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Eaps 4 switch ring w/ MLAG

Eaps 4 switch ring w/ MLAG

New Contributor II

I have a bit of confusion around the configuration of the design on a network we have built.

We have four sites, connected by 2 * 10 gig fibre runs.
2 of the sites (2 and 4) are then connected via their own 2 * 10 gig fibre runs for additional resiliency. These will be used as common / shared eaps ports, allowed with the advanced edge license.
All inter site connectivity is currently configured using LACP
Each site has 2 * X620 10 gig switches with an Advanced core license.
The 2 switches at each site are connected to each other via 4 * 10 gig MLAG with an ISC vlan.
VMANS will be used around the ring as we are supplying transit to a number of smaller ISPs.
No layer 3 services are presented on any switches, nor are any layer 2 routing services.


Stacking between switching at each site is not an option as we are expecting between 20-30 gig to be used on each switch with servers at each location.

Is EAPS/LACP the right option? We need hardware redundancy so plugging all ports into a single switch is not workable.
I can't think of another way of doing it without EAPS and LACP however every solution I can think of ends up with some form of loop.
I was thinking just mapping eaps across the top switch and bottom switch, and not including across the MLAG in effect making them seperate switching platforms however there would likely still be possible loops.

If you have any ideas on this that would be great, we have customers needing this up reasonably urgently but I don't want to put in a solution that's not going to work quite right.


Contributor II
EAPSv2 is the name for EAPS rings where you have 2 nodes with a common link (for all/many) rings. Physical connectivity seems fine to me. Make sure EAPS cannot block an ISC link anywhere, anyhow. So a secondary port of a Master shouldn't be an ISC.

New Contributor II
Thanks for the reply,

I am a little confused. I was not aware there was an EAPSv2. Is this new? I can't find very much on it. Is it different to what I am looking at or is it just the standard eaps now included within Extreme switching? Are you able to provide any further information of eapsv2?

All of my switch stacks utilise MLAG so I don't really have anywhere to place the master port if I need to avoid blocking on an ISC. The only other option I can see is converting once of the stacks into standard stacking using the alternate ports however obviously that comes with a bandwidth reduction. I can then use this as a blocking port.

Should I use the master at site 2 or 4 where the common link resides?

I have verified that the advanced edge license is able to provide a common link. You are correct that this was originally a core only feature, however it seems to have been brought down to advanced edge around same time the X620 was released.

The other option I was thinking of was below:

Site one switch one –> Site two switch one

Site two switch two -> Site 3 Switch two

Site 3 Switch one –> site 4 Switch one

Site 4 Switch two -> Site 1 Switch Two

In other words:


In this, I could potentially move site 2 or site 4 into a stack instead of mlag and use that for blocking ports. What are your thoughts here?

Thanks heaps!

Contributor II

I think an EAPSv2 is a correct approach. Site 2 & Site 4 have that common link between them, as you depicted. I don't remember the license requirement for that, I think it has been changed recently, there was a time when you needed Core license. You should double-check that.

I believe you know you must make sure the ISC cannot be blocked by EAPS, so place your Master Port(s) accordingly.

An other approach would have been VXLAN, but the x620 does not support it.

Without MLAG at each site, you could have used Port Isolation feature to have all NNI links active (but I'm not sure this is widely deployed in the field). But it's not possible with MLAG, and I agree MLAG is important at each Site.