Posted: Fri May 22, 2009 4:58 pm Post subject: [asterisk-users] BT ISDN-30 Pri getting 'stuck' on outgoing
I've having problems with a BT 2 span ISDN-30/Digium TE205P asterisk
setup with outgoing calls not completing and requiring an Asterisk reset
to 'unstick' span 1.
Sorry this is a bit long but I'm completely out of my depth :-(
This system has been in use for some while and I recently upgraded it to
asterisk 1.4.24, zaptel 1.4.11 and libpri 1.4.9. I didn't change
/etc/zaptel.conf or zapata.conf.
The upgrade fixed the problems with calls getting stuck in voicemail and
a few other issues but the inability to make outgoing calls that started
a couple of days after the upgrade is a bit of a bigger problem!
Initially it looked like a BT fault and indeed BT agreed that there was
a problem with a 'card in the exchange'. However they say that they've
changed that and the problem's still happening :-(
It's not consistently failing. On Tuesday it was fine. On Wednesday it
failed 7 times, Thursday 4 and today 11. This could be down to usage
though (more calls being made). Each time span 1 won't complete
outgoing calls we have to restart asterisk and then it comes right back
for a while. Span 2 (which only has 8 channels enabled) seems to
continue working.
BT have now installed an ISDN monitor and their engineer is saying that
there are problems with Asterisk generating "malformed" packets and "out
of sequence" packets.
Here's what the BT engineer said including examples from his ISDN
monitor of the failures (some asterisk pri debug logs follow that).
Can anyone suggest a course of action here? While I can happily
construct dialplans and stuff, this level of ISDN is completely beyond
my experience.
Here's the BT chappies report:
Quote:
I've had a good look at the trace containing yesterday afternoon's failures.
There seem to be 2 issues that I think are closely related.
Malformed Packets
Intermittently packets sent by the PBX are malformed. My analyser shows them
as CRC-Errors, but, in fact, when you study the data in hex you see that,
quite simply, some information is missing. Like my analyser, the exchange
doesn't understand these malformed packets and ignores them which means that
the next packet sent by the PBX has an incorrect "sequence number" and is
rejected by the exchange. The exchange then asks for the packet with the
correct sequence number to be resent.
This is happening intermittently throughout the trace; when it happens at
quieter periods the correct sequence is quickly recovered and call
processing carries on. When it happens at busier periods, or when there are
two or more incorrect packets close together, things quickly start to get
out of control with the sequence between exchange and PBX (that has to be
followed) getting further and further apart. Eventually we start to see the
layer 3 "call reset" messages that we were looking at yesterday morning, but
even these can't recover the situation because the sequence is so far out.
The only cure (as we know) is a complete PBX or exchange reset which
re-establishes the packet sequence and allows calls to be passed once again.
There are occasions when the PBX simply sends "layer 3" messages that are
out-of-sequence. They are not malformed this time, simply out-of-sequence.
Once again the rejection / recovery process begins, but, if this happens at
a busy time the consequence will be the same.
