Pablo Neira Ayuso wrote:

Hi Andreas,

I'm having some problems while bootstrapping RBS2308 with the existing code. I think it is related to LAPD sequence number checkings:

lapd.c:595 TX: 02 01 02 00 0c 11 01 80 1e 02 27 17 59 06 0 00 00 00 00 00 00 00 00 00 00 00 00 ff e5 04 00 dahdi.c:248 dahdi TX (TS=1): 37 bytes lapd_core.c:1832 msg-len 31 sent 31 left 0 N201 260 t byte 0c lapd.c:345 RX: 02 01 01 04 lapd_core.c:1256 RR received in state LAPD_STATE_MF_EST lapd_core.c:739 ack frame 1 lapd_core.c:216 stop T200 lapd_core.c:208 start T203 lapd_core.c:1780 lapd_send_i() called from line 1294 lapd.c:345 RX: 00 01 02 04 10 1c 1a 02 62 11 1c 11 01 80 lapd_core.c:1463 I received in state LAPD_STATE_MF_EST lapd_core.c:1512 N(S) sequence error: N(S)=1, V(R)=0 ^^^^^^^^^^^^^^ It seems to me that the BSC transmits data while something is still coming from the BTS. Then, BSC's LAPD code silently drops the message (without rejection).

Just a bit later the BSC gets a rejection from BTS's RSL layer.

lapd.c:595 TX: 00 01 09 00 dahdi.c:248 dahdi TX (TS=1): 6 bytes lapd_core.c:224 stop T203 lapd_core.c:208 start T203 lapd_core.c:1780 lapd_send_i() called from line 1538 lapd.c:345 RX: 00 01 00 04 10 1c 1a 02 62 11 1c 11 01 80 lapd_core.c:1463 I received in state LAPD_STATE_MF_EST lapd_core.c:1546 incrementing V(R) to 1 lapd_core.c:224 stop T203 lapd_core.c:208 start T203 lapd_core.c:1555 message in single I frame abis_rsl.c:1128 (bts=0,trx=0) ERROR REPORT CAUSE=0x62(Message Sequence Error)

So the bootstrapping process never ends and the BTS never comes up.

Let me know if you can provide any clue to resolve this issue.

Thanks!

complete log file: http://1984.lsi.us.es/~pablo/osmo-nitb-rbs2308.log hi pablo,

the first sequence error (N(S) sequence error) is caused by a missing frame. in this case the frame 0 is expected, but frame 1 is received. this is normal. the lapd protocol sends a REJ message with the current sequence number, so the bts can repeat from there on. it seems that you have some packet loss. in can see many "HDLC abort" messages from dhadi driver in your debug log. maybe you should check the termination. also check if one of the wires from the bts is not connected.

the message sequence error report from bts is a layer 3 message. i don't know why this message appears. i guess that the bts does not expect the rsl messages yet.

your log file shows that you start two lapd instances with tei 0 (rsl) and one instance with tei (62) oml. i think this is the problem. you must first use oml to start and configure bts, then the bts should establish rsl link itself. at least this is what nokia insite does.

regards,

andreas