Techniques for customizing forwarding decisions via a hardware lookup result

Patent metadata

Field	Value
Publication number	US-9419895-B2
Application number	US-201313871777-A
Country	US
Kind code	B2
Filing date	Apr 26, 2013
Priority date	Feb 25, 2013
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

Techniques for customizing forwarding decisions in a network device via a hardware lookup table result are provided. In one embodiment, a network processor of the network device can perform a lookup into a lookup table based on one or more sections of a received packet. The network processor can then determine, based on the lookup, an entry in the lookup table and retrieve, using a pointer included in the lookup table entry, a mode value from a results table. The mode value can identify an operational flow (e.g., a series of forwarding decisions) to be carried out by the network processor for forwarding the received packet.

First claim

What is claimed is:

1. A method comprising:
performing, by a network processor of a network device, a lookup into a first lookup table based on one or more sections of a received multicast data packet, the received multicast data packet implementing one of a plurality of Protocol Independent Multicast (PIM) types that include PIM Sparse Mode (PIM-SM), PIM Dense Mode (PIM-DM), Bidirectional PIM (PIM-BIDIR), and PIM Source-Specific Multicast (PIM-SSM);
determining, by the network processor based on the lookup into the first lookup table, a first lookup table entry matching the one or more sections of the received multicast data packet;
retrieving, by the network processor based on a pointer included in the first lookup table entry, a mode value from a results table, wherein the mode value identifies an operational flow to be carried out by the network processor for forwarding the received multicast data packet, and wherein the mode value differs based upon the PIM type implemented by the received multicast data packet and a (destination address (DA), source address (SA)) key of the first lookup table, the DA corresponding to one or more multicast group addresses associated with the PIM type; and
forwarding, by the network processor, the received multicast packet in accordance with the operational flow identified by the mode value.

2. The method of claim 1 further comprising:
performing a lookup into a second lookup table based on the SA of the received multicast data packet.

3. The method of claim 2 wherein the lookup into the first lookup table and the lookup into the second lookup table are performed by the network processor in parallel.

4. The method of claim 2 wherein the lookup into the second lookup table is based on a L3D of the received multicast data packet.

5. The method of claim 2 wherein the mode value indicates whether the network processor should evaluate or ignore the outcome of the lookup into the second lookup table.

6. The method of claim 1 wherein the lookup into the first lookup table is further based on a Layer 3 Domain (L3D) of the received multicast data packet.

7. The method of claim 1 wherein the network processor does not classify the received multicast data packet as implementing a particular PIM type prior to performing the lookup into the first lookup table.

8. The method of claim 1 wherein the mode value corresponds to one of six predefined mode values.

9. The method of claim 1 wherein the mode value corresponds to a first mode value of six predefined mode values if:
the PIM type implemented by the received multicast data packet is PIM-SM, PIM-DM, or PIM-SSM; and
the (DA, SA) key of the first lookup table entry corresponds to a (G, S) pair.

10. The method of claim 9 wherein the first mode value indicates that the network processor should validate the received packet via the RPF a Reverse Path Forwarding (RPF) check.

11. The method of claim 9 wherein the first mode value indicates that the network processor should forward the received multicast data packet to an egress port of the network device regardless of whether an RPF check passes or fails.

12. The method of claim 1 wherein the mode value corresponds to a second mode value of six predefined mode values if:
the PIM type implemented by the received multicast data packet is PIM-DM; and
the (DA, SA) key of the first lookup table entry corresponds to a (G, *) pair.

13. The method of claim 12 wherein the second mode value indicates that the network processor should forward the received multicast data packet to an egress port of the network device without validating the received packet via an RPF check.

14. The method of claim 12 wherein the second mode value indicates that the network processor should determine whether a lookup into a second lookup table resulted in a hit or miss, and if the lookup into the second lookup table resulted in a miss, the network processor should send a copy of the received multicast data packet to a management processor of the network device for processing.

15. The method of claim 1 wherein the mode value corresponds to a third mode value of six predefined mode values if:
the PIM type implemented by the received multicast data packet is PIM-DM; and
the (DA, SA) key of the first lookup table entry corresponds to a (G/m, *) pair.

16. The method of claim 15 wherein the third mode value indicates that the network processor should drop the received multicast data packet without validating the received packet via an RPF check.

17. The method of claim 1 wherein the mode value corresponds to a fourth mode value of six predefined mode values if:
the PIM type implemented by the received multicast data packet is PIM-SM or PIM-SSM; and
the (DA, SA) key of the first lookup table entry corresponds to a (G, *) pair.

18. The method of claim 17 wherein the fourth mode value indicates that the network processor should validate the received multicast data packet via an RPF check.

19. The method of claim 17 wherein the fourth mode value indicates that the network processor should forward the received multicast data packet to an egress port of the network device regardless of whether an RPF check passes or fails.

20. The method of claim 17 wherein the fourth mode value indicates that the network processor should:
determine whether a lookup into a second lookup table resulted in a hit or miss;
if the lookup into the second lookup table resulted in a hit, determine whether an RPF check resulted in a pass or fail; and
and if the RPF check resulted in a pass, send a copy of the received multicast data packet to a management processor for processing.

21. The method of claim 1 wherein the mode value corresponds to a fifth mode value of six predefined mode values if:
the PIM type implemented by the received multicast data packet is PIM-SM or PIM-SSM; and
the (DA, SA) key of the first lookup table entry corresponds to a (G/m, *) pair.

22. The method of claim 21 wherein the fifth mode value indicates that the network processor should determine whether a lookup into a second lookup table resulted in a hit or miss, and if the lookup into the second lookup table resulted in a hit, send a copy of the received multicast data packet to a management processor for processing.

23. The method of claim 1 wherein the fifth mode value indicates that the network processor should drop the received multicast data packet without validating the received packet via an RPF check.

24. The method of claim 1 wherein the mode value corresponds to a sixth mode value of six predefined mode values if:
the PIM type implemented by the received multicast data packet is PIM-BIDIR; and
the (DA, SA) key of the first lookup table entry corresponds to a (G, *) pair or a (G/m, *) pair.

25. The method of claim 24 wherein the sixth mode value indicates that the network processor should validate the received multicast data packet via an RPF check.

26. The method of claim 24 wherein the sixth mode value indicates that the network processor should forward the received multicast data packet to an egress port of the network device if an RPF check passes, and drop the received multicast data packet if the RPF check fails.

27. The method of claim 1 wherein the mode value is a user-defined value that identifies a custom operational flow for forwarding the received multicast data packet.

Assignees

• Brocade Comm Systems Inc

Inventors

• Liu Jian
• Yeung Wing-Keung Adam

Classifications

• H04L45/745 Primary

  Address table lookup; Address filtering · CPC title

• H04L45/7452 Primary

  Multiple parallel or consecutive lookup operations (lookup operation involving Bloom filters H04L45/7459) · CPC title

• H04L45/16

  Multipoint routing · CPC title