[nsp] intermitten ping lags on 7500/rsp4/256M

lexus lexus at ince.st
Thu Jun 12 22:47:04 EDT 2003


Jared,

I am using vip2-40s and vip2-50s and they are dcef/cef capable.  I have
turned on dcef on all cards....

Please tell me how to inspect packetsprior to being forwarded to the RE
and be able to generate the icmp responses at linerate back.


Thnx
-ken


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Jared Mauch
Sent: Thursday, June 12, 2003 7:48 PM
To: Dmitri Kalintsev; cisco-nsp at puck.nether.net
Subject: Re: [nsp] intermitten ping lags on 7500/rsp4/256M

On Fri, Jun 13, 2003 at 08:58:57AM +1000, Dmitri Kalintsev wrote:
> You can't "fix" it. ICMP handler is low-priority process in IOS. These
> "delays" are only evident when you try to get ICMP replies from the
router
> itself, but they do not affect the transit traffic.
> 
> On Thu, Jun 12, 2003 at 04:41:23PM -0400, lexus wrote:
> > Chris,
> > 
> > How did you fix yours?
> > 
> > What IOS image are you running?  I am willing to try anything =)
> > 
> > Thanks
> > -ken
> > 
> > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net
> > [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Cisco Geek
> > Rotation
> > Sent: Thursday, June 12, 2003 3:43 PM
> > To: cisco-nsp at puck.nether.net
> > Subject: RE: [nsp] intermitten ping lags on 7500/rsp4/256M
> > 
> > At 02:15 PM 6/12/2003 -0400, you wrote:
> > >Ive seen the same thing.  If you get on the 7500 and do a..
> > >
> > >Router# sho proc cpu | excl 0.00%
> > >
> > >You will probably see BGP updates jumping in when you hit that
600ms
> > >ping.  At least that is my experience.  How to fix it (if you
consider
> > >this broken) is a very good question :)  I'm open to answers.
> > >
> > >-Scotty
> > 
> > 
> > Ditto here, it's caused by BGP on my 7507.

	What you need is the distributed linecards to inspect packets
prior to being forwarded to the RE and be able to generate the icmp
responses at linerate back.  Obviously non-distributed
platforms (3640, 2600, 2500, 7200, or even 7500 w/ older non-dcef
capable cards) will not be able to respond in this fashion, but they
are more likely to not be performing bgp.

	This doesn't seem like a too complicated thing to do.

	- jared

-- 
Jared Mauch  | pgp key available via finger from jared at puck.nether.net
clue++;      | http://puck.nether.net/~jared/  My statements are only
mine.
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