From: kasturi cisco (kasturi_cisco@xxxxxxxxxxx)
Date: Tue Jul 30 2002 - 11:45:18 GMT-3
Ademola,
I dont think snapshot routing is backup mechanism. Is it bcoz it cant bring
the link up when primary is down ? i understand it as a mechanism to prevent
routes from Dv protocols constantly bringing up the demand ckt due to the
route-updates.
Let me know what others think ? the ohter 3 are backup mech.
Good luck,
kasturi.
>From: Ademola Osindero <osindero@lagos.sns.slb.com>
>Reply-To: Ademola Osindero <osindero@lagos.sns.slb.com>
>To: "Casey, Paul (6822)" <Paul.Casey@o2.com>,
>"'ccielab@groupstudy.com'" <ccielab@groupstudy.com>
>Subject: Re: Help please
>Date: Mon, 29 Jul 2002 14:15:53 +0100
>
>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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