<<Message out of sequence>>
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-
12:17:54/317.9 1- RS D1 BOP FRAME flg=3D999 =
[0033]
D2 Q921 (S:00 T:000 C/R:1) I P:0 NR:092 NS:048 =
[0029]
D3 Q931 Pro:08 Ref:(O,00 c7) SETUP =20
IE:(0/a1) len:0 >> Sending complete
IE:(0/04) len:3 >> Bearer capability
Oct 3 : -00----- Coding =3D ITU-T
---00000 Capability =3D Speech
Oct 4 : -00----- Transfer mode =3D Circuit
---10000 Transfer rate =3D 64 kbits/s
Oct 5 : -0100011 L1 protocol =3D G711 A-law
IE:(0/18) len:3 >> Channel identification
Oct 3 : -0------ Int id =3D implicit
--1----- Interface =3D Primary
----0--- Preferred/Exclusive =3D =
Preferred
------01 Channel select =3D Indication =
follows
Oct 32: -00----- Coding =3D ITU-T
---0---- Number/Map =3D Number
----0011 Type =3D B-channel
Oct 33: ---00100 Channel number =3D 4
IE:(0/6c) len:2 >> Calling party number
Oct 3 : -000---- Type of number =3D Unknown
----0000 Numbering plan=3D Unknown
Oct 3a: -01----- Presentation =3D Restricted
------11 Screening =3D Network =
provided
Oct 4 : ******** Number =3D=20
IE:(0/70) len:7 >> Called party number
Oct 3 : -000---- Type of number =3D Unknown
----0001 Numbering plan=3D ISDN/tel. =
(E164/E163)
Oct 4 : ******** Number =3D 846060
12:17:54/321.9 1- TS D1 BOP FRAME flg=3D999 =
[0004]
D2 Q921 (S:00 T:000 C/R:1) RR P/F:0 NR:049
12:17:54/323.9 1- TS D1 BOP FRAME flg=3D010 =
[0004]
D2 Q921 (S:00 T:000 C/R:1) RR P/F:0 NR:049
12:17:54/326.0 1- TS D1 BOP FRAME flg=3D002 =
[0013]
D2 Q921 (S:00 T:000 C/R:0) I P:0 NR:049 NS:093 =
[0009]
D3 Q931 Pro:08 Ref:(D,00 c7) ALERTING =20
IE:(0/1e) len:2 >> Progress indicator
Oct 3 : -00----- Coding =3D ITU-T
----0001 Loc =3D Private net to local =
usr
Oct 4 : -0001000 8 =3D In-band info now =
available
12:17:54/334.5 1- RS D1 BOP FRAME flg=3D127 =
[0004]
D2 Q921 (S:00 T:000 C/R:0) REJ P/F:0 NR:092
12:17:54/340.1 1- TS D1 BOP FRAME flg=3D097 =
[0014]
D2 Q921 (S:00 T:000 C/R:0) I P:0 NR:049 NS:092 =
[0010]
D3 Q931 Pro:08 Ref:(D,00 c7) CALL PROCEEDING =20
IE:(0/18) len:3 >> Channel identification
Oct 3 : -0------ Int id =3D implicit
--1----- Interface =3D Primary
----1--- Preferred/Exclusive =3D =
Exclusive
------01 Channel select =3D Indication =
follows
Oct 32: -00----- Coding =3D ITU-T
---0---- Number/Map =3D Number
----0011 Type =3D B-channel
Oct 33: ---00100 Channel number =3D 4
12:17:54/342.1 1- TS D1 BOP FRAME flg=3D001 =
[0013]
D2 Q921 (S:00 T:000 C/R:0) I P:0 NR:049 NS:093 =
[0009]
D3 Q931 Pro:08 Ref:(D,00 c7) ALERTING =20
IE:(0/1e) len:2 >> Progress indicator
Oct 3 : -00----- Coding =3D ITU-T
----0001 Loc =3D Private net to local =
usr
Oct 4 : -0001000 8 =3D In-band info now =
available
12:17:54/344.4 1- RS D1 BOP FRAME flg=3D073 =
[0004]
D2 Q921 (S:00 T:000 C/R:0) RR P/F:0 NR:093
12:17:54/354.4 1- RS D1 BOP FRAME flg=3D074 =
[0004]
D2 Q921 (S:00 T:000 C/R:0) RR P/F:0 NR:094
12:17:56/741.6 1- RS D1 BOP FRAME flg=3D999 =
[0013]
D2 Q921 (S:00 T:000 C/R:1) I P:0 NR:094 NS:049 =
[0009]
D3 Q931 Pro:08 Ref:(O,00 c0) DISCONNECT =20
IE:(0/08) len:2 >> Cause
Oct 3 : -00----- Coding =3D ITU-T
----0000 Loc =3D User
Oct 4 : -0010000 016 =3D Normal clearing
I cannot see any issues or anomalies with the BT ISDN30 service.
There appear to problems with the creation and sequencing of "layer 3"
messages; most often (but not exclusively) the message affected is "Call
Proceeding".
