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isdn backup and static routing

I have two routers linked via a 56k circuit. I have installed ISDN as a backup line and can successfully make manual calls to the remote end. However I can't seem to route traffic over the ISDN line. The serial (56k) is not running unnumbered and is network The near end has a static route for this network pointing to the remote ends serial ports IP address ( On the remote end, no ethernet ports are enabled as I connect to an x25 network via a serial port. So TCP to X25 translation is taking place on this remote router.

I have tried using a floating static route with no success. Would the remote end having no active ethernet port be a issue? If so I was thinking about creating a loopback interface on that end and using the command "ip unnumbered loopback1" for the BRI0/0 port.

What else can I try on this scenario?

  • Other Network Infrastructure Subjects

Re: isdn backup and static routing

You don't need an ethernet port to get

this to work. Without seeing your

entire config, it's difficult to comment,

but in general something like this

should work:

int ser 0

ip addr


int br 0

ip addre

encap ppp

ppp authen chap

dialer-group 1

dialer map ip name remote 123456

ppp mult


ip route 200

! OR

ip route 200

! where is a reachable network

! address at the remote, used for translation


dialer-list 1 prot ip permit