In many installations it was very well possible to take down entire cell by mobile terminated short message traffic, which is fact that is highly inconsistent w

In many installations it was very well possible to take down entire cell by mobile terminated short message traffic, which is fact that is highly inconsistent with this "idle channel theory". The GSM signaling infrastructure is not especially suited to reordering and queuing of signaling frames. The scarce resource here is time on PCH (MT case) or RACH (MO case, which is more significant as contention there can waste resources even more), actual data transfer transaction is relatively expensive (and not-so well designed), but comparable in resource consumption to initial allocation of used SDCCH. By the way, it's interesting to note that source and destination addresses of SMS can be larger than it's payload.