AOS-W 6.5.3.x | User Guide Link Aggregation Control Protocol | 157
Chapter 6
Link Aggregation Control Protocol
The AOS-W implementation of Link Aggregation Control Protocol (LACP) is based on the standards specified in
802.3ad. LACP provides standardized means for exchanging information with partner systems, to form a Link
Aggregation Group (LAG). LACP avoids port channel misconfiguration.
Two devices (actor and partner) exchange LACP Data Units (DUs) when forming a LAG. Once multiple ports in
the system have the same actor system ID, actor key, partner system ID, and partner key, they belong to the
same LAG.
The maximum number of supported port-channels is eight. With the introduction of LACP, this number
remains the same. A port-channel group (LAG) is created either statically or dynamically through LACP. This
chapter contains the following topics:
n Understanding LACP Best Practices and Exceptions on page 157
n Configuring LACP on page 158
n LACP Sample Configuration on page 160
For information on configuring LACP on OAW-AP220 Series and OAW-AP270 Series access points, see Link
Aggregation Support on OAW-AP220 Series, OAW-AP270 Series, and OAW-AP320 Series on page 588
Hashing is done using the source IP and destination IP of the received frame if the received frame is a IP
packet. Hashing is done using the source MAC and destination MAC of the received frame if the received frame
is a non-IP packet. This hashing algorithm is common for both IP Frames and non-IP Frames as described
below:
The XOR operation performed on the source and destination addresses bitwise and the AND operation is
performed on the result with the Hash Key size bitwise. Typically, the Hash Key size is 8.
Understanding LACP Best Practices and Exceptions
n LACP is disabled by default.
n LACP depends on periodical Tx/Rx of LACP Data Units (LACPDUs). Any failure is noticed immediately and
that port is removed from the LAG.
n The maximum LAG supported per system is eight groups; each group can be created statically or through
LACP.
n Each LAG can have up to eight member ports.
n The LAG group identification (ID) range is 0–7 for both static (port-channel) and LACP groups.
n When a port is added to a LACP LAG, it inherits the port-channel’s properties such as, VLAN membership,
trunk status, and so on.
n When a port is added to a LACP LAG, the port’s property (like speed) is compared to the existing port
property. If there is a mismatch, the command is rejected.
n The LACP commands cannot be configured on a port that is already a member of a static port-channel.
Similarly, if the group assigned in the command lacp group <number> already contains static port
members, the command is rejected.
n The port uses the group number as its actor admin key.
n All ports use long timeout values (90 seconds) by default.
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