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-rw-r--r--doc/lchan-release.msc190
1 files changed, 62 insertions, 128 deletions
diff --git a/doc/lchan-release.msc b/doc/lchan-release.msc
index f75b559c1..017c9cf05 100644
--- a/doc/lchan-release.msc
+++ b/doc/lchan-release.msc
@@ -1,149 +1,83 @@
msc {
hscale=2;
- ms [label="MS"], bts [label="BTS"], bsc[label="BSC"], bsc_gscon[label="BSC conn FSM"];
+ ms [label="MS"], bts [label="BTS"], bsc[label="BSC"], bsc_lchan[label="BSC lchan FSM"],
+ bsc_gscon[label="BSC conn FSM"], msc_[label="MSC"];
ms note bsc_gscon [label="various lchan release scenarios"];
-
- ms rbox bsc_gscon [label="IF BSC releases, from BSSMAP Clear Request"];
- bsc note bsc [label="lchan_release() may be called with sacch_deact=true or false.
- Currently, the only time lchan_release(sacch_deact=true) is invoked is upon BSSMAP Clear
- Command, i.e. when the MSC instructs to stop using an active lchan.
- Some error handling code paths however directly invoke
- rsl_rf_chan_release(error=1, SACCH_DEACTIVATE)."];
-
- ---;
- bsc_gscon note bsc_gscon [label="Rx: BSSMAP Clear Request from MSC"];
- bsc <- bsc_gscon [label="gsm0808_clear()"];
- bsc box bsc [label="lchan_release(sacch_deact=1)"];
- bsc box bsc [label="lchan->state = LCHAN_S_REL_REQ"];
- bsc box bsc [label="_lchan_handle_release(sacch_deact=1)"];
- bsc box bsc [label="rsl_release_sapis_from(start=1)"];
- bts <= bsc [label="RSL Release Request (Local End)..."];
- bts <= bsc [label="...for each SAPI, except link_id=0"];
- ms <= bsc [label="RR Channel Release"];
- ms note bsc [label="There is no ACK for RR Channel Release"];
- bsc box bsc [label="rsl_deact_sacch()"];
- bts <= bsc [label="RSL Deactivate SACCH"];
- bsc abox bsc [label="Start T3109 (net->T3109, t3109_expired())"];
+ ms rbox msc_ [label="MSC releases"];
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_ACTIVE"];
+ bsc_gscon abox bsc_gscon [label="ST_ACTIVE"];
+ bsc_gscon <= msc_ [label="BSSMAP Clear Command"];
+ bsc_gscon abox bsc_gscon [label="ST_CLEARING"];
+ bsc_gscon => msc_ [label="BSSMAP Clear Complete"];
+ bsc_gscon -> bsc_lchan [label="LCHAN_EV_RELEASE"];
+ --- [label="IF SAPIs besides SAPI[0] are active"];
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_WAIT_\nSAPIS_RELEASED\nT3109"];
+ bts <= bsc_lchan [label="RSL Release Request (Local End)..."];
+ bts <= bsc_lchan [label="...for each SAPI, except link_id=0"];
+ ms <= bsc_lchan [label="RR Channel Release"];
+ bts <= bsc_lchan [label="RSL Deactivate SACCH",ID="if appropriate pchan"];
...;
- --- [label="If T3109 expires"];
- bsc box bsc [label="t3109_expired()"];
- bsc box bsc [label="rsl_rf_chan_release(error=1)"];
- bts <= bsc [label="RSL Release Request (Local End)..."];
- bts <= bsc [label="...for each SAPI, except link_id=0"];
- bsc box bsc [label="lchan->state = LCHAN_S_REL_REQ"];
- bts <= bsc [label="RSL RF Channel Release"];
- ---;
+ bts => bsc_lchan [label="RSL Release ACKs"];
+ --- [label="END: SAPIs besides SAPI[0] are active"];
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_WAIT_\nBEFORE_RF_RELEASE\nT3111"];
+ bsc_lchan -> bsc_gscon [label="GSCON_EV_FORGET_LCHAN"];
+ bsc_gscon note bsc_gscon [label="has already forgotten the lchan above."];
...;
- bsc rbox bsc [label="continue in the 'Common' part"];
- --- [label="END: 'BSSMAP Clear Request'"];
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_WAIT_\nRF_RELEASE_ACK\n4s"];
+ bts <= bsc_lchan [label="RSL RF Channel Release"];
...;
+ bts => bsc_lchan [label="RSL RF Channel Release ACK"];
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_UNUSED"];
