| 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"]; | |
| } |