Change ISC-link between MLAG peers

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Hi everybody.

I'd like to change ISC link between two MLAG peers for some reason. It would be great if someone gave me a few tips about order of work.

I have two x680 switches and LAG between them. It contains four 40G links (VIM4-40G4X-1). This is my ISC link. I'd like to change this LAG to two 10G ports.

I'm a bit confused about it. Especially about order of work.

Should I follow this plan:
1. shutdown four 40G ports
2. delete mlag peer and all other MLAG configuration
3. create new LAG (2x10G). It'll be the future ISC link.
4. create new MLAG peer
5. enable necessary MLAG ports

My simple MLAG configurationcreate mlag peer "xCore2"
configure mlag peer "xCore2" ipaddress vr VR-Default 
enable mlag port 1 peer "xCore2" id 1
enable mlag port 2 peer "xCore2" id 2
enable mlag port 3 peer "xCore2" id 3
enable mlag port 4 peer "xCore2" id 4
enable mlag port 5 peer "xCore2" id 5
enable mlag port 6 peer "xCore2" id 6
enable mlag port 7 peer "xCore2" id 7
enable mlag port 8 peer "xCore2" id 8
enable mlag port 36 peer "xCore2" id 107
enable mlag port 37 peer "xCore2" id 106
enable mlag port 39 peer "xCore2" id 105
enable mlag port 40 peer "xCore2" id 103
enable mlag port 42 peer "xCore2" id 104
enable mlag port 44 peer "xCore2" id 102
enable mlag port 46 peer "xCore2" id 101
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Posted 4 years ago

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Grosjean, Stephane, Employee

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Official Response
You create your new LAG (2x10G) and you add it to the ISC VLAN (without cabling the ports) and you configure the necessary vlans on it too.

The idea will be to unplug the 40G links and plug the 10G links. But for some time, you have no ISC.

If everything is dual-homed :
> If you are running 15.5+, you can configure the alternate health-check path feature to handle automatically this situation.
> or you shut the MLAG port yourself on one MLAG peer.

You remove the 40G links, then plug the 10G links. You remove the 40G LAG from the ISC vlan.

And alternate way to do it, that is not validated by our SQA and *should* work, is to use SRP feature. Once again you create a new LAG for your 10G links, add it to ISC VLAN and add the relevant vlans to it. You configure this port as the backup port fo the 40G LAG in SRP (Software Redundant Port). You plug the 10G links. Once it's ok, you unplug the 40G links.