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msc {
hscale=3;
ms [label="MS/BTS"], bsc_lchan[label="BSC lchan FSM"],
bsc_gscon[label="BSC conn FSM"], bsc_mgcp[label="BSC mgcp FSM"], mgw_msc[label="MGW/MSC"];
ms note mgw_msc [label="lchan allocation sequence for BSSMAP Assignment Request"];
bsc_gscon <= mgw_msc [label="BSSMAP Assignment Request"];
bsc_gscon abox bsc_gscon [label="ST_ASSIGNMENT_\nWAIT_LCHAN"];
bsc_lchan <- bsc_gscon [label="lchan_select_by_chan_mode(chan_mode)"];
|||;
--- [label="IF returned lchan is NULL"];
bsc_gscon => mgw_msc [label="BSSMAP Assignment Failure"];
bsc_gscon abox bsc_gscon [label="ST_ACTIVE"];
---;
|||;
bsc_gscon box bsc_gscon [label="store lchan pointer in conn->lchan_for_assignment"];
bsc_lchan <- bsc_gscon [label="lchan_activate(FOR_ASSIGNMENT)"];
...;
|||;
--- [label="on lchan FSM error or timeout"];
bsc_lchan -> bsc_gscon [label="GSCON_EV_LCHAN_ALLOC_ERROR"];
bsc_gscon box bsc_gscon [label="'forget' all about conn->lchan_for_assignment"];
bsc_gscon => mgw_msc [label="BSSMAP Assignment Failure"];
bsc_gscon abox bsc_gscon [label="ST_ACTIVE"];
--- [label="END: 'on error'"];
...;
...;
--- [label="IF lchan FSM decides that it is an lchan for speech"];
bsc_lchan -> bsc_gscon [label="GSCON_EV_ENSURE_MGW_ENDPOINT"];
--- [label="IF there is an MGW endpoint for the BTS already (conn->user_plane.fi_bts)"];
bsc_gscon -> bsc_lchan [label="LCHAN_EV_MGW_ENDPOINT_AVAILABLE"];
--- [label="ELSE: no MGW endpoint for the BTS side yet"];
bsc_gscon abox bsc_gscon [label="ST_ASSIGNMENT_\nWAIT_CRCX_BTS"];
bsc_gscon box bsc_gscon [label="assignment_created_mgw_endpoint = true"];
bsc_gscon -> bsc_mgcp [label="mgcp_conn_create()"];
bsc_mgcp abox bsc_mgcp [label="ST_CRCX_RESP (MGCP_MGW_TIMEOUT = 4s)"];
bsc_mgcp => mgw_msc [label="CRCX (for BTS)"];
bsc_gscon note bsc_mgcp [label="conn FSM relies on mgcp FSM timeout"];
...;
--- [label="On Timeout"];
bsc_mgcp note bsc_mgcp [label="On timeouit, the MGCP FSM will terminate, emitting the parent_term
event set upon mgcp_conn_create():"];
bsc_mgcp -> bsc_gscon [label="GSCON_EV_MGW_FAIL_BTS"];
bsc_gscon note bsc_gscon [label="GSCON_EV_MGW_FAIL_BTS is handled by the conn FSM allstate
handler. It sets conn->user_plane.fi_bts = NULL."];
bsc_gscon -> bsc_lchan [label="LCHAN_EV_MGW_ENDPOINT_ERROR"];
bsc_lchan note bsc_gscon [label="conn FSM timeout handler exits and relies on the lchan FSM
signalling error, which should actually happen immediately:"];
bsc_gscon <- bsc_lchan [label="GSCON_EV_LCHAN_ALLOC_ERROR"];
bsc_gscon abox bsc_gscon [label="ST_ACTIVE"];
bsc_gscon box bsc_gscon [label="'forget' all about conn->lchan_for_assignment"];
bsc_gscon => mgw_msc [label="BSSMAP Assignment Failure"];
--- [label="END: 'On Timeout'"];
...;
bsc_mgcp <= mgw_msc [label="CRCX OK (for BTS)"];
bsc_mgcp box bsc_mgcp [label="libosmo-mgcp-client fsm_crcx_resp_cb()"];
bsc_mgcp abox bsc_mgcp [label="ST_READY"];
