Failover using p2p T1, 2 buildings with inet connections

Discussion in 'Cisco' started by mike240se, Nov 15, 2008.

  1. mike240se


    Nov 15, 2008
    Hi, I have been trying to setup a fairly simple sounding setup for quite some time without much luck. I have researched this and found some ways that could work, but nothing exactly like my situation.

    basically, i have 2 buildings, each building has its own internet connection, a cable modem service that uses dynamic dhcp (it rarely changes ip's but it can). Then i have a Point to Point T1 Line connected between these 2 buildings.

    I would like to have it so if one of the internet connections goes down, that building then gets its internet from the other buildings internet connection, over the T1.

    I have 4 cisco routers. The t1 is connected on both sides with 1721's with DSU's. The internet is connected with their own 1721's with WIC-ENET cards.

    I am currently using RIP V2, but it just doesnt work right. I believe IP SLA is partly what i need, possibly OSPF. But i think there is an issue that my internet connections are dynamic dhcp. So i cant just switch metrics on static default routes using ip sla. Basically today, default route on router 1 may be and next month it could be

    I read something aobut optimized edge routing first, but am not sure if this is exactly right or not. Router hot standby protocol will not work since these are seperate networks (192.168.0.x and 192.168.1.x, conncted by 172.16.0.x t1 network)

    I would appreciate all and any help. This has been driving me nuts!

    EDIT: Just want to add a couple things i forgot, both of the inet connection routers use NAT to supply access to their buildings. Also I made a typo, one of the inet routers is a 851, not a 1721. It doesnt support the track command, which could be a problem i think.

    I tried using this a little:

    cisco reliable routing using object tracking (sorry i cant post the link cause of forum rules)

    but its not really what i want, but close.

    Also, the default route my router gets from the cable ISP, is listed as static but with an AD of 254. Maybe this is part of the problem? When the link goes back up, the rip default route is not replaced, i have to do a clear ip route, maybe that is because the AD is 254 and so rip is lower and therefore wouldnt be replaced?
    Last edited: Nov 16, 2008
    mike240se, Nov 15, 2008
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