From: Cromer, Darren (CAP, CFS) (Darren.Cromer@xxxxxxxxxxxxx)
Date: Mon May 24 1999 - 11:14:48 GMT-3
Brian,
I wouldnt get to bent out of shape over this. The answer to your question
really depends on which lab you get. Remember you can ask the lab proctor
any question you want (don't over do it though and be concise). You may not
get an answer, or you may get a vague answer, although even the vague
answers helped me out quite a bit. I would think though that depending on
the lab test you get, the proctor would be willing to answer this one for
you.
btw, you are correct, you build virtual links via the router id, which may
have been established via a loopback. Using the technique of loopbacks to
establish routers id's however, does not create the requirement that your
loopbacks be announced via ospf. If the loopback is not accessable, the
router, using its ospf database will access the router using a real,
announced interface.
Darren Cromer
Integration Engineer, CCIE #4384
(513) 459-6596
email: dcromer@sarcom.com
email: darren.cromer@gecapital.com
> -----Original Message-----
> From: Brian Van Benschoten [SMTP:brian.vanbenschoten@inacom-msn.com]
> Sent: Sunday, May 23, 1999 12:55 PM
> To: ccielab@groupstudy.com
> Subject: OSPF and virtual links
>
> I set up a lab test using virtual links. I used loopback interfaces (
> with
> high ip numbers) on both the routers that the vitural link connected. I
> did
> this for stability and the fact the one of the routers had an ISDN dial
> backup link with a higher IP address than the other interaces. This is
> the
> method most people recommend to do in the field. I realized that the
> loopbacks must be reachable from both routers in order to establish the
> virtual link. (the virtual link command points to the ROUTER ID, not an
> interface) so i included the loopbacks in the routing protocol. This got
> me
> thinking about the CCIE lab
>
> A question regarding the CCIE lab exam..... I've had people tell me not
> to
> do anything extra / more than is asked for during the lab. People have
> told
> me that at the end of a section where different ip routing protocols /
> redistribution are used, all routers should be able to ping all other
> interfaces. Does this mean the "extra" interfaces i created to do a task
> ?
>
> If i include my loopback interfaces in whatever area my router is in,
> using
> the network command; OSPF advertises loopback interfaces as /32. This
> mask
> wont redistribute into classfull routing protocols like IGRP. I could run
> the loopbacks in a seperate area an use the "area range" to summarize
> those
> addresses to match whatever subnet nask the classful protocol needed. But
> then am I supposed to create more OSPF areas than what the lab required ?
> I
> could redistribute connected into OSPF but then the routes show up as
> external ?
>
> anyone see where I'm going with this ? Any opinions?
>
>
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