Change in osmo-bsc[master]: RSL: Wrong CCCH_CONFIG in SI3 causes a lot of MO call setup failed wh...

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Minh-Quang Nguyen gerrit-no-reply at lists.osmocom.org
Wed Oct 30 20:19:27 UTC 2019


Minh-Quang Nguyen has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-bsc/+/15909 )


Change subject: RSL: Wrong CCCH_CONFIG in SI3 causes a lot of MO call setup failed when the BTS configured with none combined CCCH mode.
......................................................................

RSL: Wrong CCCH_CONFIG in SI3 causes a lot of MO call setup failed when the BTS configured with none combined CCCH mode.

Issue:
MO call setup signaling failed when the CCCH is configured in none combined with SDCCH (a dedicated TS is configured for SDCCH). The call setup signaling attempts in all SDCCH sub-channels until the MO call setup failed as shown below:

<0007> ../../../git/src/osmo-bsc/osmo_bsc_sigtran.c:305 Initializing resources for new SIGTRAN connection to MSC: RI=SSN_PC,PC=0.23.1,SSN=BSSAP...
<0007> ../../../git/src/osmo-bsc/osmo_bsc_sigtran.c:351 Opening new SIGTRAN connection (id=1) to MSC: RI=SSN_PC,PC=0.23.1,SSN=BSSAP
<0010> ../../../git/src/osmo-bsc/lchan_fsm.c:80 lchan(0-0-1-SDCCH8-0)[0x1eb888]{WAIT_RLL_RTP_ESTABLISH}: (type=SDCCH) lchan allocation failed in state WAIT_RLL_RTP_ESTABLISH: Timeout
<0007> ../../../git/src/osmo-bsc/osmo_bsc_bssap.c:584 SUBSCR_CONN(conn1)[0x249298]{ACTIVE}: Global Call Ref IE of 0 bytes is too short
<0010> ../../../git/src/osmo-bsc/lchan_fsm.c:80 lchan(0-0-1-SDCCH8-1)[0x1eb9c8]{WAIT_RLL_RTP_ESTABLISH}: (type=SDCCH) lchan allocation failed in state WAIT_RLL_RTP_ESTABLISH: Timeout
<0010> ../../../git/src/osmo-bsc/lchan_fsm.c:80 lchan(0-0-1-SDCCH8-2)[0x246e08]{WAIT_RLL_RTP_ESTABLISH}: (type=SDCCH) lchan allocation failed in state WAIT_RLL_RTP_ESTABLISH: Timeout
<0010> ../../../git/src/osmo-bsc/lchan_fsm.c:80 lchan(0-0-1-SDCCH8-3)[0x246f48]{WAIT_RLL_RTP_ESTABLISH}: (type=SDCCH) lchan allocation failed in state WAIT_RLL_RTP_ESTABLISH: Timeout
<0010> ../../../git/src/osmo-bsc/lchan_fsm.c:80 lchan(0-0-1-SDCCH8-4)[0x247088]{WAIT_RLL_RTP_ESTABLISH}: (type=SDCCH) lchan allocation failed in state WAIT_RLL_RTP_ESTABLISH: Timeout
<0000> ../../../git/src/libosmo-mgcp-client/mgcp_client_fsm.c:526 MGCP_CONN(to-MSC)[0x24a1f8]{ST_READY}: MGW/DLCX: abrupt FSM termination with connections still present, sending unconditional DLCX...
<0000> ../../../git/src/libosmo-mgcp-client/mgcp_client_fsm.c:526 MGCP_CONN(to-BTS)[0x251a58]{ST_READY}: MGW/DLCX: abrupt FSM termination with connections still present, sending unconditional DLCX...
<0010> ../../../git/src/osmo-bsc/abis_rsl.c:2018 lchan(0-0-2-TCH_F-0)[0x2475e0]{WAIT_RF_RELEASE_ACK}: (type=TCH_F) Rx IPACC DLCX IND

After an investigation, it turns out that the BTS broadcasts wrong CCCH_CONF=1, i.e. combined CCCH and SDCCH instead of CCCH_CONF=0, i.e. none combined CCCH.

Fixes:
- The generation of SI3 looks for CCCH information in BTS->C0 timeslots configuration that have never been updated during parsing the BSC configuration file.
- Properly update BTS->C0 timeslots configuration during parsing the BSC configuration file solves the issue.

Change-Id: I33ea7808ac1bd064b88fd609bd7dfe0c8aa341f2
---
M src/osmo-bsc/bsc_vty.c
1 file changed, 4 insertions(+), 0 deletions(-)



  git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/09/15909/1

diff --git a/src/osmo-bsc/bsc_vty.c b/src/osmo-bsc/bsc_vty.c
index a388c9a..6e02e06 100644
--- a/src/osmo-bsc/bsc_vty.c
+++ b/src/osmo-bsc/bsc_vty.c
@@ -4336,6 +4336,10 @@
 
 	ts->pchan_from_config = pchanc;
 
+	/* update BTS->C0 timeslot configuration so that CCCH_CONF in SI3 will be correctly generated */
+	if (ts->trx == ts->trx->bts->c0)
+		ts->trx->bts->c0->ts[ts->nr].pchan_is = pchanc;
+
 	return CMD_SUCCESS;
 }
 

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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: I33ea7808ac1bd064b88fd609bd7dfe0c8aa341f2
Gerrit-Change-Number: 15909
Gerrit-PatchSet: 1
Gerrit-Owner: Minh-Quang Nguyen <minh-quang.nguyen at nutaq.com>
Gerrit-MessageType: newchange
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