Modifications to EtherChannel

Modifications to EtherChannel
EtherChannel has undergone some changes in the last four years on Cisco switches. It used to
be that you had to group the ports together in order to use them in a channel. Ports 1–4 had
to be used together, 5–8 had to be used together, and so on. If you were using only two, then
they had to be the first two ports in the group of four. Of course, they all had to be on the same
blade as well. The first thing an administrator would do when troubleshooting was to make
sure the correct ports were being used.
The restrictions aren’t quite as difficult now, though. For example, CatOS version 5.3 or higher
system enables you to use whatever ports you want to, as long as they are configured the same.
Different devices will also forward frames across the channel in different ways, and some can
be set up to apply rules based on layer 3 or layer 4 headers. The secret to setting up an effective
EtherChannel topology is to understand the limitations of your equipment and software.