From: Christian Sica (csica@liweb.net)
Date: Tue Dec 27 2005 - 15:00:45 GMT-3
I don't see how using the "ip ospf demand-circuit" feature will help you
here. This command was designed to allow an OSPF adjacency to remain up
without sending constant hello packets out the interface. This was usefull
for ISDN since it would allow the neighborship to form over the ISDN link
without keeping the ISDN circuit up. I would suggest you look at the
"backup" feature. Look at the wording, "Configure the network in such a way
that this link is only used if R4 (a spoke) loses its connection to the
frame-relay cloud." So, if you just set the cost of the PPP link to say
1000, does that meet the requirements? Is that enough to prevent any
traffic from using the circuit unless the frame circuit is down? Try it
out.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gustavo Novais
Sent: Tuesday, December 27, 2005 9:54 AM
To: Chula Bandara; Cisco certification
Subject: RE: Other ways of solving it --- frame-relay backup
Yes,
I think that both of them (increasing cost and demand-circuit) must be used.
Increase cost because we do not wish the circuit to be used, and Demand
Circuit to suppress hellos, and then effectively we do NOT use the ppp link.
I think that either of those used by its own would not guarantee that you
would not use the ppp link (unless FR goes down on R4)
Gustavo Novais
________________________________
From: Chula Bandara [mailto:chula_bandara@hotmail.com]
Sent: terga-feira, 27 de Dezembro de 2005 14:48
To: Gustavo Novais
Subject: RE: Other ways of solving it --- frame-relay backup
I think , you can also do a ip ospf demand-circuit over a point-to-point
circuit.
________________________________
From: "Gustavo Novais" <gustavo.novais@novabase.pt>
Reply-To: "Gustavo Novais" <gustavo.novais@novabase.pt>
To: "Cisco certification " <ccielab@groupstudy.com>
Subject: Other ways of solving it --- frame-relay backup
Date: Tue, 27 Dec 2005 14:27:18 -0000
Hello group,
I have a task where I'm asked to do a backup of a frame-relay
circuit
using OSPF. The backup line is a dedicated serial line encapsulated
with
ppp. The wording is as follow:
Configure area 0 on the ppp link between R4 and R5
The ppp link will be a backup of of frame-relay connection between
R4
and R5 (both using major interfaces, R5 hub, R4 spoke). Configure
the
network in such a way that this link is only used if R4 (a spoke)
loses
its connection to the frame-relay cloud.
My obvious solution to this is just to increase the ospf cost of the
interfaces involved on the ppp link, in order that it does not show
up
as the preferred path between R4 and R5.
My doubt is that perhaps this solution may be too obvious, and
perhaps I
am missing something...
Any suggestions or alternative ways of doing this? Am I just being
paranoid about complexity?
Thank you
Gustavo Novais
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