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Switching from Frame Relay to ISDN backup

jpelletier
Level 1
Level 1

Hello to all. This may seem somewhat silly but I'll ask it anyways. We have a frame relay connection to each remote site backed up by ISDN. I have looked through the Cisco site and cannot find an answer-How do you switch over when your frame relay circuit fails? We don't want to roll over automatically.

6 Replies 6

jduffek
Level 1
Level 1

Why don't you want it to fail over automatically? If you want to do it manually then you could always change your routes when the problem happens or something like that.

Here is a some good docs on dial backup:

http://www.cisco.com/warp/public/123/backup-main.html

Josh

svermill
Level 4
Level 4

There is a command to delay bringing up the backup interface. On your primary interface:

router(config-if)#backup delay x y

x is how long before bringing up the backup and y is how long this interface must be back up before releasing the backup circuit once activated.

But DDR is really a better way to go. If you just use timers such as these, you end up placing a call after x, regardless of whether or not traffic is queued.

Thanks for the input, the reason I need to do it manually is because of the cost associated with ISDN, it's up to the remote office manager to use it. Do you have any info regarding the response from

the other respondents? Thanks again

mssearle
Level 1
Level 1

The general method for failover on frame-relay relies on floating static routes. However, if you want to do this manually you can always go with the suggestion to manually change the routes or you could have an alternative configuration stored on a local TFTP server relating to an ISDN configuration as the primary link. In this manner you can quickly lock down any extended amendments that would need to be made to ACLs to control interesting traffic and broadcasts. I take it that the reason you reauire manual intervention is down to the cost associated with ISDN? If so, and you are working in a small office then there is a simple solution to reduce costs overnight. Just buy a timer switch for your router plug and make sure it turns off automatically at night and turns on again in the morning. This should cost you about £5.

Thanks for the reply the help is great. If the primary goes down(frac T1), could I still telnet into the remote router to copy the back up ISDN config onto the router? Or could I do this from the TFTP location(main office)? Any help would be appreciated.

jpelletier
Level 1
Level 1

Josh thanks for replying, the reason we don't want to go over to backup automatically is that it's up to the remote office managers if they want to pay the cost of ISDN or just wait till the primary comes back up.