[c-nsp] TCP Timer 70% CPU

Chris Knipe savage at savage.za.org
Mon Aug 13 03:39:00 EDT 2012

Hi All,

I have a Cisco 3825 with 1GB Ram doing some BGP peering (VERY low
traffic, not even 5mbit/s sustained throughput).  Memory usage is
absolutely fine and sitting at less than 50% utilization, and stable.

The Router's CPU is showing an almost linear increases, and the 'TCP
Timer' process is currently sitting at over 70% CPU load.  Cisco
documentation suggests:
TCP Timer

When the Transmission Control Protocol (TCP) timer process uses a lot
of CPU resources, this indicates that there are too many TCP
connection endpoints. This can happen in data-link switching (DLSw)
environments with many peers, or in other environments where many TCP
sessions are simultaneously opened on the router.

What does this actually mean?  The router does not make any TCP
connections (nor does it receive any - except for the odd telnet to
VTY).  Radius and Syslog is enabled however, but this is sending UDP

What can I look at possibly to determine root cause and fix?


Chris Knipe

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