Link aggregation is a feature that is used to combine a number ofports together to make a single high-bandwidth data pipeline. Theswitch treats all ports in a trunk group as a single port. TheDES-3526/DES-3550 can support 2-8 ports in a trunk group.  Forfurther details on 802.3ad support on the switch, please see yourswitch manual.

IEEE 802.3ad Link Aggregation Control Protocol (LACP) is used tonegotiate a dynamic aggregated link between the switch and anothernetwork device that supports 802.3ad. For this to work, theswitches must comply with LACP to allow negotiation of theaggregated link. Dynamic link aggregation can be negotiated if oneport group is configured to be the "active" group while the otherport group is designated as a "passive" group.

Scenario:

In this configuration, the 2 DES-3526 switches both support802.3ad. Ports 1-4 are configured for LACP link aggregation. SwitchA will have the active LACP port group and the Switch B will havethe passive LACP port group. Once configured, the switches will beable to dynamically negotiate the aggregated link between them. Soif one link fails, the traffic load is redistributed between theremaining links to provide continuous operation.

Warning: The configuration on the switches isbased on factory default settings on the switches.

NOTE: Before starting make sure that there isno connection between the switches. Making the connections betweenthe switches with link aggregation unconfigured will cause aloop.

Switch Configuration

Step 1 Connect to Switch_A's console connectionto access the CLI.

Step 2 Do a factory reset by issuing thefollowing command in the CLI

reset system

Step 3 Once the switch has booted, issue thefollowing commands in the CLI:

create link_aggregation group_id 1 type lacp
config link_aggregation algorithm mac_destination
config link_aggregation group_id 1 master_port 1 ports 1-4 stateenabled
config lacp_port 1-4 mode active
save

Step 4 Repeat Step 1 andStep 2 for Switch_B.

Step 5 Issue the following commands inSwitch_B's CLI:

create link_aggregation group_id 1 type lacp
config link_aggregation algorithm mac_source
config link_aggregation group_id 1 master_port 1 ports 1-4 stateenabled
save

Step 6 Make the connection between Switch_A andSwitch_B using the configured link_aggregation group ports (ports1-4)

Step 7 The aggregated link should now beworking.