Is it possible to stack more than two X670G2-48x-4q switches using alternate stacking?

[Ken_Applebaum]

Hi,

We currently have two X670G2-48x-4q stacks with two stacking nodes each. They are configured for alternate stacking. Each stack uses all the available stacking ports 1:47, 2:47, 1:48 & 2:48. 

These are our core switches.

I figured out that we cannot use the native stacking ports for stacking when alternate stacking is configured. These are used to MLAG the two switches.

We have come to the point where we need to increase the capacity of these switches.
From what I reading, I don't think it will be possible to add a third X670G2-48x-4q to each of these stacks. 

Can anyone verify that this is indeed the case, or provide a potential solution to add a 3rd switch to each of our core switches?

Thanks,
Ken

[Robert_Zdzieblo]

Hi Ken,

Using IRIS tool I was able to create a 4-slot stack consisting of X670G2-48x-4q units.

All of them were connected via 47, 48 ports only, using SummitStack-V technology.

It could also be a 3-slot stack as well I guess.

So I think you could add any number of X670G2-48x-4q units to your existing stack (not exceeding 8 units per stack) and still having your MLAG setup working. 

REGARDS

Robert

[Chris_H · Accepted solution]

Hello,

Yes, it's possible to stack up to 8 compatible units with EXOS. This also applies to the x670-G2 platform.

If you're using alternate stacking, and a ring-topology, then you're currently using probably the following:

Slot1 port 1:47 to slot2 port 2:48 and slot2 port 2:47 to slot1 port 1:48. 

If you want to add a new stack-member you would have to remove one of those links and then just add the new switch in between. Basically go from slot1 port 1:47 to slot2 port 2:48, then from slot2 2:47 to the new slot3 port 3:48 and lastly close the ring from slot3 3:47 to slot1 port 1:48 again.  The new switch should be prepared first though and made ready to be added to the stack, as well as the configuration on the existing stack needs to be amended to include the new slot. You can find info on how to add a new node to a stack here: https://extreme-networks.my.site.com/ExtrArticleDetail?an=000083355 

In your case obviously the new x670-G2 needs to be configured to use alternate stacking as well first.

The main disadvantage by using alternate stacking is that you're obviously limited to the 10Gb links, whereas native stacking could have a higher bandwidth.

[Ken_Applebaum]

Hi Chris, and thank you for your suggestion. 

Yes, we use both stack ports on both of our cores, 1:47 and 2:48, so we have  20 gig available bandwidth between the two stack members. Not sure we want to decrease that, but we will discuss this among our team.

The solution that may work best for us, rather than increase the number of stacking members for each core, would be to deploy two single x670G2s as two additional cores, and create a ring with all four cores. 

Once again, good solution, and one for us to consider.

Thanks!