From: Ademola Osindero (osindero@xxxxxxxxxxxxxxxxx)
Date: Mon Jul 29 2002 - 10:15:53 GMT-3
Paul,
You have four choices for implementing ISDN backup
Interface Backup
Dialer Watch
Snapshot Routing
Floating Static
You can implement any of this with the access-list 120 deny eigrp any any
for the dialer-list except for Snapshot routing. If you put an interface as
passive and expect to run eigrp over it using the neighbor command, it will
not work. You don't need interafce backup and dialer watch together, try
use dialer watch only. Floating static route may be surest bet, you make
the route choice less preferable and left constantly watching but you will
definitely need to deny eigrp under the access-list. Denying eigrp on the
access-list does not infer that eigrp routes will not pass over the link
but that eigrp routes will only be passed over it if other ip packets
initializes the link.
Give them all a shot and let's see what we've got. (To be frank, I setup
dialer watch for OSPF and it didn't work. Why? I haven't checked that yet).
Ademola
PS One more thing, I am sure you can influence an eigrp route choice with
MTU and reliabilty as well cos they are part of the calculation.
At 09:36 AM 7/29/2002 +0100, Casey, Paul (6822) wrote:
>A question,
>
>I have a 2 routers, connected back to back with serial connection, and
>running eigrp and advertising local routes on both sides. No problems so
>far.
>I also have an ISDN line between the 2 routers, and the bandwidth and delay
>on the link is to be set to the same as the serial interface, also EIGRP is
>to be run on the interfaces.... Again no problems.. The route should show up
>with 2 possiberl paths, in the routing table, ..... becuase of the same
>bandwidth and delay.
>
>Now here's where the problem starts,
>EIGRP is not to keep the ISDN up..
>Also when the serial link is active the router should prefer that link over
>the ISDN link...remember bandwidth and delay are set to be the same.
>
>Now the problem here is that if I use passive interface on the isdn link the
>routes are removed from the routing table, over the ISDN link and EIGRP
>doesn't see it as a possible path, and when you pull, out on side of the
>serial link, The router cant route to the other side because passive
>interfaces has stopped the hello's and the neighbor formation.
>
>But I dont see any other way of stopping eigrp from bring up the link...???
>
>I have tried using backup interface, with dialer-watch and not using
>passive-interface bri0 and this works fine.. no problems.. however for
>reading the case seceniro, you are not supposed to put the isdn as a backup
>interface as the router is supposed PERFER the serial link when both links
>are working.
>
>Also I could use an access-list with the dialer-list, and deny eigrp, but
>then no routing info would pass over the isdn link either, as far as I know.
>
>I am confused as how you are expected to maintain the routes over isdn, and
>at the same time stop eigrp from bringing up the link..
>
>
>Any help appreciated
>kind regards.
>
>Paul..
>
>
>
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