Re: 3 OSPF non-zero areas

Anthony sir, I like your question of the day signature. :)

Jared, sir ..can we have only the question once more perhaps. ;)

On Thu, May 7, 2009 at 12:45 AM, Anthony Sequeira <
asequeira_at_internetworkexpert.com> wrote:

> "Towering genius disdains a beaten path. It seeks regions hitherto
> unexplored." Abraham Lincoln
>
> While Lincoln was not aware of the CCIE Lab Exam at the time, at least one
> 2 point task in every lab exam seeks to find "towering geniuses". :-)
>
> Great idea for the list Jared. But sadly, our longest threads will continue
> be about politics, race, and endless pontification regarding extremely
> subjective non-technical topics. Although, it certainly does add to the
> entertainment value of the list!
>
> Warmest Regards,
>
> Anthony J. Sequeira, CCIE #15626
> Senior CCIE Instructor
> http://www.InternetworkExpert.com
>
> Internetwork Expert, Inc.
> Toll Free: 877-224-8987
> Outside US: 775-826-4344
>
> Test your Core Knowledge today!
> Q: Examine the output below. What is the purpose of the Punt Adjacency in
> Cisco Express Forwarding?
> A: The Punt Adjacency is used when a packet is not capable of being handled
> by CEF on the Cisco device.
> More Info:
> http://www.cisco.com/en/US/docs/ios/12_1/switch/configuration/guide/xcdcef.html
>
>
> On May 6, 2009, at 2:38 PM, Jared Scrivener wrote:
>
> LOL. That's possibly the funniest (and unfortunately accurate) email I've
>> read in a few days. I hope this isn't my last 2 cents...
>>
>> The thing I find most ironically hilarious is that almost everyone here is
>> studying hard and paying hard earned cash for great materials from many of
>> the instructors/vendors in this forum, yet these simple little challenges
>> (which will probably teach everyone more in the space of one hour's
>> difficult thought than they'd gain from reading a book or doing a complex
>> lab for a day) don't gain much interest. I'll add that to my list of
>> curious
>> oddities...
>>
>> Cheers,
>>
>> Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP
>> Sr. Technical Instructor - IPexpert, Inc.
>> Telephone: +1.810.326.1444
>> Fax: +1.810.454.0130
>> Mailto: jscrivener_at_ipexpert.com
>>
>>
>> -----Original Message-----
>> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
>> Tony
>> Varriale
>> Sent: Wednesday, 6 May 2009 11:24 AM
>> To: 'Cisco certification'
>> Subject: RE: 3 OSPF non-zero areas
>>
>> Usually what occurs at this point is the original poster realizes that a
>> few
>> people have chimed in and it's got all it's gonna get. Then, the original
>> poster throws in their 2 cents and it goes into the archives.
>>
>> That's really how it worked in the old days.
>>
>> tv
>>
>> -----Original Message-----
>> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
>> Jared Scrivener
>> Sent: Wednesday, May 06, 2009 12:01 PM
>> To: smorris_at_internetworkexpert.com
>> Cc: 'Anthony Sequeira'; 'Roy Waterman'; 'Anantha Subramanian Natarajan';
>> 'Cisco certification'
>> Subject: RE: 3 OSPF non-zero areas
>>
>> Thanks, Scott. One of my mentors once told me to "think like a router" and
>> it was the best advice anyone ever gave me with respect to the CCIE.
>>
>>
>>
>> So, guys, I haven't seen any responses yet to my challenge question that
>> didn't involve changing the question (I didn't say you could add any more
>> tunnels). Back in the day (well, in the mid-late '90's when I was in high
>> school and writing under my 31337 identity - the good old days) it was
>> normal for highly technical engineers to post challenge questions to test
>> each other - in my opinion that's one of the reasons that that the old
>> "hackers" like Steve Wozniak got us to where we are now technologically.
>>
>>
>>
>> If I get some activity out of this I'd like us to consider doing more
>> "thought experiments" here on the list - you'll be amazed how much better
>> we
>> all become. Oh, I didn't say that I'd get the answer right either - so
>> don't
>> be afraid to be wrong. J
