From: Joe Soricelli (jsoricelli@xxxxxxxx)
Date: Tue May 25 1999 - 01:40:02 GMT-3
All:
Starting with 11.3 configuring a loopback interface with the ip ospf network
point-to-point command will cause the router to advertise that address as
the configured subnet route and NOT a /32 route as in previous IOS versions.
Doyle footnote page 417.
-joe
-----Original Message-----
From: Ben Rife <brife@bignet.net>
To: Scott Morris <SMorris@tele-tech.com>; 'Nentarz, Dave'
<Dave.Nentarz@compaq.com>; 'Brian Van Benschoten'
<brian.vanbenschoten@inacom-msn.com>; ccielab@groupstudy.com
<ccielab@groupstudy.com>
Date: Monday, May 24, 1999 9:22 PM
Subject: Re: OSPF and virtual links
>53 days left for me....
>
>To answer the original question
>I would go ahead and configure L0... interfaces because of the stability
>involved. You may also have to run BGP on a router which is also running
>OSPF, in this case, I definitely would want to use L0.. interfaces. I have
>found that the advantages outweigh the disadvantages in my studies.
>
>About the "ip ospf net point" comand:
>
>Actually from my studies, this command.....ip ospf network point-to-point
>is used when doing OSPF over Frame, because there is a problem with
>mismatched network types (i.e., timers).
>
>For example, when OSPF is configured on Ethernet, the network type is
>BROADCAST, when OSPF is configured on an NBMA interface, the type is
>non-broadcast, etc.
>
>This creates a problem when setting up OSPF, the solution is to make all
>OSPF interfaces the same.
>I prefer to make all of my OSPF interfaces BROADCAST type. This is done
>with the interface configuration command: ip ospf network broadcast.
>
>Hope this helps, If you would like to discuss this further, let me know.
>Caslow's BRS book does a great job of explaining this.
>
>Regards,
>Benjy Rife
>MCSE, CNE, CCIE Candidate
>brife@bignet.net
>
>----- Original Message -----
>From: Scott Morris <SMorris@tele-tech.com>
>To: 'Nentarz, Dave' <Dave.Nentarz@compaq.com>; 'Brian Van Benschoten'
><brian.vanbenschoten@inacom-msn.com>; <ccielab@groupstudy.com>
>Sent: Monday, May 24, 1999 7:11 PM
>Subject: RE: OSPF and virtual links
>
>
>> Ummmm.... All that statement does (as far as i'm aware) is change the
>> timers of the OSPF process on that interface... If you want to advertise
>a
>> loopback any way other than /32, you'll need to do redistribute
connected,
>> and possibly use a route map to pull that route through (ie. don't add
>that
>> network directly into the OSPF process).
>>
>> Scott Morris, MCSE, CNE (3.x), CCDA, CCIE #4713
>> smorris@tele-tech.com
>>
>>
>> -----Original Message-----
>> From: Nentarz, Dave [mailto:Dave.Nentarz@compaq.com]
>> Sent: Monday, May 24, 1999 10:20 AM
>> To: 'Brian Van Benschoten'; ccielab@groupstudy.com
>> Subject: RE: OSPF and virtual links
>>
>>
>> I remember seeing a tech tip regarding this.
>>
>> Configure this under (loopback) interface mode:
>> ip ospf network point-to-point
>>
>> This will make OSPF advertise your loopback interface as the network or
>> subnet it's mask defines, rather than the /32 host route.
>>
>> I tried searching CCO docs for this to find which IOS level this first
>> appeared in as a feature, but couldn't find anything on it..I'll keep
>> looking.. try it in your lab and let me know if it works.
>>
>> Dave
>>
>> -----Original Message-----
>> From: Brian Van Benschoten [mailto: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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