow information to retrieve a RPF flag value and a first expected incoming interface identifier.
- 6. The method of claim 5, wherein the obtaining step comprises performing a lookup on the unicast routing table using the source address to retrieve a second expected incoming interface identifier.
- 7. The method of claim 6, wherein the obtaining step comprises selecting one of the first expected incoming interface identifier and the second expected incoming interface identifier to be the expected incoming interface identifier according to the RPF flag value.
- 8. The method of claim 5, wherein the RPF flag value is representative of a state of a multicast flow that includes the multicast packet.
- 9. The method of claim 5, wherein the multicast forwarding information table comprises a plurality of entries each including a search field and a result field, wherein the search field comprises a multicast flow identifier, and wherein the result field comprises a RPF flag value.
- 10. A network node capable of multicasting, comprising:
means for receiving a multicast packet via an interface of a network node; means for obtaining an expected incoming interface identifier for the multicast packet from one of a plurality of locations including a unicast routing table and a multicast forwarding information table; and means for comparing the expected incoming interface identifier with an identifier for the interface.
- 11. The network node of claim 10, further comprising means for dropping the multicast packet if the expected incoming interface identifier does not match the identifier for the interface.
- 12. The network node of claim 10, further comprising means for forwarding the multicast packet if the expected incoming interface identifier matches the identifier for the interface.
- 13. The network node of claim 10, wherein the multicast packet includes multicast flow information.
- 14. The network node of claim 13, wherein the obtaining means comprises means for performing a lookup on the multicast forwarding information table using the multicast flow information to retrieve a RPF flag value and a first expected incoming interface identifier.
- 15. The network node of claim 14, wherein the obtaining means comprises means for performing a lookup on the unicast routing table using the source address to retrieve a second expected incoming interface identifier.
- 16. The network node of claim 15, wherein the obtaining means comprises means for selecting one of the first expected incoming interface identifier and the second expected incoming interface identifier to be the expected incoming interface identifier according to the RPF flag value.
- 17. The network node of claim 14, wherein the RPF flag value is representative of a state of a multicast flow that includes the multicast packet.
- 18. The network node of claim 13, wherein the multicast forwarding information table comprises a plurality of entries each including a search field and a result field, wherein the search field comprises a multicast flow identifier, and wherein the result field comprises a RPF flag value.
- 19. A network node capable of multicasting, comprising:
a plurality of interfaces; a first circuit coupled to the interfaces and configured to receive a stream of multicast packets, wherein the first circuit, upon receiving a multicast packet via a first one of the interfaces, obtains an expected incoming interface identifier for the multicast packet from one of a plurality of locations including a unicast routing table and a multicast forwarding information table according to at least in part a state of the stream of multicast packets; and a second circuit coupled to the first circuit and configured to compare the expected incoming interface identifier with an identifier for the first interface.
- 20. The network node of claim 19, wherein the second circuit drops the multicast packet if the expected incoming interface identifier does not match the identifier for the interface.
- 21. The network node of claim 19, wherein the second circuit forwards the multicast packet if the expected incoming interface identifier matches the identifier for the interface.
- 22. The network node of claim 19, wherein the multicast packet includes multicast flow information.
- 23. The network node of claim 22, wherein first circuit performs a lookup on the multicast forwarding information table using the multicast flow information to retrieve a RPF flag value and a first expected incoming interface identifier.
- 24. The network node of claim 23, wherein first circuit performs a lookup on the unicast routing table using the source address to retrieve a second expected incoming interface identifier.
- 25. The network node of claim 24, wherein the first circuit selects one of the first expected incoming interface identifier and the second expected incoming interface identifier to be the expected incoming interface identifier according to the RPF flag value.
- 26. The network node of claim 23, wherein the RPF flag value is representative of a state of the stream of multicast packets.
- 27. The network node of claim 22, wherein the multicast forwarding information table comprises a plurality of entries each including a search field and a result field, wherein the search field comprises a multicast flow identifier, and wherein the result field comprises a RPF flag value.
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is entitled to the benefit of provisional Patent Application Serial No. 60/386,079, filed Jun. 4, 2002, which is hereby incorporated by reference for all purposes.
Provisional Applications (1)
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Number |
Date |
Country |
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60386079 |
Jun 2002 |
US |