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Bug #4645

OM2K: "Sequence Error" due to too early iniitialization of RSL during BTS start

Added by laforge 4 months ago. Updated 4 months ago.

Status:
New
Priority:
Normal
Assignee:
Category:
Ericsson BTS
Target version:
-
Start date:
07/03/2020
Due date:
% Done:

10%

Spec Reference:

Description

at least on a RBS2380 I see:

<0004> abis_om2000.c:2898 Rx MO=IS/00/ff/00 Operational Information Accept (80 80 00 06 00 76 05 00 ff 00 )
<0004> abis_om2000.c:2086 OM2000-MO(0-IS-00-ff-00)[0x6120000e3020]{WAIT-OPINFO-ACCEPT}: Received Event RX-OPINFO-ACCEPT
<0004> abis_om2000.c:1864 OM2000-MO(0-IS-00-ff-00)[0x6120000e3020]{WAIT-OPINFO-ACCEPT}: state_chg to DONE
<0004> abis_om2000.c:1871 OM2000-MO(0-IS-00-ff-00)[0x6120000e3020]{DONE}: Terminating (cause = OSMO_FSM_TERM_REGULAR)
<0004> abis_om2000.c:1871 OM2000-MO(0-IS-00-ff-00)[0x6120000e3020]{DONE}: Removing from parent OM2000-BTS(0)[0x612000010120]
<0004> abis_om2000.c:1871 OM2000-MO(0-IS-00-ff-00)[0x6120000e3020]{DONE}: Freeing instance
<0004> fsm.c:573 OM2000-MO(0-IS-00-ff-00)[0x6120000e3020]{DONE}: Deallocated
<0004> abis_om2000.c:1871 OM2000-BTS(0)[0x612000010120]{WAIT-IS}: Received Event IS-DONE
<0004> abis_om2000.c:2404 OM2000-BTS(0)[0x612000010120]{WAIT-IS}: state_chg to WAIT-TRX-LAPD
<0014> input/lapd.c:660 ((0:1-T0-S0)) LAPD DL-ESTABLISH confirm TEI=0 SAPI=0
<0004> bts_ericsson_rbs2000.c:125 inp_sig_cb(): Input signal 'TEI-UP' received
<0003> osmo_bsc_main.c:299 bootstrapping RSL for BTS/TRX (0/0) on ARFCN 55 using MCC-MNC 262-42 LAC=1 CID=0 BSIC=63
<0017> input/dahdi.c:263 E1TS(0:1) TX: 0c 11 01 80 1e 01 27 17 55 06 19 00 00 00 00 00 00 00 00 00 40 00 00 00 00 00 00 e5 04 00 2b 
<0003> abis_rsl.c:1237 (bts=0,trx=0) ERROR REPORT (cause=Message Sequence Error [ 62 11 ])
<0017> input/dahdi.c:263 E1TS(0:1) TX: 0c 11 01 80 1e 02 27 17 59 06 1a 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff e5 04 00 
<0003> abis_rsl.c:1237 (bts=0,trx=0) ERROR REPORT (cause=Message Sequence Error [ 62 11 ])
<0017> input/dahdi.c:263 E1TS(0:1) TX: 0c 11 01 80 1e 0a 
<0003> abis_rsl.c:1237 (bts=0,trx=0) ERROR REPORT (cause=Message Sequence Error [ 62 11 ])
<0017> input/dahdi.c:263 E1TS(0:1) TX: 0c 11 01 80 1e 0b 
<0003> abis_rsl.c:1237 (bts=0,trx=0) ERROR REPORT (cause=Message Sequence Error [ 62 11 ])
<0017> input/dahdi.c:263 E1TS(0:1) TX: 0c 11 01 80 1e 29 
<0003> abis_rsl.c:1237 (bts=0,trx=0) ERROR REPORT (cause=Message Sequence Error [ 62 11 ])
<0017> input/dahdi.c:263 E1TS(0:1) TX: 0c 11 01 80 1e 03 27 17 49 06 1b 00 00 62 f2 24 00 01 c9 03 05 27 45 00 e5 04 00 29 2b 2b 2b 
<0003> abis_rsl.c:1237 (bts=0,trx=0) ERROR REPORT (cause=Message Sequence Error [ 62 11 ])
<0017> input/dahdi.c:263 E1TS(0:1) TX: 0c 11 01 80 1e 04 27 17 31 06 1c 62 f2 24 00 01 45 00 e5 04 00 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
<0003> abis_rsl.c:1237 (bts=0,trx=0) ERROR REPORT (cause=Message Sequence Error [ 62 11 ])
<0017> input/dahdi.c:263 E1TS(0:1) TX: 10 1a 1e 05 0b 00 12 06 1d 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
<0017> input/dahdi.c:263 E1TS(0:1) TX: 10 1a 1e 0d 
<0017> input/dahdi.c:263 E1TS(0:1) TX: 10 1a 1e 0e 
<0003> abis_rsl.c:1237 (bts=0,trx=0) ERROR REPORT (cause=Service or Option not available [ 3f ])
<0017> input/dahdi.c:263 E1TS(0:1) TX: 10 1a 1e 06 0b 00 0c 06 1e 00 00 62 f2 24 00 01 27 ff 2b 
<0004> fsm.c:322 OM2000-BTS(0)[0x612000010120]{WAIT-TRX-LAPD}: Timeout of T0
<0004> abis_om2000.c:2519 OM2000-BTS(0)[0x612000010120]{WAIT-TRX-LAPD}: Received Event TRX-LAPD-UP
<0004> abis_om2000.c:2424 OM2000-BTS(0)[0x612000010120]{WAIT-TRX-LAPD}: state_chg to WAIT-TRX
<0004> fsm.c:461 OM2000-TRX(0-0)[0x6120000eb8a0]{INIT}: Allocated
<0004> abis_om2000.c:65 OM2000-TRX(0-0)[0x6120000eb8a0]{INIT}: is child of OM2000-BTS(0)[0x612000010120]
<0004> abis_om2000.c:2286 OM2000-TRX(0-0)[0x6120000eb8a0]{INIT}: Received Event START
<0004> abis_om2000.c:2139 OM2000-TRX(0-0)[0x6120000eb8a0]{INIT}: state_chg to WAIT-TRXC
<0004> fsm.c:461 OM2000-MO(0-0-TRXC-00-ff-00)[0x6120000eba20]{INIT}: Allocated
<0004> abis_om2000.c:65 OM2000-MO(0-0-TRXC-00-ff-00)[0x6120000eba20]{INIT}: is child of OM2000-TRX(0-0)[0x6120000eb8a0]
<0004> abis_om2000.c:2019 OM2000-MO(0-0-TRXC-00-ff-00)[0x6120000eba20]{INIT}: Received Event START
<0004> abis_om2000.c:1685 OM2000-MO(0-0-TRXC-00-ff-00)[0x6120000eba20]{INIT}: state_chg to WAIT-RES-COMPL
<0004> abis_om2000.c:1114 Tx MO=TRXC/00/ff/00 Reset Command

