Setting this object adds a channel, identified by its MIB-II ifIndex value, to the channel list of an Inverse Multiplexer group, but only after that interface has already been assigned an acceptable datalink protocol. An admin uses it during group provisioning to build up the set of physical WAN links that will be bonded together; the object always reads back as 1 regardless of how many channels exist. For example, an admin would set this to the ifIndex of a newly configured E1 interface to fold it into an existing inverse-mux group.