eaps and mlag

Hello extreme guys

is it possible to configure a MLAG ISC-Link over protected eaps? Or are there any technical issues?

Thanks a lot for your reply.

14 replies

Userlevel 6
Hello Fed Ex

The thing to remember is that the ISC link can not be on an EAPS blocked port which means that neither switch in the MLAG can be a master with that link as secondary port.

Also you should always make sure that the ISC is in a redundant configuration.

Let me know if that helps or if you have more questions

Userlevel 4
Layer 2 protocols such as EAPS or STP will be configured to not allow the blocking of the ISC.
Slightly related:
I am have a problem Switching a routed vlan on a pair of BD's via EAPS and MLAG
The Shared EAPS port and the ISC are on different boards

My problem is when I add the vlan to all ports (EAPS Shared Port, ISC and MALG port) is causes a loop.
Any comments would be great.
Userlevel 5
Did you add the new VLAN as protected to EAPS as well?
Yes, It's been working in EAPS for a long time on 8 or 9 rings. I'm trying to move away from EAPS and onto MALG, so any new switches will be in a MALG env. Thanks
Userlevel 5
Did you have the same route through MLAG and EAPS? Both are L2 protocols and that can cause the loop. An edge switch should only connected through either EAPS or MLAG on the same links.
Userlevel 6
Good Morning Conor

The thing to remember with MLAG is that traffic received on MLAG peer ports are not sent our other MLAG Peer ports however if traffic comes into the switch from other ports that traffic is sent on. The filtering of broadcast and multicast is done on the MLAG peer ports not on the ISC.

In your case traffic on a VLAN is coming in EAPS ports that are not MLAG peer ports so that traffic is then sent across the ISC and since the other switches EAPS ports are not MLAG peer ports they are sent out causing the loop.

If you are doing EAPS and MLAG ISC use the same ports as long as those ports will not be blocked by EAPS.

Hope that helps
Thanks for Comment;
I am using one or the other MLAG or EAPS.
The only crossover is that the the same VLAN is switched on both my EAPS ring and my Stack (via MLAG)
Thanks Paul
This should work ! The master in the ring is the last edge switch before the 2nd BD
Userlevel 6
The VLAN is the thing that counts. Broadcast comes across the VLAN and will go out any port in that VLAN. So if a broadcast comes across the ring and goes into slot 3, for example, and the ISC is on slot 2 and also has that VLAN the broadcast will go across the ISC and will loop back.

This is out of the concepts guide

However, flood and multicast traffic will traverse the ISC but will be dropped from MLAG peer port transmission by the ISC blocking filter mechanism. The ISC blocking filter matches all Layer 2 traffic received on the ISC and blocks transmission to all MLAG ports that have MLAG peer ports in the active state.

SInce the EAPS ports are not MLAG peer ports the traffic will not be blocked

Does that help?

Userlevel 4
The ISC link should not configured as EAPS secondary port.
OK Guy's . Thanks for all the comments, but I'm starting to get mixed messages.
Can I configure EAPS and MLAG using the same phy ports for the ISC and the Sec EAPS Port ?
Userlevel 6
If the secondary port is on the master then the answer is no as it will block the ISC port for those VLANS. If the secondary port is on a transit node then it wont matter as the secondary port will not be blocked. The Master is the only one that blocks.

I would recommend creating a LAG group between two modules and using that LAG for your ISC and EAPS link ( as long as it is not the secondary port of the master). You do not want the ISC link to go down or be blocked unless of course one of the nodes goes down.

Does that help?

OK, Back on Track !
The the BD's are Transit, and the blocking it done on the edge (Master)
Therefor no blocking will take place between the BD's, which are also the routers.
Thanks again for your help