3Com Switch 8800 Family Configuration Guide

110 CHAPTER 14: LINK AGGREGATION CONFIGURATION
[3Com-Ethernet2/1/2] interface ethernet2/1/3
[3Com-Ethernet2/1/3] lacp enable
You must set basic configuration, rate and duplex attribute consistent at both
ends to aggregate successfully the LACP-enabled ports into a dynamic
aggregation group and achieve load sharing.