nanog mailing list archives

Re: Any 1U - 2U Ethernet switches that can handle 4K VLANs?


From: Jeff Kell <jeff-kell () utc edu>
Date: Sun, 25 Jan 2004 20:05:56 -0500


Will Hargrave wrote:

The 'recommended max' number of SVIs for the 3550 is something low like 8.
There is no limited stated in the datasheet for the 3750 - is anyone
running more than 8 SVIs on a 3750?

We're running 30 SVIs on a 3550-12 (only 10 active at the moment, we're in a transition). It is an aggregation switch that feeds back via L3.

The ACL capability on the 3550 seems a lot more capable but the lack of
unicast RPF is irritating. (More irritating, 'ip verify unicast
reachable-via...'  is accepted but silently does nothing)

Agreed - we had PSIRT look into it and the "solution" is probably going to be removing ip verify from the CLI parser :-( We had another 3550 replace a struggling 2621 and it blew it away.

I'd be very interested to hear what conditions you've found cause
problems for Cat3550s. We're planning to buy quite a few more of this range
(probably 3750-24) to reduce L2 size in our network and for CPE-type
uses.

In a new building deployment we used 4500 Sup-IVs as MDF/IDF anchors and populated the distributions with 3550-48s. Most of the 4500s had one 48 port copper 10/100/1000 blade to supply gig-to-desktop where needed (their ASICs are overloaded 8-to-1 so be careful about placement). The
4500 not only doesn't do uRPF, it doesn't do flow either.

The ACLs/MLS features are nice, supporting input ALCs, 'established' keyword, and logging (unlike, say MLS to a 5500 NFFC). It will not process switch these packets but rather "forks" a copy to the CPU to
log if necessary.

It is very annoying that neither 3550 nor 4500 support uRPF. Does anyone know if the 3750 does?

Jeff


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