From: talbotpat@xxxxxxx
Date: Sun Apr 07 2002 - 23:40:07 GMT-3
> From: "Howard C. Berkowitz" <hcb@gettcomm.com>
> Date: 2002/04/07 Sun PM 08:23:39 EDT
> To: ccielab@groupstudy.com
> Subject: Statics, defaults, and the lab
>
> I've been working on a practice scenario, involving, among many other
> things, RIP-OSPF mutual redistribution. My challenge is that I wanted
> to do something that is real-world good practice: standardizing on
> loop0 interface addresses that are /32, postulating the customer
> would eventually transition completely to OSPF.
>
> The challenge is how to ping discontiguous /32's in a RIP network. In
> principle, it's not something RIPv1 can do. If this were the real
> world, I could solve this trivially with a couple of static and
> default routes. I can make it work under some fairly bizarre
> constraints, like using extended ping to force a source address to
> which has a return path.
>
> To do what I want to do with routing, however, the alternatives are
> so bizarre that I wonder if it's beyond what conceivably could be on
> the test. Now, this is NOT a request for NDA information, but it's
> my impression from Solie and various CCIE power sessions that the lab
> scenarios NEVER use static or default routes. Am I correct here, or
> is "NEVER" really "HARDLY EVER"?
Don't know for sure as I will visit the lab for the first time May 18, but I'm
pretty sure that your impression is correct. All practice labs and prep materi
als that I have seen and everything I have heard and/or read would seem to back
that up. But I guess anything is possible in the real thing.
>
> Let's see...some of the ways I've hacked it:
>
> 1. Implement policy routing and set default interface.
> 2. Use BGP as an intermediate protocol between RIP and OSPF so I
> can use conditional default advertisement
>
An intermediate routing process has been discussed to solve other redistributio
n issues as well, I think (and hope) this is an acceptable approach on the lab
exam.
> OSPF default-information originate doesn't fit the bill, because I
> have two redistribution points. If I had one redistribution point, I
> could, in good conscience, do default-information originate always,
> because the traffic would blackhole. But with two points of
> redistribution, I want default originated only if the point of
> redistribution indeed can act as a default router.
>
> BGP conditional advertisement would do what I want. If I could put a
> default route into the OSPF router, and control default origination
> by the reachability of the next hop of the default route, I could
> also make it work. The OSPF router really wouldn't use the default
> route other than as a control mechanism for default information
> originate.
>
> Am I simply creating a situation that is outside the reasonable scope
> of the lab?
God I hope so.... ;-)
>
> This scenario and others, incidentally, will be available for free
> noncommercial use from Gettlabs, but we need to work out some server
> issues that I hope will be done in the next couple of days. It's too
> long to post here.
> --
> "What Problem are you trying to solve?"
> ***send Cisco questions to the list, so all can benefit -- not
> directly to me***
> *****************************************************************************
***
> Howard C. Berkowitz hcb@gettcomm.com
> Chief Technology Officer, GettLab/Gett Communications http://www.gettlabs.com
> Technical Director, CertificationZone.com http://www.certificationzone.com
> "retired" Certified Cisco Systems Instructor (CID) #93005
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