The infamous ISDN backup problem

Unanswered Question
Mar 11th, 2007
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Hi,


This darn this just won't dial. The client router says its dialing but I see no connections coming through on my side. Below an output of the config and debug q921. If I do "show isdn history" on client router, you can see the router is dialing....so where are the connections going?


Can anyone help?


!

interface Dialer0

description backup

ip address 192.168.225.238 255.255.255.252

no ip redirects

no ip unreachables

no ip proxy-arp

encapsulation ppp

no ip split-horizon

dialer pool 1

dialer remote-name cr1

dialer idle-timeout 180

dialer string <number>

dialer-group 1

fair-queue

no cdp enable

ppp authentication pap callin

ppp chap refuse

ppp pap sent-username <hostname> password <removed>

ppp multilink bap

ppp multilink links maximum 2

ppp multilink links minimum 2

ppp multilink endpoint string client-backup

!



#deb isd q921

#isd test call int br 0 <number>

001011: Mar 11 19:55:16.034 SAST: ISDN BR0 Q921: L2_EstablishDataLink: sending SABME

001012: Mar 11 19:55:16.034 SAST: ISDN BR0 Q921: User TX -> SABMEp sapi=0 tei=64

001013: Mar 11 19:55:16.054 SAST: ISDN BR0 Q921: User RX <- UAf sapi=0 tei=64

001014: Mar 11 19:55:16.054 SAST: %ISDN-6-LAYER2UP: Layer 2 for Interface BR0, TEI 64 changed to up

001015: Mar 11 19:55:16.058 SAST: ISDN BR0 Q921: User TX -> INFO sapi=0 tei=64, ns=0 nr=0

001016: Mar 11 19:55:16.090 SAST: ISDN BR0 Q921: User RX <- RR sapi=0 tei=64 nr=1

001017: Mar 11 19:55:16.230 SAST: ISDN BR0 Q921: User RX <- INFO sapi=0 tei=64, ns=0 nr=1

001018: Mar 11 19:55:16.234 SAST: ISDN BR0 Q921: User TX -> RR sapi=0 tei=64 nr=1

001019: Mar 11 19:55:16.282 SAST: ISDN BR0 Q921: User RX <- INFO sapi=0 tei=64, ns=1 nr=1

001020: Mar 11 19:55:16.282 SAST: ISDN BR0 Q921: User TX -> RR sapi=0 tei=64 nr=2

001021: Mar 11 19:55:16.290 SAST: ISDN BR0 Q921: User TX -> INFO sapi=0 tei=64, ns=1 nr=2

001022: Mar 11 19:55:16.314 SAST: ISDN BR0 Q921: User RX <- RR sapi=0 tei=64 nr=2

001023: Mar 11 19:55:16.334 SAST: ISDN BR0 Q921: User RX <- INFO sapi=0 tei=64, ns=2 nr=2

001024: Mar 11 19:55:16.334 SAST: ISDN BR0 Q921: User TX -> RR sapi=0 tei=64 nr=3

001025: Mar 11 19:55:18.326 SAST: ISDN BR0 Q921: User RX <- DISCp sapi=0 tei=64

001026: Mar 11 19:55:18.326 SAST: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BR0, TEI 64 changed to down

001027: Mar 11 19:55:18.330 SAST: ISDN BR0 Q921: User TX -> UAf sapi=0 tei=64

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Overall Rating: 5 (2 ratings)
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hoogen_82 Sun, 03/11/2007 - 12:16
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Hmm.. a debug q921 is meant for the Layer 2 link and troubleshooting layer 2 issues. It would be good if you could post the output of debug isdn q931 along with the show isdn status, show isdn active, show dialer to analyse your problem more.


On another note your layer 2 also seem to be going down. So shutdown and no shut the BRI interface and then do the isdn test call and capture the output i have asked for earlier.


Hoogen

dgahm Sun, 03/11/2007 - 15:49
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"No route to destination" is the reason the call is being immediately dropped by the ISDN switch.


Are you sure the number is being dialed correctly? Maybe you need a 1 for long distance? Or maybe you need a 10 digit number instead of 7? Your service provider can help you if the answer is not obvious.


Please rate helpful posts.

hoogen_82 Mon, 03/12/2007 - 02:10
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Just to add to the above post. Do you have on your serial interface configured something like backup interface bri or dialer?


Could you post your full config relating to ISDN.


Hoogen

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