bsc_mgcp -> bsc_gscon [label="GSCON_EV_MGW_CRCX_RESP_BTS"];
bsc_gscon abox bsc_gscon [label="ST_ASSIGNMENT_\nWAIT_LCHAN"];
bsc_gscon -> bsc_lchan [label="LCHAN_EV_MGW_ENDPOINT_AVAILABLE"];
--- [label="END: lchan FSM decides that it is an lchan for speech"];
...;
...;
bsc_lchan -> bsc_gscon [label="GSCON_EV_LCHAN_ACTIVE"];
bsc_gscon abox bsc_gscon [label="ST_ASSIGNMENT_\nWAIT_COMPLETE\nT10, 6s"];
ms <= bsc_gscon [label="RR Assignment"];
...;
--- [label="On Timeout"];
bsc_gscon => mgw_msc [label="BSSMAP Assignment Failure"];
bsc_gscon -> bsc_lchan [label="LCHAN_EV_LCHAN_RELEASE"];
bsc_gscon box bsc_gscon [label="'forget' all about conn->lchan_for_assignment"];
--- [label="IF assignment_created_mgw_endpoint == true"];
bsc_gscon -> bsc_mgcp [label="mgcp_conn_delete()"];
bsc_gscon note bsc_mgcp [label="If the MGW endpoint didn't exist before the Assignment, release
it now. If there was one before this, it is probably still in use by a previous lchan, so
keep it in place."];
bsc_gscon abox bsc_gscon [label="ST_ACTIVE"];
--- [label="END: 'On Timeout'"];
...;
ms => bsc_gscon [label="RR Assignment Complete"];
bsc_gscon -> bsc_lchan [label="OLD lchan: LCHAN_EV_LCHAN_RELEASE"];
bsc_gscon box bsc_gscon [label="conn->lchan = conn->lchan_for_assignment"];
--- [label="IF: chan_mode a speech mode?"];
bsc_gscon abox bsc_gscon [label="ST_WAIT_MDCX_BTS"];
bsc_gscon -> bsc_mgcp [label="mgcp_conn_modify()"];
bsc_mgcp note bsc_mgcp [label="same mgcp FSM as above, for BTS side"];
bsc_mgcp abox bsc_mgcp [label="ST_MDCX_RESP"];
bsc_mgcp => mgw_msc [label="MDCX (for BTS)"];
...;
--- [label="On Timeout"];
bsc_gscon -> bsc_lchan [label="LCHAN_EV_RELEASE"];
bsc_gscon -> bsc_mgcp [label="mgcp_conn_delete()"];
bsc_gscon => mgw_msc [label="BSSMAP Assignment Failure"];
bsc_gscon abox bsc_gscon [label="ST_WAIT_CLEAR_CMD"];
bsc_gscon => mgw_msc [label="BSSMAP Clear Request"];
--- [label="END: 'On Timeout'"];
...;
bsc_mgcp <= mgw_msc [label="MDCX OK"];
bsc_mgcp abox bsc_mgcp [label="ST_READY"];
bsc_mgcp -> bsc_gscon [label="GSCON_EV_MGW_MDCX_RESP_BTS"];
bsc_gscon abox bsc_gscon [label="ST_WAIT_CRCX_MSC"];
bsc_gscon -> bsc_mgcp [label="mgcp_conn_create()"];
bsc_mgcp note bsc_mgcp [label="second mgcp FSM for MSC side"];
bsc_mgcp => mgw_msc [label="CRCX (for MSC)"];
...;
--- [label="On Timeout"];
bsc_gscon -> bsc_lchan [label="LCHAN_EV_RELEASE"];
bsc_gscon -> bsc_mgcp [label="mgcp_conn_delete()"];
bsc_gscon => mgw_msc [label="BSSMAP Assignment Failure"];
bsc_gscon abox bsc_gscon [label="ST_WAIT_CLEAR_CMD"];
bsc_gscon => mgw_msc [label="BSSMAP Clear Request"];
--- [label="END: 'On Timeout'"];
...;
bsc_mgcp <= mgw_msc [label="CRCX OK (for MSC)"];
bsc_gscon <- bsc_mgcp [label="GSCON_EV_MGW_CRCX_RESP_MSC"];
--- [label="END: chan_mode a speech mode?"];
bsc_gscon => mgw_msc [label="BSSMAP Assignment Complete"];
bsc_gscon abox bsc_gscon [label="ST_ACTIVE"];
}
|
