[nsp] High CPU question

Gert Doering gert at greenie.muc.de
Sun Apr 25 13:44:49 EDT 2004


Hi,

On Sun, Apr 25, 2004 at 10:33:32AM -0700, Bryan wrote:
> CPU utilization for five seconds: 25%/24%; one minute: 30%; five minutes:
> 26%
> 
> when it is experiencing problems it show's 66%/66% which indicates that
> the interrupts are causing the high utilization but there is not
> indication that there is anything wrong, according to the troubleshooting
> steps on CCO.

High interrupt load won't be caused by BGP.

> router bgp 1234
>  bgp log-neighbor-changes
>  network 10.0.100.0 mask 255.255.254.0
>  network 10.0.155.0 mask 255.255.255.0
>  network 10.0.188.0 mask 255.255.255.0
>  redistribute connected
>  redistribute static

Huh.  While this is certainly not the cause of the problem, it's still
not something I'd recommend to do.  Try to only get those things into
BGP that you want to have there - not just "get me all stuff, I'll filter
it later".  Just a BCP.

[..]
> static routes for other end loop back poitn to their direct connect
> interfaces and static routes for teh 3 networks they are trying to
> advertise pointed to other loopback for loadbalancing.
> 
> I've turned off all of the processes I can think of and have CEF turned on
> try and speed things up and take some CPE utilization away.

CEF should certainly help.

High interrupt load CPU could be caused by excessive ARPing (do they
have large networks directly connected, with lots of addresses that
are not in use?) or by Accounting (netflow or "IP accounting" in use?).

Overly large and unoptimized ACLs (most frequent hits at the top) could 
also cause high CPU load.

Maybe they just have enormous amounts of traffic on their *other*
interfaces?  5 FastE interfaces is quite a lot for a NPE-225, if some or
all of them run at high utilization.

> I'm pretty much at a loss as to what i could be so any help is greatly
> appreciated.

You could send us the remainder of the configuration (strip out passwords,
of course) - the interface configurations and static routes are the most
interesting parts.

gert
-- 
USENET is *not* the non-clickable part of WWW!
                                                           //www.muc.de/~gert/
Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de


More information about the cisco-nsp mailing list