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

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 <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
> >_______________________________________________
> >cisco-nsp mailing list  cisco-nsp at puck.nether.net
> >https://puck.nether.net/mailman/listinfo/cisco-nsp
> >archive at http://puck.nether.net/pipermail/cisco-nsp/
>
>
>
> 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
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