From: Krake, Kris (KKrake@xxxxxxxxxxxx)
Date: Thu Jul 25 2002 - 15:25:55 GMT-3
If the requirements said make sure that ISDN *only* comes up when the
primary link fails I would think that dialer-watch would be more
appropriate. I'm just making a stab at this so anyone feel free to correct
me as I've wondered this myself but:
Would demand circuit be inappropriate for those requirements as it would
come up whenever there was a change in the OSPF database...not necessarily
the primary link? In a stable environment to me they would be similar but
if you should happen to have a route flapping *somewhere* other than the
primary link this would break the constraints wouldn't it?
Thoughts?
Kris
-----Original Message-----
From: Carlos A. Silva [mailto:carlos@mnet.com.mx]
Sent: Thursday, July 25, 2002 1:58 PM
To: Ccielab
Subject: [ospf demand vs. dialer-watch] when to use either
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
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