Setting up ISDN as a backup to serial connection on a 1601

[ash786]

I am trying to do the above but having problems, I am afraid I am a novice at setting up ISDN on CISCO routers. Can someone help, this is my current config. Where have I gone wrong or is it a complete mess.

Current configuration:
!
version 11.1
service password-encryption
service udp-small-servers
service tcp-small-servers
!
hostname JHC_WAN
!
enable password x xxxxxxxxxxxxxxxxxxx
!
isdn switch-type basic-net3
!
interface Ethernet0
ip address xx.xx.xx.xx xx.xx.xx.xx
ip access-group 110 in
!
interface Serial0
backup interface BRI0
ip address xx.xx.xx.xx xx.xx.xx.xx
encapsulation ppp
compress stac
!
interface BRI0
ip address xx.xx.xx.xx xx.xx.xx.xx
encapsulation ppp
dialer string xxxxxxxxxxx
dialer-group 1
!
interface Dialer1
no ip address

 

[Saeed42]

You need to give the serial interface a delay time so you don't have a situation where the isdn line keeps flapping every time your leased line sneezes, the command is "backup delay 5 30," 5 is how long it will wait before the ISDN is activated and the 30 is the time it will wait before the isdn is torn down when your serial interface comes back on line.

Your BRI interface doesn't seem to have any authentication setup. You need to make sure the serial interface and the backup interface have the same IP address (ip unnumbered Serial0 for the BRI interface), you will also need to make sure that your route table has a static route for the backup interface and is set to higher Distance metric than all your other routes.

Hope that helps
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Don't be content with being average. Average is as close to the bottom as it is to the top
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

[ChrisAC]

This is an edited config from one of our leased lines with ISDN backup! It may be of some help.

Current configuration:
!
version 12.0
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname example
!
logging buffered 5000 debugging
aaa new-model
aaa authentication login word local
aaa authentication login CONSOLE none
aaa authentication ppp default if-needed local
enable secret 5 xxxxxxxxxxxxxxxxxxxxxxxxxx
!
username test password 7 xxxxxxxxxxxxxxx
username another password 7 xxxxxxxxxxxxx
ip subnet-zero
no ip source-route
ip name-server 212.50.000.000
ip name-server 213.249.000.000
isdn switch-type basic-net3
!
!
!
interface Ethernet0
ip address aaa.bbb.ccc.ddd 255.255.255.240
no ip redirects
no ip directed-broadcast
no ip proxy-arp
!
interface Serial0
backup interface Dialer1
ip address aaa.bbb.ccc.ddd 255.255.255.252
no ip directed-broadcast
encapsulation ppp
no fair-queue
down-when-looped
!
interface BRI0
no ip address
no ip directed-broadcast
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
!
interface Dialer1
ip unnumbered Ethernet0
no ip directed-broadcast
encapsulation ppp
dialer remote-name test
dialer idle-timeout 200 either
dialer enable-timeout 20
dialer wait-for-carrier-time 15
dialer string 0845000000
dialer caller x callback
dialer pool 1
dialer-group 1
no fair-queue
ppp authentication chap
ppp chap password 7 0000000000
!
ip classless
ip route 0.0.0.0 0.0.0.0 Serial0
ip route 0.0.0.0 0.0.0.0 Dialer1 200
!
dialer-list 1 protocol ip permit
!
line con 0
transport input none
line vty 0 4
!
end
************************
Chris Andrew, CCNA
chrisac@gmx.co.uk
************************