LACPDU Transmission on MLAG Ports
To prevent the server node from forming two separate aggregators to the
MLAG peers (which could result in a loop), it is necessary that both MLAG peers transmit LACPDUs
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 LACPUDs on MLAG ports. If the MLAG peers do not communicate with each other, no LACPDUs
are sent out on the MLAG ports. The MLAG peers checkpoint their system MAC and the configured
MAC (if
configured)
to the peer so that the LACP Operational MAC is determined.
- 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 VLAN.
- 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.