Neels Hofmeyr | c4628a3 | 2018-12-07 14:47:34 +0100 | [diff] [blame] | 1 | msc { |
| 2 | hscale=2; |
| 3 | bsca [label="BSC-A"], i[label="MSC-I"], a[label="MSC-A"], t[label="MSC-T"], bscb[label="BSC-B"]; |
| 4 | |
| 5 | i note t [label="'MSC-A,I,T' are explained in 3GPP TS 49.008 '4.3 Roles of MSC-A, MSC-I and MSC-T'"]; |
| 6 | i note i [label="I = Internal; the MSC that does BSSMAP to the BSC (may change to a remote MSC-B after HO)"]; |
| 7 | a note a [label="A = first; the MSC that has MM control BSSMAP to the BSC (never changes)"]; |
| 8 | t note t [label="T = transitory; the MSC that a handover is going towards (may be MSC-A for inter-BSC HO, may be a remote MSC-B)"]; |
| 9 | |
| 10 | bsca => i [label="BSSMAP Handover Required"]; |
| 11 | i -> a [label="BSSMAP Handover Required"]; |
| 12 | |
| 13 | a -> t [label="MAP Prepare Handover"]; |
| 14 | t => bscb [label="BSSMAP Handover Request"]; |
| 15 | t <= bscb [label="BSSMAP Handover Request ACK"]; |
| 16 | a <- t [label="MAP Prepare Handover Response"]; |
| 17 | i <- a [label="MAP Prepare Handover Response"]; |
| 18 | bsca <= i [label="BSSMAP Handover Command"]; |
| 19 | |
| 20 | --- [label="MS sends RACH to new cell"]; |
| 21 | |
| 22 | t <= bscb [label="BSSMAP Handover Detected"]; |
| 23 | a <- t [label="MAP Access Signaling Request"]; |
| 24 | |
| 25 | t <= bscb [label="BSSMAP Handover Complete"]; |
| 26 | a <- t [label="MAP Send End Signal"]; |
| 27 | |
| 28 | |
| 29 | a abox a [label="MSC-A accepts the new BSC"]; |
| 30 | i note t [label="previous MSC-I gets dropped, MSC-T becomes the new MSC-I"]; |
| 31 | i abox i [label="discard"]; |
| 32 | t abox t [label="MSC-I"]; |
| 33 | |
| 34 | bsca <= i [label="BSSMAP Clear Command"]; |
| 35 | |
| 36 | } |