...;
-
- ms rbox bsc_gscon [label="IF BSC releases, from implicitly unused lchan"];
- bsc note bsc [label="The BSC may release old unused lchans after Handover, or release lchans
- after some error condition."];
- bsc note bsc [label="BSC decides to release an unused lchan"];
- bsc box bsc [label="lchan_release(sacch_deact=0)"];
- bsc box bsc [label="lchan->state = LCHAN_S_REL_REQ"];
- bsc box bsc [label="_lchan_handle_release(sacch_deact=0)"];
- bts <= bsc [label="RSL Release Request (Local End)..."];
- bts <= bsc [label="...for all SAPIs"];
...;
- bts note bsc_gscon [linecolor="red",
- label="There seems to be no timer watching over RSL Release Request!"];
+
+ ms rbox msc_ [label="BSC releases, outside of conn FSM's flow"];
+ bsc -> bsc_lchan [label="LCHAN_EV_RELEASE"];
+ --- [label="IF SAPIs besides SAPI[0] are active"];
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_WAIT_\nSAPIS_RELEASED\nT3109"];
+ bts <= bsc_lchan [label="RSL Release Request (Local End)..."];
+ bts <= bsc_lchan [label="...for each SAPI, except link_id=0"];
+ ms <= bsc_lchan [label="RR Channel Release",ID="if conn is present"];
+ bts <= bsc_lchan [label="RSL Deactivate SACCH",ID="if appropriate pchan"];
...;
- bts => bsc [label="RSL Release Confirm..."];
- bts => bsc [label="...for all SAPIs"];
- bsc rbox bsc [label="continue in the 'Common' part"];
- ---;
+ bts => bsc_lchan [label="RSL Release ACKs"];
+ --- [label="END: SAPIs besides SAPI[0] are active"];
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_WAIT_\nBEFORE_RF_RELEASE\nT3111"];
+ bsc_lchan -> bsc_gscon [label="GSCON_EV_FORGET_LCHAN"];
+ bsc_gscon note bsc_gscon [label="conn FSM notices that its primary lchan is gone"];
+ bsc_gscon => msc_ [label="BSSMAP Clear Request"];
+ bsc_gscon abox bsc_gscon [label="ST_WAIT_CLEAR_CMD"];
...;
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_WAIT_\nRF_RELEASE_ACK\n4s"];
+ bts <= bsc_lchan [label="RSL RF Channel Release"];
...;
-
- ms rbox bsc_gscon [label="IF MS releases"];
- ms => bts [label="DISC"];
- bts => bsc [label="RLL Release Ind..."];
- bts => bsc [label="...for each SAPI"];
- bsc rbox bsc [label="continue in the 'Common' part"];
- ---;
+ bts => bsc_lchan [label="RSL RF Channel Release ACK"];
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_UNUSED"];
...;
+ bsc_gscon <= msc_ [label="BSSMAP Clear Command"];
+ bsc_gscon abox bsc_gscon [label="ST_CLEARING"];
+ bsc_gscon => msc_ [label="BSSMAP Clear Complete"];
...;
- ms rbox bsc_gscon [label="Common"];
- --- [label="for each SAPI (?)"];
- bts => bsc [label="RLL Release Confirm / RLL Release Ind"];
- bsc box bsc [label="abis_rsl_rx_rll()"];
- bsc box bsc [label="mark lchan->sapis[link_id] = LCHAN_SAPI_UNUSED"];
- bsc box bsc [label="rll_indication()"];
- bsc box bsc [label="for each bsc_rll_req matching this link_id:
- disable timer, call cb(BSC_RLLR_IND_REL_IND)"];
- bsc box bsc [label="rsl_handle_release()"];
- --- [label="IF all SAPIs are unused"];
- bsc box bsc [label="Stop T3109"];
- bsc note bsc [label="T3109 was started if the MSC requested the release"];
- bsc abox bsc [label="Start T3111 (net->T3111 value, t3111_expired())"];
- --- [label="END: all SAPIs are unused"];
- bsc -> bsc_gscon [label="GSCON_EV_RLL_REL_IND (only if RLL Release Ind)"];
- --- [label="END: for each SAPI"];
-
...;
- bsc box bsc [label="T3111 expires"];
- bsc box bsc [label="rsl_rf_chan_release()"];
- bsc box bsc [label="Stop T3109"];
- bsc note bsc [label="[If lchan->state is LCHAN_S_REL_ERR, don't do anything]"];
- bsc abox bsc [label="Start lchan->act_timer (4s, lchan_deact_tmr_cb())"];
