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Community Member

Two questions about isdn backup

I have a router A with two bri-interfaces. Both are set to call up a backuprouter B in case of loosing leased line, but I only manage to get one of the bri's to call out. Can two bri both be member of the same dialer pool? I get this message from the one not working:

LOFOTNETT-GW#isdn call int bri 1/0 21319608

LOFOTNETT-GW#

Feb 27 10:09:35: BRI1/0 DDR: Attempting to dial 21319608

Feb 27 10:09:35: %ISDN-6-LAYER2UP: Layer 2 for Interface BR1/0, TEI 74 changed to up

Feb 27 10:09:37: BRI1/0: wait for isdn carrier timeout, call id=0x8248

Feb 27 10:09:53: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BR1/0, TEI 74 changed to down

Question 2: The backuprouter B is made to take calls from a number of routers who's lost their leased line, but how do I solve the remote-name command under the dialer interface, I am only allowed to set a single remote-name commande, not multiple. Before we used dialer maps, but is now trying to make å config with dialer profiles? Hope someone can help me out. Kristine

6 REPLIES
Cisco Employee

Re: Two questions about isdn backup

1) YES..the two or many bri interfaces can be groupped togather in a single dialer interface like this.

int bri0

dialer rotary-group 1

!

int bri1

dialer rotary-group 1

!

interface dialer 1

Now the ip address and dialer string etc needs to be configured under the "interface dialer 1" to call out to router B in your case.

Here is the url which discuss that.

http://www.cisco.com/warp/public/129/15.html

Now with this config, if the things dosen't work, we need to debug that.

2)You can create multiple dialer profile (dialer interface) which can be linked to a single physical interface. you can configure a different "dialer remote-name xxx" under different dialer interface to terminate the calls from the different routers.

Here is the place which discuss that

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/dial_c/dcdbakdp.htm

http://www.cisco.com/warp/public/793/access_dial/ddr_dialer_profile.html

Community Member

Re: Two questions about isdn backup

Thanks for answering, but 1) If I try to config dialer-rotary group, then I have to remove dialer pool member, which I thought had the same purpose with connecting the bri-interfaces, and I still want to try if I can make it work with the dialer profile config (dialer pool). What debug should I try to find out what's wrong, and is there another way to trigger a call except call manually with isdn call int bri....( and not plug out the leased line) ?

2)Ok, multiple dialer profile is one way to terminate calls from multiple routers, but what about dialer maps under the dialer interface, with ip adress and name on the remote router, is that going to work, or maybe it's posible to only authenticate from the remote router (ppp authentication chap calling) ?

Kristine

Cisco Employee

Re: Two questions about isdn backup

1)You can either use "dialer profile" or "dialer rotary-group" for a interface because both serves different purpose.

To know the things are working or not, following debug helps

debug dialer

debug ppp authentication

Now to trigger the call, you can use that "isdn call..." command or create an interesting traffic. And simplest way to create it is "ping"

You can ping a ip address, which is reachable via isdn or dialer interface which trigger the router to callout.

2)Dialer maps are not allowed under the dialer profiles but you can use a "dialer remote-name" instead to bind the calls. So each dialer interface will terminate a call from a remote router with a name specified in a "dialer remote-name xxx"command.

Thx..Tejal

Community Member

Re: Two questions about isdn backup

1) Ok, but if I use rotary group, and remove the dialer pool, will the backup int dialer..command under the serial interface still work? And, ping won't trigger the call as long as the serial is up, even if I ping the central site dialer interface, the ping goes over the leased line, the route to th esentral backup router isn't in th erouting table as long as the serial is up, or have i misunderstood this?

2) It is possible to write the dialer map command under the dialer interface, what do you mean by saying it's not allowed?

Kristine

Cisco Employee

Re: Two questions about isdn backup

1)YES if the serial (primary) line is up, then the ping will go over it. Now in that case the only option left for you is "isdn call ...." command.

2)It means its not allowed when you use the "dialer profile"

YES..dialer map command is possible to enter under the dialer interface if you bind the dialer interfac e and physical interface using "dialer rotary-group" command unde the physical interface (bri/pri).

But router will complain about it if you are trying to enter that command under the dialer interface which was binded with physical interface using "dialer pool" command..Which is a dialer profile..

Hope this clears..

Community Member

Re: Two questions about isdn backup

I would think you could use extended ping to specify that you are pinging FROM a SPECIFIC interface and the ping won't go over the serial (leased line) that is up.

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