Setting this read-write INTEGER to a channel's ifIndex value removes that channel from an inverse multiplexer group's channel list, provided the channel currently exists in the group; the object always reads back as 1. Admins use it to shrink or reconfigure a bonded WAN group, for example when retiring one of its physical DS1/E1 lines. Writing ctWanMMuxGroupDelChannel with the ifIndex of a failing DS1 line removes it from the group so the remaining channels continue carrying traffic.