20200703-rbs2k-10.pcap 20200703-rbs2k-10.pcap 38.2 KB working bring-up laforge, 07/04/2020 07:14 PM

History

#1 Updated by laforge 4 months ago

  • Description updated (diff)

So what we can see is that the TRX and the TRXC are not yet initialized on OM2K.

#2 Updated by laforge 4 months ago

what is interesting is:

<0014> input/lapd.c:660 ((0:1-T0-S62)) LAPD DL-ESTABLISH confirm TEI=0 SAPI=62
<0004> bts_ericsson_rbs2000.c:125 inp_sig_cb(): Input signal 'TEI-UP' received
...
<0014> input/lapd.c:660 ((0:1-T0-S0)) LAPD DL-ESTABLISH confirm TEI=0 SAPI=0
<0004> bts_ericsson_rbs2000.c:125 inp_sig_cb(): Input signal 'TEI-UP' received
<0003> osmo_bsc_main.c:299 bootstrapping RSL for BTS/TRX (0/0) on ARFCN 55 using MCC-MNC 262-42 LAC=1 CID=0 BSIC=63
<0003> abis_rsl.c:1237 (bts=0,trx=0) ERROR REPORT (cause=Message Sequence Error [ 62 11 ])
...
<0004> fsm.c:322 OM2000-BTS(0)[0x612000010120]{WAIT-TRX-LAPD}: Timeout of T0
<0004> abis_om2000.c:2519 OM2000-BTS(0)[0x612000010120]{WAIT-TRX-LAPD}: Received Event TRX-LAPD-UP
<0004> abis_om2000.c:2424 OM2000-BTS(0)[0x612000010120]{WAIT-TRX-LAPD}: state_chg to WAIT-TRX
<0004> fsm.c:461 OM2000-TRX(0-0)[0x6120000eb8a0]{INIT}: Allocated

WAIT_TRX_LAPD sounds like we wait for LAPD to be established. But we did get both SPAI0 and SAPI62 established before ?

#3 Updated by laforge 4 months ago

In Change-Id I55a06e08b9c52ff6e97e8c72f2d55770809eba51 we see how its supposed to work:

    om2k: Wait for OM TRX links to stabilize before trying to bring up TRX

    The OM2K link "per-trx" only comes up after MCTR is setup. So that means
    we need to wait for it before trying to boot the TRX itself.

    He we simply apply a "dumb" 5 sec timeout as this is the most reliable
    way I found to get this working reliably.

    Tracking the link state proved difficult and unreliable:

     - Multiple TRX can be present with their link coming up in random
       order.

     - They can already be up at the start (BTS already initialized from
       a previous boot) and so the link may actually come up, down, and
       up again.

     - All of theses transitions might happens before/after we get to the
       OM2K_BTS_S_WAIT_TRX state depending on how the LAPD timeout
       expire, if the BTS config was actually changed or not and how much
       time it takes to apply the new config.

    So all in all, what we must do is wait for the link to stabilize ...
    hence just waiting 5 second.

#4 Updated by laforge 4 months ago

  • % Done changed from 0 to 10

after a successive re-start of osmo-bsc, the RSL initialization seems to work now on my RBS2308. So I guess we have to find some kind of method to hold back (or at least re-attempt) the RSL bring-up after the OM2000-TRX FSM is complete. (TRX-DONE event to OM2000-BTS FSM).

#5 Updated by laforge 4 months ago

Attaching pcap file of a working (second, further) osmo-bsc start. You can see that initially the RSL bring-up fails, then all of the OM2K completes and finally RSL succeeds.

In a previous attempt this didn't appear to work, though somehow I cannot find evidence in my (not 100% complete) pcap files of earlier attempts.

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