[145186] in North American Network Operators' Group
Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation
daemon@ATHENA.MIT.EDU (Mohacsi Janos)
Fri Sep 30 11:39:49 2011
Date: Fri, 30 Sep 2011 17:38:06 +0200 (CEST)
From: Mohacsi Janos <mohacsi@niif.hu>
To: Nick Hilliard <nick@foobar.org>
In-Reply-To: <4E85DF11.1030905@foobar.org>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Fri, 30 Sep 2011, Nick Hilliard wrote:
> On 30/09/2011 15:45, Christopher Morrow wrote:
>> traceroute could certainly be handled in the fastpath.
>
> which traceroute? icmp? udp? tcp? Traceroute is not a single protocol.
>
>> what is that limit? from a single port? from a single linecard? from a
>> chassis? how about we remove complexity here and just deal with this
>> in the fastpath?
>
> on a pfc3, the mls rate limiters deal with handling all punts from the
> chassis to the RP. It's difficult to handle this in any other way.
>
>> My point in calling this all 'stupid' is that by now we all have been
>> burned by this sort of behavior, vendors have heard from all of us
>> that 'this is really not a good answer', enough is enough please stop
>> doing this.
>
> "This is a Hard Problem". There is a balance to be drawn between hardware
> complexity, cost and lifecycle. In the case of the PFC3, we're talking
> about hardware which was released in 2000 - 11 years ago. The ipv6
> fragment punting problem was fixed in the pfc3c, which was released in
> 2003. I'm aware that cisco is still selling the pfc3b, but they really
> only push the rsp720 for internet stuff (if they're pushing the 6500/7600
> line at all).
They are pushing sup2T - however more for enterprise ip layer (6500
series).
Regards,
Janos Mohacsi
