ISDN to backup Microwave connection

[pllim]

Is it possible to use ISDN BRI connection to backup a Microwave connection (using Ethernet port)?

I have 2 Cisco routers connected using Motorola Canopy microwave link through the Ethernet ports of the routers. The microwave link is working fine.

On both routers, I have ISDN BRI port. Is it possible to use the ISDN connection as backup when the microwave link is down?

Thanks.

[pllim]

Just got back to work after a long holiday.

As per your advised, I changed the interface to ethernet 6/0 (which is connected to my fiber optic).

#route-map BW-ROUTE-MAP permit 10

#match ip address 101

#set interface ethernet 6/0

#exit

#ip local policy route-map BW-ROUTE-MAP

This time, my ISDN line works fine. It doesn't get activated when my fiber optic line is still working.

The next thing for me to test, is to see if the ISDN gets activated when the fiber optic line fails (by shutting down the interface ethernet6/0).

The 'ip route' on the 3661 router is changed -

ip route 10.40.0.0 255.255.0.0 10.130.40.12 track 40

ip route 10.40.0.0 255.255.0.0 Dialer3 150

When I shut my Ethernet6/0 interface, I can see that the ISDN is activated but I am no longer able to ping to 10.40.1.1. When I run the 'sh ip route' command, I could see -

S 10.40.0.0/16 is directly connected, Dialer3

Why can't I ping to 10.40.1.1 anymore after I have shutdown my ethernet6/0 interface?

[Richard Burts]

Lim

It looks to me like you have a route to 10.40.1.1 and should be sending ping to them. I would suggest that you check and their end and see how their traffic response tries to get to you. Does it come back over the ISDN or does it still try to use the normal routing over the primary connection?

Remember that when ping fails it might mean that your packets do not get to the destination but it might also mean that responses from the destination do not get back to you.

HTH

Rick

[pllim]

Before I switch to use the microwave link, my ISDN backup was working fine. I could ping from my 3660 (10.30.1.1) router to 3640 (10.40.1.1) when using the ISDN line.

The only change made to the 3640 router (to use the microwave) was the ip route -

no ip route 0.0.0.0 0.0.0.0 10.130.40.1 (L/L)

ip route 0.0.0.0 0.0.0.0 10.130.40.9 (M/W)

(L/L - leased line, M/W - microwave)

No change was made to the ip route for ISDN -

ip route 0.0.0.0 0.0.0.0 10.130.40.5 150

(10.130.40.5 is a loopback address at 3660 router)

[Richard Burts]

Lim

You had to make several changes on your 3660 including object tracking and local policy based routing to get the routes over the mmicrowave to fail and use the routes over the ISDN. Have you made similar changes on the 3640? My guess is that you have not made those changes and that even when the microwave is not working that the static route still points to the microwave on the 3640.

HTH

Rick

[pllim]

I did not know that I am suppose to make similar changes on the 3640.

I will have problem with if I need to do that because my IOS version is 12.2(10d) on the 3640. It does not support the feature. (I can create an RTR entry but will not be able to track it with my version)

[Richard Burts]

Lim

The 3640 is facing the issue that your 3660 faced which is that even if the microwave stops working and does not transmit data the Ethernet interface stays up and the routing still points to the Ethernet/microwave path. The optimum solution is what you have done on the 3660 with object tracking for static routes. If the 3640 is running a version that does not have this feature then there is a problem. An alternative to consider might be to run a dynamic routing protocol. The advantage of a routing protocol would be that it could detect when the microwave path was no longer transmitting data and could converge to use the ISDN. Or you could consider upgrading the version on the 3640 to a version that does have the feature of object tracking.

HTH

Rick

[pllim]

I don't have the new software version. I'll try to look around if I can find a new version for the 3640.