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New Member

03x BRI at 2620 calling 03x BRI at 7206 as backup for Frame Relay

I have a 7206 at main site (HQ) with 32 serials and 08 BRI interfaces. At plant I have the main link from HQ arriving to a 3661 with Frame Relay, and in a remote unit (connected using Gigaethernet link) I have a 2620 with 08x BRI interfaces. What I wanna do is when main link fails, 03x BRI interfaces from 2620 connect to 7206 an work as backup link.


Re: 03x BRI at 2620 calling 03x BRI at 7206 as backup for Frame

This document can explain how to implement a dial backup solution for FR circuits:

And for your case consists of multilink PPP you'd better take a look at this for dialer interface and MLPPP config:


New Member

Re: 03x BRI at 2620 calling 03x BRI at 7206 as backup for Frame

Hi Kivanc,

Tks for tyour attention.

My main doubt know is about the isdn lines that are allways coming up even using passive-interface command. Do you know what could it be?

Re: 03x BRI at 2620 calling 03x BRI at 7206 as backup for Frame


Tell me if I understood wrong: Your remote site has one 3600 and one 2600, 3600 connects to HQ 7200 via FR but backup BRI links to the 7200 reside on the 2600, and there's a LAN connection between 3600 and 2600. If this is the case conventional dial backup solutions won't work because primary and backup links don't terminate on the remote. I can imagine two solutions:

1. Co nfigure dial-backup solution on the 7200 instead of the remote routers (FR and BRIs on the same router so as soon as FR goes down this 7200 can dial the remote 2600).

2. Configure two static default routes on the remote 3600: one through FR link and one pointing the 2600 BUT with a higher admin.distance (floating static routes). I'm assuming that all local traffic on the remote trying to get to the HQ is seeing 3600 as default gateway. And configure dial-on demand (not dial back-up) with MLPPP on the 2600 with a static default route to the HQ 7200 via BRIs. With this If FR goes down primary static default route on the 3600 will be out of the routing table and using the other static default route, all outgoing traffic will be routed to 2600 via LAN. And this traffic will trigger the dial-on demand on the 2600.

If you see BRI lines as up/up(spoofing) it's normal even when you don't use them. You can check if there's a call issuing "sh isdn status"

Best Regards.