[c-nsp] ipv6 on a sup32?

[Gert Doering]

Hi,

On Mon, Jun 07, 2010 at 12:03:20PM -0700, Christian MacNevin wrote:
> I'm considering whether it's worth going from a 3750 configuration as a low-end site core router to a
> 6504/sup32 config. The key here really being that I want better exposure to ipv6 routing and features
> should we need them.
> 
> Is this realistic? Anybody done it or have any caveats?

Well.  The Sup32 has a big bag of caveats, but so has the 3750.

The Sup32 has a darn slow CPU, so it will take half an eternity (~12 minutes)
to *boot*.  This can be highly frustrating.  Furthermore, if you use it for
"large BGP things" (even within its limits of 256 k TCAM entries), things
can be slow, or overload the CPU (if you have multiple BGP peers and large
updates going on).

When shuffling packets, the Sup32 is limited by the "shared bus" - no
crossbar fabric on it, so you can't use the more powerful cards with
the Sup32.  OTHO the bus is 32gbit/s fast, so that should suffice for
any scenarios where you'd consider a 3750.

Routing-wise, the Sup32 is a "full" router - full BGP, IPv6 forwarded in
hardware, MPLS, netflow support for IPv4 and IPv6 (netflow v9), etc.

It cannot do a few things (netflow with TCP flags, certain IPv6 packets
are routed in software, ...) but all these are things you can't do on a
3750 anyway.

Another nice plus is that the buffers on the Sup32 and on the more
reasonable cat6k interface modules are not as limited as on the 3750
(and 2960) series...

So - from a "what is there today in both boxes", I'd go for 6504+Sup32.


What is sort of hard to guess is how long the Sup32 will continue to
be supported.  Cisco seems to be really hating this piece of hardware - it
was originally planned to be upgradeable with a larger TCAM to hold the
"full 1 million XL routing table" (and still is), but you can't buy it and
it's not supported - so it might no longer work.  OTOH, the Sup2+Fabric
still has no reasonable successor for "mostly layer 2" switching, because
the Sup32 has no fabric (and can't use the S2 fabric), so it's unclear
what its future might be...

gert
-- 
USENET is *not* the non-clickable part of WWW!
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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