msc {
	hscale=2;
	UE, ENB [label="eNodeB"], BSS, MME, VLR [label="MSC/VLR"], PSTN;

	VLR <= PSTN	[label="ISUP IAM or SIP INVITE"];
	MME <= VLR	[label="SGsAP PAGING REQUEST"];
	ENB <= MME	[label="Paging"];
	UE <= MME	[label="Paging"];

	UE => MME	[label="Extended Service Req"];
	MME => VLR	[label="SGsAP SERVICE REQUEST"];
	ENB <= MME	[label="Initial UE Ctx Setup"];

	UE => BSS	[label="Paging Response"];
	BSS => VLR	[label="COMPL L3 (PAGING RESP)"];
	UE <=> VLR	[label="Normal 2G Voice Call"];
}