This gauge reports the aggregate port identifier that the neighboring device associates with the far end of this Ethernet link, as discovered by the physical Ethernet endpoint representing one Ethernet-facing port on the fabric interconnect, together with the neighbor device it discovers on the wire. An administrator verifying that a port channel is correctly bundled on both ends compares peerAggrPortId on this PhysEtherEp instance against the local aggrPortId to confirm the two sides agree. For example, a mismatch between aggrPortId and peerAggrPortId on this PhysEtherEp instance would explain why a port channel is not forming correctly with the neighboring switch.