perfsonar-user - [perfsonar-user] CEF forwarding exceptions on Cisco 65xx

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[perfsonar-user] CEF forwarding exceptions on Cisco 65xx

From: Ernest Johanson <>
To: <>
Subject: [perfsonar-user] CEF forwarding exceptions on Cisco 65xx
Date: Tue, 3 Feb 2015 12:28:43 -0800
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At the recent deep dive, the subject came up regarding CEF fowarding exceptions.

On a Cisco 6500, when the number of routing entries exceeds the available CEF memory space, an exception is generated, which will force some traffic to be process switched. If the routing table is subsequently reduced to free up memory space, the CEF exception is not cleared and process switching will continue. A reboot is required to clear the exception and restore normal hardware forwarding.

To check CEF exception status:

show mls cef exception status

To check available CEF memory allocation:

show mls cef maximum-routes

There are configuration commands to change the allocation between IPv4 and IPv6 routes.

References:

https://supportforums.cisco.com/document/59926/troubleshooting-high-cpu-6500-sup720
http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/63992-6k-high-cpu.html

--
Ernest Johanson
Network Engineer
California Institute of Technology

[perfsonar-user] CEF forwarding exceptions on Cisco 65xx, Ernest Johanson, 02/03/2015
- Re: [perfsonar-user] CEF forwarding exceptions on Cisco 65xx, Eli Dart, 02/03/2015

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[perfsonar-user] CEF forwarding exceptions on Cisco 65xx