- bts <= bsc [label="RSL RF Channel Release"];
+ ms rbox msc_ [label="MS releases"];
+ ms => bts [label="DISC"];
+ bts => bsc_lchan [label="RLL Release Ind..."];
+ bts => bsc_lchan [label="...for each SAPI"];
+ bsc_lchan note bsc_lchan [label="The lchan FSM notices when all SAPIs have been released"];
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_WAIT_\nBEFORE_RF_RELEASE\nT3111"];
...;
- --- [label="IF lchan->act_timer expires"];
- bsc box bsc [label="lchan_deact_tmr_cb()"];
- bsc box bsc [label="rsl_lchan_mark_broken(): lchan->state = LCHAN_S_BROKEN"];
- bsc box bsc [label="lchan_free() (see below)"];
- --- [label="END: 'lchan->act_timer expires'"];
+ bsc_lchan abox bsc_lchan [label="LCHAN_ST_WAIT_\nRF_RELEASE_ACK\n4s"];
+ bts <= bsc_lchan [label="RSL RF Channel Release"];
+ bsc_lchan -> bsc_gscon [label="GSCON_EV_FORGET_LCHAN"];
+ bsc_gscon note bsc_gscon [label="conn FSM notices that its primary lchan is gone"];
+ bsc_gscon => msc_ [label="BSSMAP Clear Request"];
+ bsc_gscon abox bsc_gscon [label="ST_WAIT_CLEAR_CMD"];
...;
-
- bts => bsc [label="RSL RF Channel Release ACK"];
- bsc box bsc [label="rsl_rx_rf_chan_rel_ack()"];
- bsc box bsc [label="Stop lchan->act_timer"];
- bsc box bsc [label="Stop T3111"];
-
- --- [label="IF lchan->state == LCHAN_S_BROKEN"];
- bsc note bsc [label="If an ACK comes in late, for specific BTS models, we may choose to 'repair'
- the lchan so that it is usable again, by calling do_lchan_free() directly (see below)."];
- bsc box bsc [label="rsl_rx_rf_chan_rel_ack() exits here and none of below actions happen.
- The lchan remains LCHAN_S_BROKEN indefinitely."];
- --- [label="END: lchan->state == LCHAN_S_BROKEN"];
- bsc box bsc [label="do_lchan_free()"];
- --- [label="IF lchan->state == LCHAN_S_REL_ERR"];
- bsc note bsc [label="If release failed, we take the lchan back into operation after due
- timeout"];
- bsc abox bsc [label="Start lchan->error_timer (T3111+2, error_timeout_cb())"];
- bsc note bsc [label="do_lchan_free() continues, async:"];
+ bts => bsc_lchan [label="RSL RF Channel Release ACK"];
...;
- bsc box bsc [label="error_timeout_cb()"];
- bsc box bsc [label="lchan->state = LCHAN_S_NONE"];
- bsc box bsc [label="dyn TS: activate PDCH..."];
- --- [label="ELSE"];
- bsc box bsc [label="lchan->state = LCHAN_S_NONE"];
- --- [label="END: lchan->state == LCHAN_S_REL_ERR"];
- bsc box bsc [label="lchan_free()"];
- --- [label="IF conn is still associated (and not dyn TS in switchover)"];
- bsc -> bsc [label="S_LCHAN_UNEXPECTED_RELEASE"];
- bsc box bsc [label="handle_release()"];
- bsc box bsc [label="Stop T10"];
- bsc note bsc [linecolor=orange,label="conn->T10 is actually dead code, it is never started.
- Instead, the conn FSM starts ST_WAIT_ASS_COMPL with a T10 value."];
- bsc -> bsc_gscon [label="GSCON_EV_RR_ASS_FAIL"];
- bsc -> bsc_gscon [label="GSCON_EV_TX_SCCP: BSSMAP Clear Request"];
- bsc box bsc [label="bsc_clear_handover()"];
- bsc box bsc [label="Stop T3103"];
- bsc box bsc [label="free handover struct"];
- bsc box bsc [label="lchan->conn = NULL"];
- --- [label="END: 'conn is still associated'"];
- bsc box bsc [label="Stop T3101"];
- bsc note bsc [label="T3101 is started when sending an RR Immediate Assignment"];
- bsc -> bsc [label="S_CHALLOC_FREED"];
- bsc -> bsc [label="rll_lchan_signal()"];
- bsc box bsc [label="for each bsc_rll_req matching this lchan:
- disable timer, call cb(BSC_RLLR_IND_REL_IND)"];
+ bsc_gscon <= msc_ [label="BSSMAP Clear Command"];
+ bsc_gscon => msc_ [label="BSSMAP Clear Complete"];
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-26 11:49:27 +0000