This window appears when you select a port group and click Modify in the EtherChannels window.
Check the In Group box for each interface that you want to add to the group.
Uncheck the In Group box for each interface that you want to remove from the group.
For Catalyst 2950 and 3550 switches, you see a Mode cell for each interface. Click in the cell for a member interface if you want to change its mode. From the drop-down list, you can select:
For Catalyst 2950 and 3550 switches, you see a Priority cell for each interface. Click in the cell for a member interface if you want to enter a different a PAgP priority. The interface with the highest priority transmits PAgP packets.