Connecting 2nd Cabinet in Data Center

[paulgear]

John, what's your reasoning behind two stacks instead of one, and what is the stacking cable you're using with 5500s? The 5500 stacks i've built have just used the standard 2 x 10 Gbps CX4 modules.

[MikeJeezy]

Thanks guys. Sorry for the delay - wasn't subscribed to the thread for some reason. So if I put 2910's in the 2nd cabinet, would my cabling look like this? (attached). I'm showing single port CX4 modules, but there is a dual port module for the 2910's (part J9149A)

[John Gelten]

Mike,

That picture is what I was thinking of. Run some flavour of spanning-tree on the loop.

@Paul

Indeed... the 5500 uses ethernet-interfaces for stacking. I had been working with other models all week, and they were still on mind probably...

My reasoning for not creating one large stack ... first of all, if the switch uses special stacking-cables, those are limited in length. So you have no choice.

But in his case, that is not a valid reason. Even if normal ethernet-cabling can be used, I may often prefer not to extend a stack to 'remote' locations, just because I can. In this case, I think I might actually prefer to create one large stack, since both racks form one server-farm. It's just that I don't use stacking by default just 'because I can'; I think there has to be a valid benefit in it.

An example I definitely don't prefer to use a large stack is when one of the racks would be a backup- or test-network. Or situations where the risk for a split-brain scenario is larger (like when stacking access-switches that are on different floors in a building).

[paulgear]

Hi MikeJeezy,

That's the topology you would use for independent 2910s with a STP loop, and for 5500s in an IRF loop. If you used a combination of those switch models, you'd probably do something different.