[c-nsp] 4900M vs. 4503 for core

Jeff Bacon bacon at walleyesoftware.com
Wed Jan 27 18:30:38 EST 2010


> > We are a smaller shop (7 access switches including the datacenter)
with
> > 100Mb desktops and a mix of 100/1000 for servers.  Switch-to- switch
trunks
> > are 1Gb.  The number of access switches is very unlikely to change
and we
> > could, in the future move to a 10Gb.  The 4900M solution would save
a
> > non-trivial amount over 4503 with Sup6.

And a cat4948 would be cheaper than either one, while serving the same
purpose. 

> > Is there anything glaringly wrong with choosing the 4900M using
twin-gig
> > based connections to the access layer over the 4503 Sup6 and 46xx
line
> > cards in our situation?

When it comes time that you need 10G, there may/will be other fun
options, and your needs may be totally different anyway. In the
meantime, using a 4900M chassis with twin-gig ports seems like a waste.

> What the 3750Gs - I would pick the "G" over the E/10GB  until you need
10
> GB ... the price will have dropped by then -
> is an clustered switch stack that you can run redundant etherchannels
to ;
> one link to one 3750, one link to the other.

If you can still get 3560G/3750Gs. (Well, you can, used/refurb. I have a
stack of 3560Gs I'll sell you!)

> Save your money until you need [ unless you are going to run 10GB to
10GB
> links where a single client to server connection will exceed 1 GB you
can
> just as easily port channel a bunch of 1 GB links and get almost the
same
> effect.

Agreed. It doesn't sound like you need 10G. If you don't care about
microsecond latency and don't have a lot of gig-connected servers
screaming at each other at wire speed (in which case you might end up in
a situation where two full-bore streams map onto the same gig port),
etherchannel will do you fine. 

You could probably use a pair of 3560Gs for your core and get away with
it, without having to spend any real money. I wouldn't actually stack
the cores - too easy for one to take out the other via the stack
cable... but that's a personal preference. 


The other issue is that cat4948s/4900Ms are in short supply nationwide,
at least according to my supplier (and a quick look at ebay) - they
appear to be going like hotcakes. I actually had to wait a couple weeks
for the 4900M I just ordered, and I'm getting offers on my 4948Es that
are WAY higher than you'd think for used equipment. (On the other hand,
if you need to go with Cisco and want something with < 15usec switching
latency, your choices are fairly limited - cat4k or Nexus - and one of
those is a lot cheaper than the other...) 


If you _need_ to buy now once and for all, then you've got a problem.
But if you don't, don't. 




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