Specifications

Overview: Link Aggregation Control Protocol (LACP)
Matrix Series Usage Considerations
Matrix DFE-Gold Series Configuration Guide 3-95
3.5.3 Matrix Series Usage Considerations
In normal usage (and typical implementations) there is no need to modify any of the default LACP
parameters on the Matrix Series device. The default values will result in the maximum number of
aggregations possible. If the switch is placed in a configuration with its peers not running the
protocol, no dynamic link aggregations will be formed and the switch will function normally (that
is, will block redundant paths). For information about building static aggregations, refer to set lacp
static (Section 3.5.4.7).
Each Matrix Series module provides 4 virtual link aggregator ports, which are designated in the CLI
as lag.0.1 through lag.0.4. Once underlying physical ports (i.e.; fe.x.x, or ge.x.x) are associated with
an aggregator port, the resulting aggregation will be represented as one LAG with a lag.x.x port
designation. LACP determines which underlying physical ports are capable of aggregating by
comparing operational keys. Aggregator ports allow only underlying ports with keys matching
theirs to join their LAG.
LACP uses a system priority value to build a LAG ID, which determines aggregation precedence.
If there are two partner devices competing for the same aggregator, LACP compares the LAG IDs
for each grouping of ports. The LAG with the lower LAG ID is given precedence and will be
allowed to use the aggregator.
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, and ports that would otherwise aggregate are not 802.1X
authorized.
The LACP implementation on the Matrix Series 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.
NOTE: Only one LACP system priority can be set on a Matrix Series device, using
either the set lacp asyspri command (Section 3.5.4.4), or the set port lacp command
(Section 3.5.4.13).
NOTE: To aggregate, underlying physical ports must be running in full duplex mode
and must be of the same operating speed.