Cellular Network Infrastructure » Radio Access Network » OsmoBSC

I noticed this when testing the new lchan FSM, which actually waits for OML opstart of the timeslot before setting the pchan values.
BSC test TC_ho_int sets up two BTSes, but with the new lchan FSM it always sees BTS 1's timeslots as uninitialized and cannot pick a TCH/F from it.
I also noticed that I get repeated OPSTART ACKs for BTS 0's timeslots.

To verify, I added a debug printf to osmo-bsc

commit c06e6aae716f991399b4dce923509e9ba5d28414
Author: Neels Hofmeyr <neels@hofmeyr.de>
Date:   Fri Jun 15 18:04:30 2018 +0200

    debug printfs

    Change-Id: Id6cf8ca0024ea2e161218f2419b4ade750370ee6

diff --git a/src/osmo-bsc/bts_ipaccess_nanobts.c b/src/osmo-bsc/bts_ipaccess_nanobts.c
index 843f264ae..4006fa76d 100644
--- a/src/osmo-bsc/bts_ipaccess_nanobts.c
+++ b/src/osmo-bsc/bts_ipaccess_nanobts.c
@@ -324,6 +324,9 @@ static void nm_rx_opstart_ack_chan(struct abis_om_fom_hdr *foh)
         return;
     }

+    printf("XXXXXXXXXXXXXX %s %u-%u-%u\n",
+           __func__,
+           ts->trx->bts->nr, ts->trx->nr, ts->nr);
     gsm_ts_check_init(ts);
 }

diff --git a/src/osmo-bsc/osmo_bsc_main.c b/src/osmo-bsc/osmo_bsc_main.c
index 69db32e55..399ce816d 100644
--- a/src/osmo-bsc/osmo_bsc_main.c
+++ b/src/osmo-bsc/osmo_bsc_main.c
@@ -295,6 +295,11 @@ static void bootstrap_rsl(struct gsm_bts_trx *trx)

     for (i = 0; i < ARRAY_SIZE(trx->ts); i++) {
         struct gsm_bts_trx_ts *ts = &trx->ts[i];
+        printf("XXXXXXXXXXXXXX %s %u-%u-%u %u-%u-%u\n",
+               __func__,
+               trx->bts->nr, trx->nr, i,
+               ts->trx->bts->nr, ts->trx->nr, ts->nr);
+
         generate_ma_for_ts(ts);
         gsm_ts_check_init(ts);
     }

When starting up bts 0, I get

XXXXXXXXXXXXXX bootstrap_rsl 0-0-0 0-0-0
XXXXXXXXXXXXXX bootstrap_rsl 0-0-1 0-0-1
XXXXXXXXXXXXXX bootstrap_rsl 0-0-2 0-0-2
XXXXXXXXXXXXXX bootstrap_rsl 0-0-3 0-0-3
XXXXXXXXXXXXXX bootstrap_rsl 0-0-4 0-0-4
XXXXXXXXXXXXXX bootstrap_rsl 0-0-5 0-0-5
XXXXXXXXXXXXXX bootstrap_rsl 0-0-6 0-0-6
XXXXXXXXXXXXXX bootstrap_rsl 0-0-7 0-0-7
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-0
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-1
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-2
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-3
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-4
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-5
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-6
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-7

But then, when I start bts 1 a little later, I get

XXXXXXXXXXXXXX bootstrap_rsl 1-0-0 1-0-0
XXXXXXXXXXXXXX bootstrap_rsl 1-0-1 1-0-1
XXXXXXXXXXXXXX bootstrap_rsl 1-0-2 1-0-2
XXXXXXXXXXXXXX bootstrap_rsl 1-0-3 1-0-3
XXXXXXXXXXXXXX bootstrap_rsl 1-0-4 1-0-4
XXXXXXXXXXXXXX bootstrap_rsl 1-0-5 1-0-5
XXXXXXXXXXXXXX bootstrap_rsl 1-0-6 1-0-6
XXXXXXXXXXXXXX bootstrap_rsl 1-0-7 1-0-7
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-0
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-1
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-2
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-3
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-4
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-5
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-6
XXXXXXXXXXXXXX nm_rx_opstart_ack_chan 0-0-7

i.e. the RSL bootstrap correctly goes to bts 1, while the OML opstarts happen for bts 0 instead.