How to test dial backup

[cbeazley]

I have two 2505 routers that I need to communicate with each other via the async backup interface but when I send a ping to initiate the modem the modem doesn't respond. I just get timed out. I have tested reverse telnet and all is good.

Any ideas how to get my modem responding to the ping request ?

 

[svermill]

Regardless of which line you are using, I would recommend that you read through this:

http://www.cisco.com/warp/public/76/9.html

Please pay particular attention to the part about configuring the modem with the 'modem autoconfigure' command under router(config-line)#.

 

[cbeazley]

Yep my modem is aux 1:
******************************************************
Tty Typ Tx/Rx A Modem Roty AccO AccI Uses Noise Overruns
* 0 CTY - - - - - 0 5 0/0
1 AUX 38400/38400 - inout - - - 0 0 0/0
2 VTY - - - - - 0 0 0/0
3 VTY - - - - - 0 0 0/0
4 VTY - - - - - 0 0 0/0
5 VTY - - - - - 0 0 0/0
6 VTY - - - - - 0 0 0/0
*******************************************************

I have cleaned up the route statements and am looking at your link.

I also noticed that cicso has a doc out that states that (at least for the 2500) it can't be done without having the primary link active first. In this case I may have to somehow simulate the primary link and then yank it.

 

[svermill]

OK. That may be the case. However, I think that you normally include a modem config statement under your line configuration. That may help.

 

[cbeazley]

Ah yes. I must have accidentally deleted the line when I modified the config. There actually is 'modem autoconfigure discovery' under my line.

The last doc link you sent me was interesting. I was able to run a diagnostic check for discovering my modem (even though I could rev telnet). It detected the modem just fine. The issue I think is routing. It doesn't want to route to my async interface until it has seen the primary interface. This is where your static route encouraged me but it didn't work. There must be a way to do this but I have gone ahead and ordered a serial connector cable to simulate an active serial line. Until I get the cable I will keep working on it.

Thanks for all your help. At least you have widened my knowledge of routers.

 

[svermill]

I wonder...did you ever remove the 'backup interface' command under your serial interface and then try it? That may very well be preventing async 1 from ever kicking in, since, as you pointed out, serial 0 was never up in the first place.

Also, you may want to think about adding a 'hold-queue' on your async interface. This queues packets while dialing is taking place.

 

[cbeazley]

Almost there....

Well I tried this before but am trying it again. Now it is actually trying to connect. Yea baby. But it fails each time and states that it is expecting a 'connect'. I need it to connect via the 'dialer map ip 10.123.251.1 name test modem-script dialup broadcast 236-3535' command otherwise the chat-script wont work.

 

[svermill]

If you don't figure it out soon, try pasting your error message here (requires login):

http://www.cisco.com/cgi-bin/Support/Errordecoder/home.pl

Otherwise, paste it here and we'll figure out what is going wrong.

 

[cbeazley]

Here is the debug:


Async1: sending broadcast to ip 10.123.251.1 -- failed, not connected
CHAT1: Timeout expecting: CONNECT
CHAT1: Chat script dialup finished, status = Connection timed out; remote host not responding
Async1: Async Interface dial-out failure
TTY1: Modem command: --AT&F&C1&D2&H1&R2&M4&K1&B1S0=1H0--
TTY1: Modem configuration succeeded
TTY1: detection speed (38400) response ---OK---
TTY1: Done with modem configuration
Async1: re-enable timeout
Async1: No dialer string, dialing cannot occur
Async1: sending broadcast to ip 10.123.251.1
get_free_dialer: faking it
Async1: Dialing cause: Async1: ip PERMIT
Async1:No holdq created - not configured
Async1: Attempting to dial 236-3535
CHAT1: Attempting async line dialer script
CHAT1: Dialing using Modem script: dialup & System script: none -- failed, not connected
CHAT1: process started
CHAT1: Asserting DTR
CHAT1: Chat script dialup started
CHAT1: Sending string: AT Z
CHAT1: Expecting string: OK
CHAT1: Completed match for expect: OK
CHAT1: Sending string: ATDT\T
CHAT1: Expecting string: CONNECT
Async1: sending broadcast to ip 10.123.251.1 -- failed, not connected

 

[cbeazley]

Ok even closer now. I have dial out working but the chap drops but I think I just need to synch the password between the routers. No problem. The real reason behind doing this is to resolve 56k modem issues. The 33.6 usr courier modem has no problems but the 56k user courier (even though the router detects it) refuses to dial out.

 

[svermill]

Looks like the call simply isn't going through. Are you tied through a pbx in your lab or something? Do your modems have speakers? Can you tell if any call progress is being made? It looks as if your router is properly configuring the modem. What about on the other end. Is the router properly configuring the modem to accept calls? If it appears that the call is being made and answered, I would try extending your timeout from 30 seconds to 45:

chat-script dialup ABORT ERROR "" "AT Z" OK "ATDT\T" TIMEOUT 45 CONNECT


Also, I would recommend that you add that 'dialer hold-queue' of some value. Perhaps to 5 or 10.

 

[svermill]

The chap password must be the same on both routers for the hash to work.

 

[cbeazley]

Well I think I've tried everything. Phone lines are clear, it dials out but chap dial back doesn't seem to kick in.

I do appreciate all you help though and when I finally figure this out I will let you know.

I have purchased a serial xover cable so I can try to get the serial lines up first.