msc {
	hscale="4";
	ms [label="MS"], omsc [label="MSC/VLR"], hlr [label="HLR"], smsc [label="SMSC"];

	hlr <- smsc [label="GSUP MT-ForwardSM-Req (MR=0xFF, DA=IMSI/MSISDN, OA=SMSC, UI, MMS)"];
	hlr box hlr [label="Route based on IMSI/MSISDN"];
	omsc <- hlr [label="GSUP MT-ForwardSM-Req (MR=0xFF, DA=IMSI/MSISDN, OA=SMSC, UI, MMS)"];

	|||;
	... [label="Connection establishment failure"];
	|||;
	omsc -> hlr [label="GSUP MT-ForwardSM-Err (MR, Cause)"];
	hlr -> smsc [label="GSUP MT-ForwardSM-Err (MR, Cause)"];

	|||;
	... [label="Failed delivery"];
	|||;
	ms <-> omsc [label="Establishment, Auth, Ciph, ..."];
	ms <- omsc [label="CP-DATA(RP-DATA(SMS-DELIVER))"];
	ms -> omsc [label="CP-ACK"];
	ms -> omsc [label="CP-DATA(RP-ERROR)"];
	omsc -> hlr [label="GSUP MT-ForwardSM-Err (MR, Cause)"];
	ms <- omsc [label="CP-ACK"];
	hlr -> smsc [label="GSUP MT-ForwardSM-Err (MR, Cause)"];

	|||;
	... [label="Successful delivery"];
	|||;
	ms <-> omsc [label="Establishment, Auth, Ciph, ..."];
	ms <- omsc [label="CP-DATA(RP-DATA(SMS-DELIVER))"];
	ms -> omsc [label="CP-ACK"];
	ms -> omsc [label="CP-DATA(RP-ACK)"];
	omsc -> hlr [label="GSUP MT-ForwardSM-Res (MR)"];
	ms <- omsc [label="CP-ACK"];
	hlr -> smsc [label="GSUP MT-ForwardSM-Res (MR)"];
}