The Care and Feeding of ISDN4BSD
10.4 Troubleshooting the PPP	10.4 Troubleshooting the PPP	10.4.2 sppp Problems

10.4.1 ISDN Problems

Sometimes the local or remote numbers are wrong, some dial prefixes may be required and are missing or the remote side does not accept the call because its busy or not setup properly. First you should have a look in your isdnd's logfile or in /var/log/messages to see what went wrong. Another method to diagnose ISDN problems is to use the isdntrace utility (see also section 7). The following example output shows a successful connection to the Cisco 1003 for our PPP setup example:

- TE->NT - unit:0 - frame:004672 - time:25.02 10:21:58.861463 - length:28 ---

Dump:000  00 81 00 00                                           ....

Q921: SAP=0 (Call Control), C, TEI=64, I-Frame: N(S) 0 N(R) 0 P 0

Dump:004  08 01 35 05 a1 04 02 88 90 18 01 83 6c 04 81 32       ..5.........l..2

Dump:020  34 31 70 04 81 35 38 31                               41p..581

Q931: pd=Q.931/I.451, cr=0x35 (from origination), message=SETUP:

     [sending complete]

     [bearer capability:

          cap=unrestricted digital information

          std=CCITT

          rate=64 kbit/s

          mode=circuit]

     [channel id: channel=any channel (preferred)]

     [calling party number: 241 (type=unknown, plan=ISDN)]

     [called party number: 581 (type=unknown, plan=ISDN)]

 

- NT->TE - unit:0 - frame:004673 - time:25.02 10:21:58.891458 - length:4 ---

Dump:000  00 81 01 02                                           ....

Q921: SAP=0 (Call Control), R, TEI=64, S-Frame: RR N(R) 1 PF 0

 

- NT->TE - unit:0 - frame:004674 - time:25.02 10:21:59.121458 - length:15 ---

Dump:000  02 81 00 02                                           ....

Q921: SAP=0 (Call Control), C, TEI=64, I-Frame: N(S) 0 N(R) 1 P 0

Dump:004  08 01 b5 0d 18 01 89 1e 02 81 88                      ...........

Q931: pd=Q.931/I.451, cr=0x35 (from destination), message=SETUP ACKNOWLEDGE:

     [channel id: channel=B-1 (exclusive)]

     [progress ind: Std=CCITT, Loc=Private network serving local user

          Description: In-band info or appropriate pattern now available]

 

- TE->NT - unit:0 - frame:004675 - time:25.02 10:21:59.121458 - length:4 ---

Dump:000  02 81 01 02                                           ....

Q921: SAP=0 (Call Control), R, TEI=64, S-Frame: RR N(R) 1 PF 0

 

- NT->TE - unit:0 - frame:004676 - time:25.02 10:22:00. 41472 - length:18 ---

Dump:000  02 81 02 02                                           ....

Q921: SAP=0 (Call Control), C, TEI=64, I-Frame: N(S) 1 N(R) 1 P 0

Dump:004  08 01 b5 07 18 01 89 29 05 63 02 19 0a 19             .......).c....

Q931: pd=Q.931/I.451, cr=0x35 (from destination), message=CONNECT:

     [channel id: channel=B-1 (exclusive)]

     [date/time: 25.02.99 10:25]

 

- TE->NT - unit:0 - frame:004677 - time:25.02 10:22:00. 41472 - length:8 ---

Dump:000  00 81 02 04                                           ....

Q921: SAP=0 (Call Control), C, TEI=64, I-Frame: N(S) 1 N(R) 2 P 0

Dump:004  08 01 35 0f                                           ..5.

Q931: pd=Q.931/I.451, cr=0x35 (from origination), message=CONNECT ACKNOWLEDGE: