Specifications

Link Aggregation Control Protocol (LACP)
Configuring Link Aggregation
3-36 SecureStack B2 Configuration Guide
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 3.5.4.6).
Each SecureStack B2 unit provides six virtual link aggregator ports, which are designated in the
CLI as lag.0.1 through lag.0.6. 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 using the set eapol command (Section 11.3.2.7) and ports that
would otherwise aggregate are not 802.1X authorized.
The LACP implementation on the SecureStack B2 device will allow as many ports as possible 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.
3.5.4 Configuring Link Aggregation
Purpose
To disable and re-enable the Link Aggregation Control Protocol (LACP), to display and configure
LACP settings for one or more aggregator ports, and to display and configure the LACP settings for
underlying physical ports that are potential members of a link aggregation.