Specifications

Link Aggregation Control Protocol (LACP)
SecureStack A2 Usage Considerations
3-50 SecureStack A2 Configuration Guide
There are a few cases in which ports will not aggregate:
• An underlying physical port is attached to another port on this same switch (loopback).
• There is no available aggregator for two or more ports with the same LAG ID. This can happen
if there are simply no available aggregators, or if none of the aggregators have a matching admin
key and system priority.
• 802.1x authentication is enabled using the set eapol command (Section 10.3.2.7) and ports that
would otherwise aggregate are not 802.1X authorized.
The LACP implementation on the SecureStack A2 device will allow up to a maximum of four ports
into a LAG. The device with the lowest LAG ID determines which underlying physical ports are
allowed into a LAG based on the ports’ LAG port priority. Ports with the lowest LAG port priority
values are allowed into the LAG and all other speed groupings go into a standby state.
When an existing dynamically created LAG is reduced to one port, the SecureStack A2 removes the
LAG from its VLAN and adds the remaining underlying port to the VLAN. For this reason, you
should ensure that the LAG and all the ports in the LAG are assigned to the egress list of the desired
VLAN. Otherwise, when the LAG is removed, the remaining port may be assigned to the wrong
VLAN. The other option is to enable the singleportlag feature as described in Section 3.5.4.8.
NOTE: To aggregate, underlying physical ports must be running in full duplex mode and must be
of the same operating speed.