11-17-2016 12:43 AM - edited 03-08-2019 08:11 AM
Hello everyone,
I have a little question about an architectural design for the network i'm managing.
Actually, we use two stack of 3*3750-X (using 2*10Gbits/s interconnection) as core, and 4*2960-X as access.
All those switch are in the same room.
So today i'm wondering one thing about this design.
Why not using a stack of 6*3750-X instead of two, since we get everything to do it ?
Since I was not present when the architecture design was developped and installed, i'm not certain my idea is a good one.
Thanks for your help !
Solved! Go to Solution.
11-17-2016 06:21 AM
A couple of possible reasons, some don't believe in running stacks with a large number of stack members. Or, having two independent stacks might improve reliability as you're running two IOS images rather than one (i.e. avoiding a single IOS image being a single point of failure).
If you're doing L2 between the stacks and the access switches, normally I would run a single stack with MEC.
11-17-2016 12:48 AM
Why not using a stack of 6*3750-X instead of two
Co$t.
11-17-2016 12:53 AM
Well since we allready have the switchs, the stacks modules and the cable, there is no cost for me to proceed.
I'm just wondering why the network was designed this way (2 stack).
11-17-2016 06:21 AM
A couple of possible reasons, some don't believe in running stacks with a large number of stack members. Or, having two independent stacks might improve reliability as you're running two IOS images rather than one (i.e. avoiding a single IOS image being a single point of failure).
If you're doing L2 between the stacks and the access switches, normally I would run a single stack with MEC.
11-17-2016 06:35 AM
Thanks Joseph.
Well then i see no reasons to not stack those switchs.
11-17-2016 08:08 AM
Oh, for a 3750X stack, there is another consideration. The 3750X supports PowerStack, but that's limited to 4 stack members (that interconnect their PowerStack cables). If you're using the PowerStack feature, that might also be a reason why six units are running in two stacks.
I recall (?) you can have multiple PowerStack in the same data stack, but if so, I have no experience with such.
11-17-2016 08:13 AM
Outch, then i'll have to take a look then.
Thanks again, i'll let you know when i'll have more informations to provide.
11-17-2016 09:36 AM
Ok, if you're using PowerStack, something that's not well documented with the 3750X, there's an amperage limit to what the PowerStack cables will support. E.g. you cannot load one 3750X with a pair of 1500W PSs, and power an adjacent 3750X PoE ports w/o it having some on-board power on that switch.
Assuming you can have two PowerStacks in the same data stack, you could probably interconnect powered cables, just as they interconnect now. Whether that would be the optimal choice is a different question.
11-17-2016 08:32 AM
So i've just took a look at our physical configration.
We use 6 *3750-X, divided in 2 stack, using StackWyse and Powerstack.
I'm actually reading this article, talking about what you just said on using both Stackwyse and Powerstack :
https://supportforums.cisco.com/document/12575126/how-form-catalyst-3850-data-stack-and-power-stack
I have some research to do, but i think we can do it.
Thanks again for your help Joseph.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide