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Catalyst 3560 TCAM exhaustion due to number of routes.

Recently the CPU load of a 3560G L3 switch has been increasing, especially since the activation of ipv4-and-ipv6.

The sdm preference had to be adapted accordingly.

As a result the number of IPv4 routes has been restricted resulting in some software routing.

'show platform tcam utilisation' indicates use of 513 directly ipv4 routes out of 4352 possible ones en 1313 indirectly ipv4 routes out of 1472 possible ones.

This indicates exhaustion for the indirectly ipv4 routes.

Is there any way to shift capacity from direct ipv4 to indirect ipv4 routes ?

The options for "sdm prefer xxx" seem fairly limited.

Throughput on the 3560G is not an issue at the moment.

If ipv4-and-ipv6 combination does not scale well in number of routes (several 1000s),

what platform has higher TCAM capacity for routes (mixed ipv4 - ipv6) ?

Do we need to migrate all switches to a chassis-based type of switch (space is limited, so it may not be possible) ?

The network is still expanding, as is the number of routes.

Any suggestions ?

  • WAN Routing and Switching

Catalyst 3560 TCAM exhaustion due to number of routes.

Why do not summarize to reduce the size of the RIB ?

Super Bronze

Re: Catalyst 3560 TCAM exhaustion due to number of routes.


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3560G TCAM resources aren't extremely generous to begin with, and using IPv6 can use up TCAM very quickly.

I recall one of the later 12.2 IOSs (58?) provides an additional IPv6 SDM template.  Unsure it's also available on the original 3560 series too.  If available, however it divides the TCAM, TCAM resource might be still be unsuitable for your needs.

Another approach would be to use whatever route summarization is possible to reduce the number of routes your 3650s need to have.

If you're looking to upgrade, the 3650X can be tight on TCAM too.  Besides chassis solutions you might want to look at the 4900 series.