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ISDN Dial works only ONCE at startup


I am trying to configure an ISDN line from Paris to Singapore.

The following configs are abstracts from both routers.

I included a log of a success connection and a failing connection.

Of course I cannot get the debug log from Singapore.

The configuration is fine because it works ONCE.

If you try again after the timeout and the releasing of the ISDN line you get

the following when attempting a telnet:

BR0/0:1 LCP: TIMEout: State REQsent

BR0/0:1 LCP: O CONFREQ [REQsent] id 90 len 31

BR0/0:1 LCP: AuthProto CHAP (0x0314C12404)

BR0/0:1 LCP: MagicNumber 0x31878D89 (0x050631878D89)

BR0/0:1 LCP: MRRU 1524 (0x110405F4)

BR0/0:1 LCP: EndpointDisc 1 ROUT_PARIS (0x130C01524F5554546543)

If then you just restart the router in Singapore you can then connect once


When we want to work for a long time we issue a never ending ping to the

router to keep the line open.

I have seen the same behaviour in a forum. Usually the "LCP:O CONFREQ" with

timeout is often pointed as a ISDN / SPEED Mismatch. But in this case I am more

in doubt with a handle release problem in IOS.

I know that version are quite old but do you have a workaround and can you point

me to the most recent firmware than could correct this.


Francois M. Malaspina (Nagravision)


Re: ISDN Dial works only ONCE at startup

Hi Francois ,

You are trying to establish an isdn connection from Paris to singapore ...correct...

If you observe the bri interface config of Singapore router you have configured dialer pool-member 1 which is used for lysis isdn connectivity.

Change the Bri config as below and check it once.

interface BRI0

no ip address

encapsulation ppp

dialer pool-member 3

no peer default ip address

isdn switch-type basic-net3

no cdp enable

ppp callback accept

ppp authentication chap

ppp multilink


interface Dialer3

ip address 192.168.3.Singapore

encapsulation ppp

dialer pool 3

dialer remote-name ROUT_PARIS

dialer idle-timeout 300

dialer-group 1

no peer default ip address

no cdp enable

ppp authentication chap

include dialer caller XXXXX under dialer interface 3.



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