[c-nsp] 3750 stack with high CPU from IP Input process.

[VCI Help Desk]

    Ok, but my point is why did the CPU go up at all? The same amount of
traffic was going thru the switch no matter what port that ethernet was
connected. The CPU went from 5% to 50% just because I moved an ethernet
cable. When I moved it back the CPU didn't go down.

      Bill



----- Original Message ----- 
From: Saku Ytti
To: Bill
Cc: cisco-nsp at puck.nether.net
Sent: Sunday, December 25, 2005 2:46 AM
Subject: Re: [c-nsp] 3750 stack with high CPU from IP Input process.


On (2005-12-23 16:02 -0600), Bill wrote:

> Sometimes even higher. I can't figure out why but I did notice that when I
> do a "show interface stats" it shows that all of the interfaces are doing
> "process switching". Fast and CEF switching is enabled on all interfaces
but
> according to the "show interface stats" the stack is doing "process
> switching". I assume this is the reason for the high CPU usage.

 Actually if you see process switching only, you're pretty safe, all
traffic that you handle in CPU should be destined to you, which should
mean process switching. Hardware processed traffic doesn't appear in
the counters you mention.

>     This switch stack has 1 routed interface as the gateway for the entire
> stack. It connects to a 3662 router. And it has 3 VLANs for routing
specific
> networks.

 What SDM profile are you running? How many MAC addresses? How many routes?
Do you have ACL's, if so what do they contain (log statement, lot of
port ranges?).

>     Anyone have any ideas? So far Cisco tech has been no help.

 What IOS are you running? Can you upgrade to 12.2(25)SED1 (if you do,
remember that it's standard MST since SEC or so)

-- 
  ++ytti