Authors: Wencheng Lu and Sartaj Sahni, Fellow, IEEE

Conf. : IEEE/ACM Transactions on networking, 2010Presenter : JHAO-YAN JIANDate : 2011/3/15

Low-Power TCAMs for Very Large Forwarding Tables

1

The simplest TCAM solutionThe simplest TCAM solution to packet

forwarding requires one TCAM search and one SRAM access to forward a packet.

The power consumption is that for a TCAM of this size.

2

SUBTREE SPLIT(CoolCAM)

3

POSTORDER SPLIT(CoolCAM)

4

SUBTREE SPLIT

5

SUBTREE SPLIT

6

POSTORDER SPLITThe DTCAM buckets are filled using as

many rounds of feasible tree carving and packing as needed to completely carve out .

In each round, we select the bucket B with the fewest forwarding-table prefixes.

The preorder traversal.

7

POSTORDER SPLIT(SP1)

8

POSTORDER SPLIT(SP2)

9

SIMPLE TCAM WITH WIDE SRAM

10

SIMPLE TCAM WITH WIDE SRAM25 (50) is a rather crude estimate of the number

of instructions needed to process a 72-bit (144-bit) suffix node.

We can make 100 M SRAM accesses per second using a 10-ns SRAM and perform about 20 G instruction per second using a 3.2-GHz dual-core processor.

Therefore, about 200 instructions can be executed in the time it takes to make an SRAM access.

The time to process a 72-bit (144-bit) suffix node is only about 1/8 (1/4) that of an SRAM access.

11

12

13

14

EXPERIMENTAL RESULTS(1)

15

EXPERIMENTAL RESULTS(2)

16

EXPERIMENTAL RESULTS(3)

17

EXPERIMENTAL RESULTS(4)

18

EXPERIMENTAL RESULTS(5)

19

20