[c-nsp] back to the Layer3 switch topic...

Mark Kent mark at noc.mainstreet.net
Sat Aug 20 18:23:28 EDT 2005


This post is related to one I made last week, but which didn't
generate any replies.

I've got this scenario: two 7206/npe-g1, two gig-e upstreams, just a
bit more than 200Mbs transit traffic, 700 unique MAC addresses and
20,000 ARP entries.  No layer3 switches.

What are the primary benefits of replacing the top level of Layer2
switches with two Layer3 switches?  I can see that it would off-load
all the host-level crud (vlans, hsrp, filtering) from the 7206/npe-g1,
thereby turning them into real edge routers.   Someone else mentioned
in a related question that an IGP would converge faster than HSRP.
Another benefit I can think of is it keeps LAN traffic off the edge
routers.

Anything else?

And in this exact scenario, which cisco layer3 switch would be the
best fit (i.e., not over- or under-kill)?  I'm thinking maybe the 3750
(WS-C3750G-48TS-E), since it's already been determined that we need 48
10/100/1000 ports in each of the two Layer3 switches.

Thanks,
-mark

P.S.  I found a 2003 Cisco-Product-Quick-Reference-Guide, in PDF
      format, which is pretty handy.  Anyone know where I can get a
      2005 version?  The cisco website allows one to order a paper
      copy, but I don't see where to get an online copy.


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