LACPDU Transmission on MLAG Ports
To prevent the server node from forming two separate aggregators to the
peers (which could result in a loop), it is necessary that
both MLAG peers transmit LACP PDUs with the same System Identifier and Actor Key. The following
points discuss how the System Identifier is determined:
- The MLAG peers must communicate at least once with each
other to generate LACP PDUs on MLAG ports. If the MLAG peers do not communicate with each
other, no LACP PDUs are sent out on the MLAG ports. The MLAG peers checkpoint their system MAC
and checkpoint the configured MAC to the peer to determine the LACP Operational MAC.
- If no LACP MAC is configured on the MLAG peers, the LACP Operational MAC
is the MAC address of the MLAG peer that has the highest IP address for ISC control
- If a different LACP MAC address is configured on the MLAG peers, the
configured MAC is not used. In this case, the LACP Operational MAC address is the MAC address
of the MLAG peer that has the highest IP address for ISC control VLAN.
- The configured MAC address is only used when the same MAC is configured
on both the MLAG peers.