Re: Question about scenario requirements

A good thing to point on router-ids is that while you may creat the
habit of assinging router-ids that match the router designation
(1.1.1.1 for Router1, 2.2.2.2 for Router2, etc) is that on a NSSA OSPF
area the ABR with the greatest router-id is the one that is going to
make the 7-to-5 LSA translation, and following that "matching" rule
may interfere a requirement (for instance, you have routers 2 and 4 as
ABRs on a NSSA area, and the lab asks you that Router2 makes the
7-to-5 translation. In this case Router2's router-id needs to be
greater than Router4's.).

Persio

On Sat, Oct 10, 2009 at 11:21 AM, Larry Hadrava <larryh_at_ine.com> wrote:
> All have made valid points.
> One thing I might add.
> Do not just set the router-id for the technologies out of habit. Please take the time to KMOW and UNDERSTAND the WHY you are doing this. Play with it a few times for yourself to see the effects of adding a new loopback interface and reload the routers. Take the time to see it in action while you practice rather than just knowing about it and not knowing what it can cause - hint - troubleshooting;-) Know where to look and see in the show commands what the router-id is AND how it can cause routing to break in some complex routing environments that you see in the practice labs from the various vendors.
>
> Thanks
> --
> Larry Hadrava, Larryh_at_INE.com
> CCIE #12203 (R&S)
>
> Internetwork Expert, Inc.
> http://www.INE.com
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>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of Marko Milivojevic
> Sent: Saturday, October 10, 2009 8:06 AM
> To: Justin Mitchell
> Cc: Cisco certification
> Subject: Re: Question about scenario requirements
>
> One thing to be aware of are router-id's. Unless you are told not to
> do it, I would suggest you nail them to a know value. Otherwise, you
> may forget about them when new Loopback interfaces are created in
> subsequent tasks (i.e. BGP sections) and that's mayhem in disguise
> with things like virtual links and MPLS TE (for SP candidates). If you
> are told to let routers decide, carefully consider what will become
> router-id when device is reloaded and use that for all configurations.
>
> --
> Marko
> CCIE #18427 (SP)
> My network blog: http://cisco.markom.info/
>
> On Fri, Oct 9, 2009 at 10:39, Justin Mitchell <jgmitchell_at_gmail.com> wrote:
>> Reading through my materials and watching VoDs, I've picked up several
>> tips that seem to be very helpful until I start thinking about some of
>> the labs I have performed. How much extra configuration outside of the
>> "required" task is permitted?
>>
>> I am curious about using passive-interface default and assigning
>> router-ids. Sometimes in a lab it will say configure the process that
>> way, other times it doesn't say a thing. I'm assuming as long as
>> everything works in the end, that is all that matters, especially when
>> I think about the huge alias list I use.
>>
>> Thanks!
>>
>> Justin G. Mitchell
>> e: jgmitchell_at_gmail.com | skype: justin.g.mitchell
>>
>>
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Received on Sat Oct 10 2009 - 16:45:49 ART