ISDN Backup Dialer Configuration

[daniel.bowen]

Hi everyone,

I am trying to configure an ISDN router to dial over an ISDN line in the case of DR. I have pasted the configuration below and just need to ask a couple of questions:

Config of router to initiate line during DR

interface Serial1/0:15

no ip address

encapsulation ppp

dialer pool-member 1

isdn switch-type primary-net5

no fair-queue

ppp multilink

ppp timeout multilink link add 1

!

interface Dialer1

description ISDN PRI to 016xxxxxxx2

ip address 172.x.x.1 255.255.255.252

encapsulation ppp

dialer pool 1

dialer string 016xxxxx2

dialer-group 1

multilink load-threshold 1 either

ppp authentication chap

Config of router it is dialling

interface Serial1/0:15

no ip address

encapsulation ppp

dialer pool-member 1

isdn switch-type primary-net5

no fair-queue

ppp multilink

ppp timeout multilink link add 1

!

interface Dialer1

description ISDN PRI to 016xxxxxxx2

ip address 172.x.x.2 255.255.255.252

encapsulation ppp

dialer pool 1

dialer-group 1

multilink load-threshold 1 either

ppp authentication chap

1. Do I need to configure a dialer string on the second router, even if it is only being dialled by the first router?

2. Have I missed out any configuration that would stop this from working?

Many thanks in advance,

Daniel,

[Richard Burts]

1. No you do not need to configure a dialer string on the second router if it is only answering.

2. I would suggest including ppp authentication chap on both serial interfaces as well as the dialer interfaces.

There are a couple other things which you may have but not included such as defining names and password strings to use for Chap authentication; dialer lists to match the dialer groups.

Theree are a few questions which may impact how you should configure the router:

What kind of routing logic are you planning to use? (floating static, dynamic routing protocol, or what).

How are you planning to trigger the dialing? (backup interface, dialer watch, floating static route).