Callback timesout when dialing back to the client

[mustafa.mail]

Hi,

I have 3640 with E1 ISDN PRI and 30 Digital Modems, I have configured the callback feature for dial-up clients. The connection times-out with callback feature. The client dial-in - gets authenticated - modem drops and dials the number configured for the client. The client gets the message waiting for callback and then fails. The debug output on the router shows

5d03h: TTY0: timer type 1 expired

5d03h: TTY0: Exec timer (continued)

5d03h: CHAT42: Timeout expecting: CONNECT

5d03h: CHAT42: Chat callback finished, status = Connection timed out; remote host not responding

5d03h: TTY42: Line reset by "Async dialer"

I have done the config for async-ppp for callback as per cisco website guidelines.

Can anyone help?

Regards,

Mustafa

[makchitale]

The process from the 3640 looks correct, that is, after negotating callback , drop the call & make a callback.

1)Can you reverse telnet into a modem & dialout using ATDTxxxxxx (where xxxxxx is the same number as seen in the chat script) and connect fine?

Thanks, Mak.

[mustafa.mail]

Hi,

The result is same. The client modem does not train-up and disconnects after a continuous tone.

Rgds,

Mustafa

[tepatel]

In that case its a modem or a analog line problem at dialin client side. Is that analog line provisioned to receive a call? Also try to change the modem if possible.

[p.sage]

Hi, I have a similar problem with an AS5350 with an E1 PRI and the DFC card. The Client (win2K) dials in ok, and you are prompted for the callback number. The server then goes through the hang up process and calling back, but the client sits there say "preparing for callback" and then "waiting for modem reset". After a while it just gives a disconect error. I think the poblem is related to the server 'disconnect' not being seen properly by the client, so its still waiting for the disconect to finish before it will start to listen for the callback.

Any ideas on where I can look next would be appreciated. Sorry it't not a solution for you, but have you tried bebug dialer, debug callback, debug isdn events etc?

[tepatel]

We can easily debug that issue from aS5350 side using following debug

debug isdn q931

debug spe modem stat

debug ppp nego

debug chat

debug ppp cbcp

debug ppp callback

debug modem

debug aaa authorization

with that we should be able too see that AS5350 is releasing the line at ISDN layer and modem layer too. With debug chat we can see how far it proceeds for callback.