Method for increasing layer-3 longest prefix match scale

Patent metadata

Field	Value
Publication number	US-10374952-B2
Application number	US-201715792615-A
Country	US
Kind code	B2
Filing date	Oct 24, 2017
Priority date	Nov 5, 2013
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

Various embodiments are disclosed for increasing Layer-3 LPM (longest prefix match) routing database in a network platform. In some embodiments, chipsets in fabric modules (FMs) can be partitioned into multiple banks. Network traffic can be directed towards a corresponding bank in the FMs by using a LPM table on a line card (LC). Entries in the LPM table on the LC can be programmed either statically or dynamically based upon LPM routes that are dynamically learned.

First claim

What is claimed is:

1. A computer-implemented method, comprising:
partitioning each of two or more fabric modules (FMs) into two or more banks, wherein the partitioning comprises associating at least two chipsets for each of the two or more FMs into different banks selected from among the two or more banks;
programming two or more entries in a longest prefix match (LPM) table of a line card (LC);
programming the two or more banks in each of the two or more FMs based upon the two or more entries in the LPM table; and
routing a received Layer-3 packet to a particular bank in the LPM table of the LC.

2. The computer-implemented method of claim 1 , further comprising:
assigning a virtual module (VM) identifier to one of the two or more banks in one of the two or more FMs; and
assigning the VM identifier to a corresponding bank in another one of the two or more FMs.

3. The computer-implemented method of claim 2 , further comprising:
forwarding the Layer-3 packet among the two or more banks of the two or more FMs based at least upon assigned VM identifiers of the two or more banks in the two or more FMS.

4. The computer-implemented method of claim 1 , further comprising:
programming one of the two or more entries in the LPM table to point to even FMs of the two or more FMs, wherein the even FMs are programmed with even IP addresses; and
programming the other one of the two or more entries in the LPM table to point to odd FMs, wherein the odd FMs are programmed with odd IP addresses.

5. The computer implemented method of claim 1 , further comprising dynamically assigning two or more entries in the LPM table of the line card (LC) at least based upon routes that are dynamically learned at the LC.

6. The computer implemented method of claim 5 , further comprising increasing, based upon participation of the LC in virtual routing and forwarding (VRF) or virtual design and construction (VDC), a number of the routes using a selective download.

7. The computer implemented method of claim 5 , further comprising aggregating, in response to the routes at the LC becoming too granular to fit in the LPM table, aggregating the routes up by 1 bit-level.

8. One or more non-transitory tangible computer readable media that includes code for execution and when executed by a processor operable to perform operations comprising:
partitioning each of two or more fabric modules (FMs) into two or more banks, wherein the partitioning comprises associating at least two chipsets for each of the two or more FMs into different banks selected from among the two or more banks;
programming two or more entries in a longest prefix match (LPM) table of a line card (LC);
programming the two or more banks in each of the two or more FMs based upon the two or more entries in the LPM table; and
routing a received Layer-3 packet to a particular bank in the LPM table of the LC.

9. The media of claim 8 , the operations further comprising:
assigning a virtual module (VM) identifier to one of the two or more banks in one of the two or more FMs; and
assigning the VM identifier to a corresponding bank in another one of the two or more FMs.

10. The media of claim 9 , the operations further comprising:
forwarding the Layer-3 packet among the two or more banks of the two or more FMs based at least upon assigned VM identifiers of the two or more banks in the two or more FMS.

11. The media of claim 8 , the operations further comprising:
programming one of the two or more entries in the LPM table to point to even FMs of the two or more FMs, wherein the even FMs are programmed with even IP addresses; and
programming the other one of the two or more entries in the LPM table to point to odd FMs, wherein the odd FMs are programmed with odd IP addresses.

12. The media of claim 8 , the operations further comprising dynamically assigning two or more entries in the LPM table of the line card (LC) at least based upon routes that are dynamically learned at the LC.

13. The media of claim 12 , the operations increasing, based upon participation of the LC in virtual routing and forwarding (VRF) or virtual design and construction (VDC), a number of the routes using a selective download.

14. The media of claim 12 , the operations further comprising aggregating, in response to the routes at the LC becoming too granular to fit in the LPM table, aggregating the routes up by 1 bit-level.

15. An apparatus, comprising:
a memory element configured to store data,
a processor operable to execute instructions associated with the data to perform operations comprising:
partitioning each of two or more fabric modules (FMs) into two or more banks, wherein the partitioning comprises associating at least two chipsets for each of the two or more FMs into different banks selected from among the two or more banks;
programming two or more entries in a longest prefix match (LPM) table of a line card (LC);
programming the two or more banks in each of the two or more FMs based upon the two or more entries in the LPM table; and
routing a received Layer-3 packet to a particular bank in the LPM table of the LC.

16. The apparatus of claim 15 , the operations further comprising:
assigning a virtual module (VM) identifier to one of the two or more banks in one of the two or more FMs; and
assigning the VM identifier to a corresponding bank in another one of the two or more FMs.

17. The apparatus of claim 16 , the operations further comprising:
forwarding the Layer-3 packet among the two or more banks of the two or more FMs based at least upon assigned VM identifiers of the two or more banks in the two or more FMS.

18. The apparatus of claim 16 , the operations further comprising:
programming one of the two or more entries in the LPM table to point to even FMs of the two or more FMs, wherein the even FMs are programmed with even IP addresses; and
programming the other one of the two or more entries in the LPM table to point to odd FMs, wherein the odd FMs are programmed with odd IP addresses.

19. The apparatus of claim 16 , the operations further comprising dynamically assigning two or more entries in the LPM table of the line card (LC) at least based upon routes that are dynamically learned at the LC.

20. The apparatus of claim 19 , the operations increasing, based upon participation of the LC in virtual routing and forwarding (VRF) or virtual design and construction (VDC), a number of the routes using a selective download.

Assignees

• Cisco Tech Inc

Inventors

• Banerjee Ayan
• Merchant Sameer
• Mellacheruvu Ramana
• Ponnapalli Ramesh V N
• Ramabadran Srinivasan

Classifications

• H04W72/30

  Resource management for broadcast services · CPC title

• H04L51/10

  Multimedia information · CPC title

• H04L47/33

  using forward notification · CPC title

• H04W28/12

  using signalling between network elements · CPC title

• H04L45/748

  using longest matching prefix · CPC title