Stack 3750's, or link each back to the core?

[gvb]

We have a few wiring closets with multiple 3750's, each with a pair of fiber connections back to a pair of redundant 4500's or 6500's at the core.

Other than ease of management, and using less fiber, is there any reason to implement stacking in these situations?

[lgijssel]

The stack link is also considerably faster than fiber: 32Gig vs 1Gig.

So I think that this is absolutely something to consider when planning the installation.

Regards,

Leo

[cratejockey · Accepted solution]

3750's have one major advantage over the cheaper 3560's. That advantage is the the 32Gbps Stacking backplane. This essentially gives you scalable and responsive Chassis class switches with out the initial cost of a chassis. I cant see why you would purchase this product without planning on using the stacking.

For planning purposes you should ask yourself.

1. Is the majority of my network traffic in the switch fabric or is it between your Core and your edge?

2. If it is between my Core and edge what ways can I expand my bandwidth to accommodate that traffic today, in a year and in 5 years.

Your current non-stacking configuration works well with core to edge communications because it limits your shared bandwidth to 48 ports. However if you have lots of communication that should be happing between switch ports in that closet your putting undo burden on your up links by not stacking.

I hope this helps. Good luck.

[dpopli]

Note that if you stacking cable you won't be able to use HSRP for redundancy

Regards

[bdantzig]

If you stack the 3750 switches, you can use port-channels as uplinks and split them accross units of the stack. If one of the switches fails, your port channel will stay up. The size of the port-channel can then be set according to your need rather than having to have 2 gig ports from each switch for redundancy. I have recently started using 3750G-12S switches as distribution switches for a building. This allows me to connect my edge stack in the closet with a port-channel back to a pair of distribution switches. The distribution switches have layer 3 links to my core 6500s. So far this is working well for us. We have had one of our edge switches crash and all other switches stayed up and users on the other switches kept working without a hitch, just the way it should be.

This setup is much less expensive than using 4500 or 6500 switches and very reliable. Use the 4500 or 6500 if you are running high touch services where the 3750s may prove anemic.