Users Guide

226 | Link Aggregation Control Protocol Dell Networking W-Series ArubaOS 6.4.x| User Guide
Configuring LACP
Two LACP configured devices exchange LACPDUs to form a link aggregation group (LAG). A device is
configurable as an active or passive participant. In active mode, the device initiates DUs irrespective of the
partner state; passive mode devices respond only to the incoming DUs sent by the partner device. Hence, to
form a LAG group between two devices, one device must be an active participant. For detailed information on
the LACP commands, see the ArubaOS 6.4.x Command-Line Interface Reference Guide.
In the CLI
LACPDUs exchange their corresponding system identifier/priority along with their port’s key/priority. This
information determines the LAG of a given port. The LAG for a port is selected based on its keys. The port is
placed in that LAG only when its system ID/key and partner's system ID/key matches the other ports in the
LAG (if the group has ports).
1. Enable LACP and configure the per-port specific LACP. The group number range is 0–7.
lacp group <group_number> mode {active | passive}
l Active mode—the interface is in an active negotiating state. LACP runs on any link that is configured to
be in the active state. The port in an active mode also automatically initiates negotiations with other
ports by initiating LACP packets.
l Passive mode—the interface is not in an active negotiating state. LACP runs on any link that is configured
in a passive mode. The port in a passive mode responds to negotiations requests from other ports that
are in an active mode. Ports in passive mode respond to LACP packets.
A port in a passive mode cannot set up a port channel (LAG group) with another port in a passive mode.
2. Set the timeout for the LACP session. The timeout value is the amount of time that a port-channel interface
waits for a LACPDU from the remote system before terminating the LACP session. The default long time-
out value is 90 seconds; short is 3 seconds.
lacp timeout {long | short}
3. Set the port priority.
lacp port-priority <priority_value>
The higher the priority value the lower the priority. The range is 1-65535 and the default is 255.
4. View your LACP configuration.
The port uses the group number +1 as the “actor admin key”. All the ports use the long timeout value (90
seconds) by default.
(host)#show lacp 0 neighbor
Flags: S - Device is requesting Slow LACPDUs
F - Device is requesting fast LACPDUs
A - Device is in active mode P - Device is in passive mode
Partner's information
---------------------
Port Flags Pri OperKey State Num Dev Id
---- ----- ---- ------- ----- ---- ----------------
FE 1/1 SA 1 0x10 0x45 0x5 00:0b:86:51:1e:70
FE 1/2 SA 1 0x10 0x45 0x6 00:0b:86:51:1e:70
When a port in a LAG is misconfigured (the partner device is different than the other ports), or the neighbor
timesout or can not exchange LACPDUs with the partner, the port status is displayed as “DOWN” (see the
following example):
(host)#show lacp 0 internal
Flags: S - Device is requesting Slow LACPDUs