Hi Everyone, I need to configure a ISDN link as backup for the primary interface. The primary interface is Ethernet1. I researched a numbers of books and they all are talk about serial or frame relay interface as the primary. I was able to search the archives and I found the identical problem that I am encountering. The post stated that yes the BRI0 interface can work as a backup for an ethernet interface. The following is a paste of the post(by Howard Berkowitz): "Yes. The key to the solution is to use a low-overhead routing protocol such as OSPF or EIGRP as a layer 3 keepalive mechanism." "Set up OSPF or EIGRP to define a path to the destination using the Ethernet. Set up a static route with administrative distance greater than that of the routing protocol (at least 200 is a good idea), with this static route going to the next hop address of the remote ISDN interface. If OSPF or EIGRP stop seeing hellos across the Ethernet, they will drop the route. The static route will now float up into the routing table, and you will get dial-on-demand routing across the ISDN. When OSPF sees its route again, after the Ethernet is back up, the Ethernet route will replace the ISDN in the active routing table, and the inactivity timer on the ISDN will disconnect it." I have followed the instructions, but no luck. When I shutdown the ethernet interface the BRI0 backup interface will not come up. The question I have are: 1. If I administratively shutdown the ethernet interface is that the same as if I disconnected the cable so that the e1 interface will not see a keepalive. 2. I did not see any other treads as to if solution worked. Has anyone run into this situation and has an answer or suggest anything. My config: interface Ethernet1 backup delay 0 3 backup interface BRI0 router eigrp 10 network 172.26.0.0 ip route 172.20.20.0 255.255.255.0 10.10.9.5 200 Lastly, one of the books (Internetworking & Troubleshooting by C. Long) stated something about layer 2 and the "no keepalive" option. It didn't go further on this issue and don't know if I understood it. If someone can explain, it would be much appreciated. Sorry for the long post. TIA KM _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=7027&t=7027 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]