3750 Error Message

[nshoe18]

I upgraded the IOS on a 3750 Stack that consists of 2 3750G-12S and 2 3750G-24PS. After upgrade I am receiving the following message: %PLATFORM_UCAST-4-PREFIX:  One or more, more specific prefixes could not be programmed into TCAM and are being covered by a less specific prefix, and the packets may be software forwarded.

Anyone see this before?

[Giuseppe Larosa · Accepted solution]

Hello Nshoe18,

yes this is a message that tells you that the number of IP routes is higher then the TCAM CEF entries for IP prefixes.

depending on the use of the switch you may want to change the way the TCAM is programmed (SDM template) in order to get more space for IP prefixes.

see

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/configuration/guide/swsdm.html

a reload is needed after a configuration change to be effective.

if you have already a router SDM template you should consider to find a way to reduce IP routes learned by device:

IP route aggregation on upstream route

for OSPF to put it in a totally stub area

Hope to help

Giuseppe