British Telecommunications plc. Registered office: 81 Newgate Street London
EC1A 7AJ
Registered in England no: 1800000
and here's a pri debug log for a failing state (it's tricky to get clean
examples because of the call volume going on but I think this is right).
Failing call:
Quote:
Protocol Discriminator: Q.931 (8) len=39
Call Ref: len= 2 (reference 844/0x34C) (Originator)
Message type: SETUP (5)
[04 03 80 90 a3]
Bearer Capability (len= 5) [ Ext: 1 Q.931 Std: 0 Info transfer capability: Speech (0)
Ext: 1 Trans mode/rate: 64kbps, circuit-mode (16)
User information layer 1: A-Law (35)
[18 03 a9 83 9a]
Channel ID (len= 5) [ Ext: 1 IntID: Implicit PRI Spare: 0 Exclusive Dchan: 0
ChanSel: As indicated in following octets
Ext: 1 Coding: 0 Number Specified Channel Type: 3
Ext: 1 Channel: 26 ]
[6c 08 00 80 38 34 36 30 38 30]
Calling Number (len=10) [ Ext: 0 TON: Unknown Number Type (0) NPI: Unknown Number Plan (0)
Presentation: Presentation permitted, user number not screened (0) '846080' ]
[70 0c 80 30 31 37 38 30 34 37 31 38 30 32]
Called Number (len=14) [ Ext: 1 TON: Unknown Number Type (0) NPI: Unknown Number Plan (0) '01780471802' ]
q931.c:3128 q931_setup: call 33612 on channel 26 enters state 1 (Call Initiated)
-- T200 counter expired, What to do...
-- Retransmitting 43 bytes
q931.c:2810 q931_call_proceeding: call 2 on channel 7 enters state 9 (Incoming Call Proceeding)
Delaying transmission of 77, window is 7/7 long
Stopping T_203 timer
Starting T_200 timer
-- Restarting T200 timer
Quote:
Protocol Discriminator: Q.931 (8) len=10
Call Ref: len= 2 (reference 2/0x2) (Terminator)
Message type: CALL PROCEEDING (2)
[18 03 a9 83 87]
Channel ID (len= 5) [ Ext: 1 IntID: Implicit PRI Spare: 0 Exclusive Dchan: 0
ChanSel: As indicated in following octets
Ext: 1 Coding: 0 Number Specified Channel Type: 3
Ext: 1 Channel: 7 ]
q931.c:2838 q931_alerting: call 2 on channel 7 enters state 7 (Call Received)
Delaying transmission of 78, window is 7/7 long
Starting T_200 timer
-- Restarting T200 timer
Quote:
Protocol Discriminator: Q.931 (8) len=9
Call Ref: len= 2 (reference 2/0x2) (Terminator)
Message type: ALERTING (1)
[1e 02 81 88]
Progress Indicator (len= 4) [ Ext: 1 Coding: CCITT (ITU) standard (0) 0: 0 Location: Private network serving the local user (1)
Ext: 1 Progress Description: Inband information or appropriate pattern now available. (8) ]
NEW_HANGUP DEBUG: Calling q931_hangup, ourstate Call Initiated, peerstate Overlap sending
q931.c:3009 q931_disconnect: call 33612 on channel 26 enters state 11 (Disconnect Request)
Delaying transmission of 79, window is 7/7 long
Starting T_200 timer
-- Restarting T200 timer
Quote:
Protocol Discriminator: Q.931 (8) len=9
Call Ref: len= 2 (reference 844/0x34C) (Originator)
Message type: DISCONNECT (69)
[08 02 81 90]
Cause (len= 4) [ Ext: 1 Coding: CCITT (ITU) standard (0) Spare: 0 Location: Private network serving the local user (1)
Ext: 1 Cause: Normal Clearing (16), class = Normal Event (1) ]
If you've got this far then Thanks! and well done!
Any help much appreciated.
--
Regards,
Russell
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| Russell Brown | MAIL: russell@lls.com PHONE: 01780 471800 |
| Lady Lodge Systems | WWW Work: http://www.lls.com |
| Peterborough, England | WWW Play: http://www.ruffle.me.uk |
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