Link Aggregation Overview; Implementing Aggregate Links - Symbol ES3000 Manual

7-2 ES3000 Advanced Concept Guide

7.1 Link Aggregation Overview

Link aggregation allows the ES3000 switch to bundle individual physical links into a single logical
link, called a link aggregation group, or group. Link aggregation provides increased bandwidth and
creates redundant links between linked devices (partners). It also provides load balancing, where
processing and communication are distributed across links within a group so that no single link is
overwhelmed.
Link aggregation on the ES3000 switch can create logical links either between switches or between
switches and servers or routers that are also configured for link aggregation.
The standard for link aggregation is IEEE 802.3ad. This standard also provides for a dynamic signalling
protocol, the Link Aggregation Control Protocol (LACP). LACP allows linked devices to dynamically
configure and maintain link aggregation groups. The ES3000 switch uses LACP to establish 802.3ad
compliant link aggregation groups.

7.2 Implementing Aggregate Links

The ES3000 switch allows the administrator to create link aggregation groups that include up to eight
physical ports in a single logical link. The administrator can define a maximum of six link aggregation
groups. Each port can participate only in one link aggregation group.
The ports within a link aggregation group must of the same type, either 100BaseT or gigabit. The
switch prevents groups that include both 100BaseT and gigabit ports. When the administrator creates
a link aggregation group, the switch forces all ports within a group to full duplex mode at the highest
speed allowed for the port.
All ports in a group must belong to the same set of VLANs. For example, if port 4 belongs to VLANs
1, 3, and 14, and port 5 belongs to VLANs 1 and 14, the switch does not allow the creation of a link
aggregate group including both ports 4 and 5.
To avoid broadcast storms or loops in the network when configuring a
link aggregation group, disable or disconnect the ports before adding
or removing them from a group. The ports can be re-enabled or
connected after the group is defined.