Alcatel Carrier Internetworking Solutions 8800 User Manual

Troubleshooting Link Aggregation

Troubleshooting a Link Aggregation Failure

OmniSwitch Troubleshooting Guide

page 7-3

The figure above has the following setup:

• Switch A and Switch B connected back to back and Link Aggregation configured.

• Port 7/1 of Switch A is connected to port 7/1 of Switch B.

• Port 7/2 of Switch A is connected to port 7/2 of Switch B.

• VLAN 10 is assigned to this aggregate.

• PC1 connected to Switch A slot/port 1/5.

• PC2 connected to Switch B slot/port 1/5.

First, verify that the ports and aggregates involved are assigned correctly. The CLI command show 
linkagg will confirm that the aggregates are configured and are enabled and up as shown below:

-> show linkagg
Number  Aggregate  SNMP Id   Size Admin State  Oper State     Att/Sel Ports
-------+----------+---------+----+------------+--------------+-------------

2

Dynamic

40000002

8

ENABLED

UP

2

2

3

Static

40000003

2

ENABLED

UP

2

2

The show linkagg command followed by the aggregation number will show the aggregate state, size, 
number of active ports, number of inactive ports, as well as the primary port. (See the sample below.) Note 
also the primary port is the port that spanning tree runs on. It is important to verify that this port is not 
changing regularly as that could cause spanning tree problems.

-> show linkagg 3

SNMP Id                  : 40000003,

Aggregate Number         : 3,
SNMP Descriptor          : Omnichannel Aggregate Number 3 ref 40000003 size 2,
Name                     : ,
Admin State              : ENABLED,
Operational State        : UP,
Aggregate Size           : 2,
Number of Selected Ports : 2,
Number of Reserved Ports : 2,
Number of Attached Ports : 2,
Primary Port             : 7/1

OmniSwitch 7800

OmniSwitch 7800