[c-nsp] WCCPv2 Cisco 7600 + mask assignment problems

[Dean Smith]

When we had TCAM issues...It would have been L2 Redirect + NetApp caches.
The TCAM was an ACL merge thing - we had outbound ACLs and the redirect
(controlled by ACL) on the same interface. A minor change to an ACL kicked
it all to the MSFC and things got very slow, very quickly. It was a while
back now - and the quickest if not the cheapest - solution was simply to
split the functionality. Hence the WCCP is now on 7200+G1.

We use an ACL to determine some sites/clients that aren't cached. We try to
keep it to a minimum but its easier to let some clients bypass the cache
than spend 2 weeks persuading them that issues accessing www.acme.com are
non-cache related.

This is the current "sh ip wccp web-cache detail" (one of 6 caches). - which
I presume to mean we're Hashed not Masked ?. IOS is 12.3(3). I don't think
we've had to change IOS since deployment on those boxes. I see the command
ref for 12.4 now also shows the process/fast/CEF switched counts.

#sh ip wccp web-cache detail

WCCP Cache-Engine information:
        Web Cache ID:          x.x.x.x
        Protocol Version:      2.0
        State:                 Usable
        Initial Hash Info:     00000000000000000000000000000000
                               00000000000000000000000000000000
        Assigned Hash Info:    00000000000000000000000000000000
                               00000000000000000000000003FFFFFF
        Hash Allotment:        26 (10.15%)
        Packets Redirected:    3861396156
        Connect Time:          7w0d

Dean


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Mark Pace Balzan
Sent: 11 September 2006 20:06
To: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] WCCPv2 Cisco 7600 + mask assignment problems


Dean,


That I know of (but don't have real world production figures in hand) the
max performance will be when wccp negotation between router (6500 in this
case) and cache/s  results in L2 forwarding (or MAC rewrite) for the
redirection and packet return - ie from router to cache, and vice-versa for
packets returned by cache to router, _AND_ MASK for assignment.  You can
find this status from a 'sh ip wccp web-cache detail'  Anything else (ie GRE
redirection and/or HASH assignment) will result in software forwarding on
the MSFC and therefore lower performance.  

Do you recall what wccp combination you had. Also what was the caching
vendor ?  Not all vendors suppport all wccp combinations.

I don't exactly know how each of the wccp combination affects TCAM resource
consumption on the Sup2 and other Cat6k supervisors. Im not exactly the
expert here.....so Lincoln and Tim may possibly fill in on the exact
figures, although there have been a number of posts on the subject.


Cheers


Mark


 
> 
> ------------------------------
> 
> Date: Mon, 11 Sep 2006 19:12:00 +0100
> From: "Dean Smith" <dean at eatworms.org.uk>
> Subject: Re: [c-nsp] WCCPv2 Cisco 7600 + mask assignment problems
> To: <cisco-nsp at puck.nether.net>
> Message-ID: <00cb01c6d5cd$c7798640$01011bac at thor>
> Content-Type: text/plain;	charset="US-ASCII"
> 
> What's the best real world performance seen on a 7600/6500 with WCCP ? 
> We moved away from 6500+Sup2+WCCP when we hit TCAM issues.
> 
> We've maxed out a 7200-G1 with about 500 Mb/s of traffic delivered to 
> clients - That's a 3 legged config. Clients / Caches / Internet.
> 
> We're currently looking at using the ACE to deliver 2.5Gb/s+ of cached 
> traffic.
> 
> We'd be using other ACE features aswell so its no purely for the 
> redirect...but WCCP might save us a bigger throughput licence on the 
> ACE ;-)
> 
> Dean
> 

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