| Neels Hofmeyr | 3b5de1b | 2018-06-16 16:08:55 +0200 | [diff] [blame] | 1 | msc { |
| 2 | hscale=2; |
| 3 | ms [label="MS/BTS"], lchan[label="BSC lchan FSM"], ho[label="BSC Handover FSM"], |
| 4 | gscon[label="BSC conn FSM"], msc_[label="MSC"]; |
| 5 | |
| 6 | ms note msc_ [label="inter-BSC Handover Incoming"]; |
| 7 | |
| 8 | gscon <= msc_ [label="N-Connect: BSSMAP Handover Request"]; |
| 9 | gscon box gscon [label="bsc_subscr_con_allocate()"]; |
| 10 | gscon abox gscon [label="ST_INIT"]; |
| 11 | gscon -> gscon [label="GSCON_EV_A_CONN_IND"]; |
| 12 | ho <- gscon [label="handover_start_inter_bsc_in()"]; |
| 13 | |
| 14 | ho abox ho [label="allocate\nHO_ST_NOT_STARTED"]; |
| 15 | ho box ho [label="lchan_select_by_chan_mode()"]; |
| 16 | ho abox ho [label="HO_ST_WAIT_\nLCHAN_ACTIVE"]; |
| 17 | lchan <- ho [label="lchan_activate(FOR_HANDOVER)"]; |
| 18 | lchan rbox lchan [label="(most details omitted, see lchan_fsm diagrams)"]; |
| 19 | |
| 20 | ...; |
| 21 | ...; |
| 22 | --- [label="On any error or timeout"]; |
| 23 | ho box ho [label="handover_end(fail)"]; |
| 24 | ho -> gscon [label="GSCON_EV_HANDOVER_END"]; |
| 25 | gscon note msc_ [label="There is no specific BSSMAP Handover Request NACK message."]; |
| 26 | gscon => msc_ [label="BSSMAP Clear Request"]; |
| 27 | gscon abox gscon [label="ST_CLEARING"]; |
| 28 | gscon rbox msc_ [label="the usual disconnect dance"]; |
| 29 | --- [label="END: 'On any error or timeout'"]; |
| 30 | ...; |
| 31 | ...; |
| 32 | |
| 33 | lchan abox lchan [label="LCHAN_ST_WAIT_\nACTIV_ACK"]; |
| 34 | ms <= lchan [label="RSL Chan Activ"]; |
| 35 | ...; |
| 36 | ms => lchan [label="RSL Chan Activ ACK"]; |
| 37 | lchan -> ho [label="HO_EV_LCHAN_ACTIVE"]; |
| 38 | ho abox ho [label="HO_ST_WAIT_\nRR_HO_DETECT"]; |
| 39 | ho => msc_ [label="BSSMAP Handover Request Acknowledge\nwith RR Handover Command"]; |
| 40 | |
| 41 | ...; |
| 42 | |
| 43 | ms => ho [label="RR Handover Detect\nHO_EV_RR_HO_DETECT"]; |
| 44 | ho => msc_ [label="BSSMAP Handover Detect"]; |
| 45 | ho abox ho [label="HO_ST_WAIT_\nRR_HO_COMPLETE"]; |
| 46 | |
| 47 | ...; |
| 48 | lchan note ho [label="The lchan FSM will continue with RSL and RTP while the HO FSM waits. |
| 49 | HO_EV_LCHAN_ESTABLISHED means that both RSL and RTP are established. |
| 50 | Usually, RTP will be done first, and the HO_EV_LCHAN_ESTABLISHED may be |
| 51 | received even before HO_EV_RR_HO_COMPLETE. |
| 52 | ho_fsm_wait_lchan_established_onenter() decides whether to wait or not."]; |
| 53 | ...; |
| 54 | ms => lchan [label="RSL EST IND"]; |
| 55 | lchan -> ho [label="HO_EV_LCHAN_ESTABLISHED",ID="(may come as early as this, or...)"]; |
| 56 | ms => ho [label="RR Handover Complete (from EST IND)\n HO_EV_RR_HO_COMPLETE"]; |
| 57 | ho abox ho [label="HO_ST_WAIT_\nLCHAN_ESTABLISHED"]; |
| 58 | ...; |
| 59 | lchan rbox lchan [label="when lchan FSM is done with setting up RTP"]; |
| 60 | lchan -> ho [label="HO_EV_LCHAN_ESTABLISHED",ID="(...may come only now)"]; |
| 61 | ho abox ho [label="HO_ST_WAIT_\nMGW_ENDPOINT_TO_MSC"]; |
| 62 | ho -> gscon [label="gscon_connect_mgw_to_msc()"]; |
| 63 | ...; |
| 64 | ho <- gscon [label="HO_EV_MSC_MGW_OK"]; |
| 65 | ho box ho [label="handover_end(OK)"]; |
| 66 | ho => msc_ [label="BSSMAP Handover Complete"]; |
| 67 | |
| 68 | ho -> gscon [label="gscon_change_primary_lchan()"]; |
| 69 | lchan <- gscon [label="LCHAN_RTP_EV_ESTABLISHED"]; |
| 70 | ho -> gscon [label="GSCON_EV_HANDOVER_END"]; |
| 71 | gscon abox gscon [label="ST_ACTIVE"]; |
| 72 | ho box ho [label="detach from parent to not fire another meaningless GSCON_EV_HANDOVER_END"]; |
| 73 | ho abox ho [label="terminate"]; |
| 74 | } |