other but rather completely separate. And again from the spec, should you expect one or the other on a channel, you must ignore any packets with the wrong LPD. So AFAIK on a CBCH channel if you ever get a LPD=00 it should be ignored and not fed to a LAPDm processor. Same thing for a BTS side LAPDm instance if it receives a LPD=01 it should be ignored.