From: Yasir Zaman (yasirzaman2001@xxxxxxxx)
Date: Mon Jul 29 2002 - 05:34:13 GMT-3
In the First Instance you say that you cant use Bri with back Up Interface.You
can by making Dialer Interfaces and using one of the B Channels as usable and t
he Other as Back Up.
Yasir
----- Original Message -----
From: "kasturi cisco" <kasturi_cisco@hotmail.com>
Date: Thu, 25 Jul 2002 18:47:39 +0000
To: carlos@mnet.com.mx, ccielab@groupstudy.com
Subject: Re: [ospf demand vs. dialer-watch] when to use either
> Carlos,
>
> This is what i have undertsood as -
>
> When the scenario asks for a backup option there are 3 of them if its ISDN
> (assuming ISDN)
>
> 1. Backup interface command
> 2. Floating static routes
> 3. Dialer Watch
>
> -----------
>
> If u are allowed "backup option" then use 1.
> - But the downside is it cant monitor end-end connectivity (like FR PVC on
> Multipoint FR link),also if u are required to keep the BRI usable then this
> is not the option. Go to 2.
>
> 2. U may are may not be allowed Floating static routes..of course advantage
> is they are protocol independent.Here u need to ensure that the link is not
> kept up by the Hellos/broadcasts if the backup link comes up when using the
> static route (if used)
>
> 3.If lets say 1/2 are not allowed u can use Dialer watch. When u use dialer
> watch u need to ensure that the routing protcol does not keep the link up
> thru hellos/broadcasts otherwise the idle-timer does not expire and hence
> the Primary link wont be used effectively. To prevent this it depends on the
> protocol on the ISDN link which can be -
>
> say DV protcols ..use can use snapshot routing or deny ip any any
> say EIGRP ..deny EIGRP any any
> say OSPF...use IP ospf demand ckt or deny ospf any any.
>
> Am i correct ? someone correct me if i am wrong.
>
> HTH.
>
> kasturi.
>
>
>
>
> >From: "Carlos A. Silva" <carlos@mnet.com.mx>
> >Reply-To: "Carlos A. Silva" <carlos@mnet.com.mx>
> >To: "Ccielab" <ccielab@groupstudy.com>
> >Subject: [ospf demand vs. dialer-watch] when to use either
> >Date: Thu, 25 Jul 2002 10:58:15 -0700
> >
> >hi, all:
> >
> >right now i'm studying isdn for the exam and came across a scenario that
> >could be solved by using either.
> >the choice of using ospf-demand or dialer-watch is something that's not
> >that
> >clear to me right now and will depend on whatever
> >we get asked during the exam. i was wondering if anyone out there could
> >offer some assistance to figure out what would be
> >the better choice when asked to deploy a solution that could (apparently)
> >be
> >solved with either method.
> >
> >as far as i can tell the only difference is that ospf-demand would come up
> >whenever there's any change in the ospf
> >database and dialer-watch only when a (set of) route(s) gets lost. with
> >ospf-demand the ckt will go down as soon as the
> >database is updates (and there's no interesting traffic) while dialer-watch
> >will go down for brief periods of time, then check,
> >see that the lost route is still down and bring up the bri (you could say
> >bri will stay up as long as the route is lost).
> >
> >now, please bear in mind that i understand that these 2 features are not
> >the
> >same (functionally), but they could be used
> >to accomplish 'almost' the same thing in the exact same scenario.
> >
> >thoughts?
> >
> >regards,
> >carlos.
> >
> >Carlos A. Silva [tel]: 52.818.401.2191
> >Micronet de Mixico http://mnet.com.mx
> >
> >"...sal del camino, toma la ruta..." - Cerati
This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:36:47 GMT-3