MLAG Peer Alternate IP: Controlling Which Switch Takes MLAG Ports Down?

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Hi,

MLAG on EXOS allows to configure an alternate IP address for the peer switch, see e.g. How to implement MLAG alternate peer ipaddress. This disables the MLAG ports of one of the two MLAG peers in case of an ISC failure, thus preventing problems caused by the split-brain situation.

How is the switch determined that disables the MLAG ports? Can this be configured, e.g. by setting a priority? Is there a show command available to find out which of the switches is supposed to disable MLAG ports in case of an ISC failure?

Thanks,
Erik
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Erik Auerswald, Embassador

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Posted 1 year ago

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Ron Huygens, Employee

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Hi Erik,

If the ISC is down;
The peer with the lower IP address checks if the peer is reachable via alternate IP, if so;
The peer with the lower IP address disables its MLAG ports
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Karthik Mohandoss, Employee

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Hi Eric,

I found this in Concepts Guide 21.1

Note
The MLAG switch having the lower IP address for the alternate path VLAN disables its ports.
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Thanks!
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Bin, Employee

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