Bug #4111
BSSGP SUSPEND ACK with unknown BVCI=0
100%
Description
When a GPRS-attached MS initiates a circuit-switched service (e.g. SS/USSD or SMS), OsmoSGSN logs the following:
DBSSGP NOTICE gprs_bssgp.c:556 BSSGP BVCI=0 Rx BVC STATUS, cause=Unknown BVCI DBSSGP ERROR gprs_bssgp.c:563 BSSGP BVCI=0 Rx STATUS cause=Unknown BVCI missing conditional BVCI IE
As far as I understand, OsmoPCU sends BSSGP SUSPEND (BVCI=0) to OsmoSGSN, and gets BSSGP SUSPEND ACK (BVCI=0) from it. So then OsmoPCU realizes that BVCI=0 is now known for some reason, and sends BSSGP STATUS (BVCI=0) with cause "BVCI unknown (5)".
Please see an attached capture. OsmoSGSN is bound to 127.0.0.10:23000, OsmoPCU is at 127.0.0.1:23000.
Related issues
History
#1 Updated by fixeria about 1 year ago
- Project changed from Cellular Network Infrastructure to OsmoPCU
- Subject changed from GPRS Suspension Request with unknown BVCI to BSSGP SUSPEND ACK with unknown BVCI=0
#2 Updated by laforge about 1 year ago
BVCI=0 is the signaling BVCI, which always exists. This is different from the p-t-p
BVCIs which are explicitly brought up by UNBLOCK procedures and the like.
So claiming that BVCI=0 is unknown is wrong in any case. It is perpetual.
#3 Updated by fixeria 9 months ago
- Status changed from New to Feedback
- Assignee set to fixeria
- % Done changed from 0 to 90
Please see:
https://gerrit.osmocom.org/c/osmo-pcu/+/16006 BSSGP: do not reject SUSPEND ACK / NACK messages
https://gerrit.osmocom.org/c/osmo-pcu/+/16007 BSSGP: properly print BVCI for signalling messages (BVCI=0)
