msc {
	hscale="2";
	ms [label="MS"], bts [label="BTS"], bsc [label="BSC"], cbc [label="CBC"], cbe [label="CBE"];

	cbc <= cbe [label="New message (duration, geographic scope)"];

	cbc box cbc [label="Determine list of BSCs in scope"];
	bsc <= cbc [label="CBSP WRITE-REPLACE"];
	bsc => cbc [label="CBSP WRITE-REPLACE ACK"];

	bsc box bsc [label="Determine list of BTSs in scope"];
	bsc box bsc [label="Schedule with any other SMSCB for give BTSs"];
	bts <= bsc [label="RSL SMSCB COMMAND"];

	ms <= bts [label="CBCH SMSCB block (1/4)"];
	ms <= bts [label="CBCH SMSCB block (2/4)"];
	ms <= bts [label="CBCH SMSCB block (3/4)"];
	ms <= bts [label="CBCH SMSCB block (4/4)"];
	bts box bts [label="BTS doesn't retransmit unless type=default"];

	bts => bsc [label="RSL CBCH LOAD IND"];
	bsc box bsc [label="flow control; scheduling"];
}