Route-map modification and TCAM

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Feb 10th, 2010
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Hi all,

does anyone know if in case a route-map, already applied, need to be modified some more actions are needed?

In other words: if I add a clause to an already existing and running route-map, it is immediatly apllied and installed in TCAM or do I need to remove and reapply the global route-map to the interface? Does it generate interruption on the current flows?


We are running IOS 12.2(18)SXE5 on Catalyst 6509


Thanks a lot

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CSCO10235163 Thu, 02/25/2010 - 07:55
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Thanks a lot for the feedback, the doc is really interesting.

In the meanwhile I modified the existing route-map by adding a clause where, on ACL matching, the next-hop is modified.

I verified what happened by the use of command 'sh tcam interface vlanXXX acl in ip' where vlanXXX is the vlan on which route-map is applied. Just in case of interest for others:

- if the next hop to be set is in MSFC arp table at the time of configuration, the acl appears inside TCAM preceeded by 'policy-route'

- if the next hop to be set is NOT in MSFC arp table at the time of configuration, the acl appears inside TCAM preceeded by 'punt' and as I understood it means it will be processed by software; as soon as an icmp is directed to the next hop by populating arp table, 'punt' change in 'policy-route'


No need to remove and reapply route-map to the interface in order to make the change effective.

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