Catalyst 3750G Design Query

Unanswered Question
Oct 14th, 2009

We have 5 Catalyst 6509 as access switches for IP phones. We want to integrate them together.

We are thinking of using 2 number of Catalyst 3750G switches as distribution switches as a Stack.

All Catalyst 6509 switches will be uplink to 3750G stack using copper/UTP cable with 2gig cross ether-channel. Also call manager server will be connected to this 3750G stack.

Based on above scenario , i have following queries.

1.Is Catalyst 3750G stack is good choice for distribution to uplink all Catalyst 6509 ?

2.Will there be any performance issue due to Catalyst 3750G in distribution ?

3.If Catalyst 3750G is ok for this scenario , is it OK to have single distribution ( 2 stack members ) , instead of making them 2 different distribution switches without stack

and having 1 or 2 gig uplink from each Catalyst 6509 switch to each distribution switch ?

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Overall Rating: 4 (2 ratings)
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glen.grant Wed, 10/14/2009 - 03:18

Depends on how heavy the traffic is coming off those 6509's . The 3750's have like 32 gig per second backplane capacity. If you have a lotof traffic you might want to think about something a little more robust like the 4500's series. You should try to get some monitoring statistics for all those switches and see what kind of traffic you are looking at. It's a expensive decision you have to live with if you get something that's not up to the task. It also tends to tick off the higher ups. :-)

satish_zanjurne Wed, 10/14/2009 - 03:45

Hi Glen,

Thanks for the reply that sounds reasonable..

But i want to know whether regardless of traffic Catalyst 3750G is recommended or not by Cisco at this layer with Catalyst 6509 as access switches below ?

Joseph W. Doherty Wed, 10/14/2009 - 04:33

You would need to ask Cisco what they recommend, but likely they would suggest another pair of 6500s.

However, from what you describe a dual stack of 3750Gs might be just fine as well as a pair (although if you use a pair, not stacked, you might consider the 3650G).

As Glen notes, expected resource demand is a consideration since the switch's fabric is "only" 32 Gbps, but there's also its PPS to consider too. Further, in a stack configuration you need to consider that limitation of the ring bandwidth (NB: the 32 Mbps ring is really dual 8 Gbps duplex.) All of these considerations, though, I suspect would not be an issue for what you've described.

Within the 3570 series, the 12 SFP port 3750G-12S offers SDM templates not available in the other models which can be useful in a distribution or core layer role (BTW, if you mix this unit in a stack with other models, you can't use the additional templates.)

One advantage of a stack, you can Etherchannel to different stack members which might avoid some uplink usage issues working with a pair of devices.

[edit]

PS:

If there was a need for additional performance, there are other possible platforms besides the 4500 and 6500 chassis. The 3560-E, 3750-E and 4900 series could be considered too.

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