[c-nsp] 12.2(33)SRA is finally out!

[Tim Stevenson]

Yes, that is my understanding, the initial SYN is handled in the 
process path, while the remaining packets are CEF switched in 
software based platforms.

Tim

At 11:09 AM 7/2/2006 -0400,  uttered:
>Tim,
>
>My apologies for straying off topic, but can you explain how central 
>forwarding platforms (7200, ISR, etc) handle mss-adjust ? The SYN 
>packets get handled in the process path, and the rest of the flow hits CEF ?
>
>On 6/27/06, Tim Stevenson 
><<mailto:tstevens at cisco.com>tstevens at cisco.com> wrote:
>The model is that the ACL TCAM is programmed to punt just initial TCP
>SYN packets to the RP CPU so the MSS can be modified as it transits 
>the router.
>
>Yes, this has implications for the CPU utilization in the face of
>heavy SYN traffic - you can configure the ACL bridge input rate
>limiter on PFC3 to rate limit traffic punted due to an ACL bridge
>result (mls rate-limit unicast acl input <rate>), but doing so could
>be a tradeoff between CPU & session establishment time.
>
>Thanks,
>Tim
>
>At 04:27 AM 6/27/2006, Ian Henderson submitted:
> >On Sun, 25 Jun 2006, Asbjorn Hojmark - Lists wrote:
> >
> > > I don't know for sure, but I don't see how it could be. The MSS is a TCP
> > > option, and when it's changed, you have to recalculate headers checksums
> > > etc.
> >
> >That's why I posted the question - it sounded an odd thing to add.
> >
> >Since posting, our Cisco SE has told us that a number of the features in
> >SRA were crossported from the 7200, possibly including CEF based Adjust
> >MSS.
> >
> >--
> >Ian Henderson, CCIE #14721
> >Senior Network Engineer, iiNet Limited
> >_______________________________________________
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>
>Tim Stevenson, <mailto:tstevens at cisco.com>tstevens at cisco.com
>Routing & Switching CCIE #5561
>Technical Marketing Engineer, Catalyst 6500
>Cisco Systems, <http://www.cisco.com>http://www.cisco.com
>IP Phone: 408-526-6759
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Tim Stevenson, tstevens at cisco.com
Routing & Switching CCIE #5561
Technical Marketing Engineer, Catalyst 6500
Cisco Systems, http://www.cisco.com
IP Phone: 408-526-6759
********************************************************
The contents of this message may be *Cisco Confidential*
and are intended for the specified recipients only.