To stack or not to stack?

[Simon Hill]

Looking for thoughts and experiences reference stacking a pair of core/distribution 3750-X switches within a relatively small campus network? Sorry, no budget for 6500s here

I know stacking is the obvious thing to do, especially as the Access switches will be stacked 2960-S switches, but I am a little hesitent. I just like the idea of a standalone pair of core/distribution switches, despite the cleaner design of stacking and easy ability to load balance across uplinks to the Access layer.

Non-stacked 3750-X switches would make core IOS upgrades less disruptive. I experienced strange 3750E stack crashes a few years ago and really don't fancy going through that again - It's one thing losing an Access layer stack, but losing the whole network is something else entirely.

But, am I being over cautious here? Is loosing the whole stack so unlikely now that it's not worth worrying about? Should I be more concerned about STP drawbacks within a non-stacked topology?

[Leo Laohoo]

Non-stacked 3750-X switches would make core IOS upgrades less disruptive. I experienced strange 3750E stack crashes a few years ago and really don't fancy going through that again - It's one thing losing an Access layer stack, but losing the whole network is something else entirely.

Not anymore.  There's a new feature called "Rolling Stock Upgrade".  By automation, the system will load the IOS to each individual appliances in the stack and once that's done, it will reload each member one by one.

Don't bother looking at the 6500E.  I won't delve any further than this.

Kindly compare your 3750X costing with a 4510R+E with Sup7E.  There are cases I've seen where stacking more than 3 3750X, it is better to get a 4500R+E with Sup7E.

[Leo Laohoo]

From your other thread:

Newest code I've experienced it with is 12.2(58)SE1.

Ummmm ... The most "stable" IOS for the 3750E/3750X I've ever used is the 12.2(55)SE5 (aka "55").  Cisco has released (just recently) the rebuild of this code, 12.2(55)SE6 and I'm in the midst of testing this.

If you are going to ask me if I've ever used 12.2(58)SE1 (aka "58") then I will confidently say, yes I have and NO I will not go back to either 12.2(58).SE1, 12.2(58).SE2.   I have also used 15.0(1)SE, SE1 and I'm currently testing the lastest rebuild, 15.0(1)SE3.

[Simon Hill]

Thanks leolaohoo. I will check out the 'Rolling Stock Upgrade' today, which will certainly help. As would a stable IOS.

A pair of 3750-X switches will meet the requirement, so I doubt a 4500E would be competitive, but I'll double check it out. Am I correct in thinking there has been reports of failover issues from one supervisor to another? Just thinking that the potential 3750-X stack crash might just be replaced by another risk factor.

So what would you do? I appreciate there is not 'correct' answer and just no 'pros' and 'cons', but what is your own preference?

[Leo Laohoo]

You're right, there are no "right" or "wrong".

It will depend entirely upon you and your network.  I mean, the biggest gripe I have against the 3750X is the amount of switches in a stack.  My rule-of-thumb is a maximum of 6 switches in a stack, anything higher then get a 4500R+E or break up your stack into two.

3750X has a backplane of 32 Gbps (full duplex) while the 4500R+E with Sup7E has 48 Gbps (full duplex).

In the very near future, end of 2012 to first quarter of 2013, the 4500R+E with Sup7E will be supporting VSS. 

[Simon Hill]

OK, thanks.

Only two 3750-X switches required.

No 10Gig. Around a dozen 1Gbps uplinks, so 32Gbps ring will be plenty.

No budget now, or in the forseeable future, for a pair of 4500E core/distribution switches, so VSS is not an attraction.

A single 4500E will probably be too much anyway, so it's most likely down to stacking or not stacking a pair of 3750-X switches.

[Leo Laohoo]

It'll do then.