>>
>>
>>
>> Cheers,
>>
>>
>>
>> Jared Scrivener CCIE3 #16983 (R&S, Security, SP), CISSP
>>
>> Sr. Technical Instructor - IPexpert, Inc.
>>
>> Telephone: +1.810.326.1444
>>
>> Fax: +1.810.454.0130
>>
>> Mailto: <mailto:jscrivener_at_ipexpert.com> jscrivener_at_ipexpert.com
>>
>>
>>
>> From: Scott Morris [mailto:smorris_at_internetworkexpert.com]
>> Sent: Wednesday, 6 May 2009 3:49 AM
>> To: Jared Scrivener
>> Cc: Anthony Sequeira; Roy Waterman; Anantha Subramanian Natarajan; Cisco
>> certification
>> Subject: Re: 3 OSPF non-zero areas
>>
>>
>>
>> Jared's actually right on target with this method of thinking... As a
>> cool
>> way of studying (even though there's a plethora of variety between all the
>> vendors!) a candidate should be able to take any existing scenario and
>> start
>> thinking about "what if....?".
>>
>> Never fear to create your own modifications to things, or even your own
>> labs
>> for that matter. For years, I've been telling people to work towards
>> this.
>> The cool thing (as seen below) is that you'll end up creating some REALLY
>> ugly scenarios. But if you can think your way through them, you're doing
>> great on your comfort level with the technology!
>>
>> Don't fear making mistakes! Every once and a while, you will create/dream
>> an impossible scenario. Something that simply cannot happen. By the time
>> you've worked at it, thought about it, labbed at it and tried to make it
>> work, you have at least been spending time thinking about the protocol.
>> No
>> value is lost there.
>>
>> Any complicated task before you can be broken down into a series of simple
>> tasks. That level of visualization though, requires a lot of work! :)
>>
>>
>>
>>
>>
>> Scott Morris, CCIEx4 (R&S/ISP-Dial/Security/Service Provider) #4713,
>>
>> JNCIE-M #153, JNCIS-ER, CISSP, et al.
>>
>> JNCI-M, JNCI-ER
>>
>> smorris_at_internetworkexpert.com
>>
>>
>>
>> Internetwork Expert, Inc.
>>
>> http://www.InternetworkExpert.com
>>
>> Toll Free: 877-224-8987
>>
>> Outside US: 775-826-4344
>>
>>
>>
>> Knowledge is power.
>>
>> Power corrupts.
>>
>> Study hard and be Eeeeviiiil......
>>
>>
>>
>>
>> Jared Scrivener wrote:
>>
>> Every router has a connected route between them. Forget the numbered areas
>> -
>> Would the 3 contiguous GRE tunnels create a contiguous Area 0? I can't see
>> why not. From there it follows that every other router's numbered area
>> interfaces could be advertised into OSPF without incident (as if they were
>> loopbacks). This won't force the control plane path via the data plane
>> path
>> to build the control plane path (my description of tunnel recursion) as
>> the
>> numbered OSPF areas are going to be learned via OSPF with a Tunnel
>> interface
>> next hop (which is fine) and the GRE packets that carry the OSPF packets
>> will be routed via the connected routes as each GRE packet is going over a
>> single hop to a directly connected neighbor.
>>
>> A more difficult question (here's a gauntlet thrown down) is what would
>> happen if there was an area router in the middle of each area (between R1
>> and R2, R2 and R3 etc)? Please don't lab this up and paste the configs
>> until
>> everyone has a chance to visualize and discuss this (explain your
>> reasoning
>> from first principles). It's a great thought experiment so pick an answer
>> THEN prove it on hardware (if you can visualize this, you can do anything
>> -
>> this kind if puzzle is as hard as it gets).
>>
>> Game on. :)
>>
>> Cheers,
>>
>> Jared
>>
>> PS If you see three numbered areas and can't create area zero you can
>> redistribute each area into the adjacent one other by putting them in
>> separate processes (ASBRs and no ABRs). No need for tunnels (the least
>> preferable method). Redistributing between multiple processes should be
>> your
>> second preferred method (VLs between routers and adding a loopback in Area
>> 0
>> is method number one of course, if allowed).
>>
>>
>> On May 5, 2009, at 10:28 PM, Anthony Sequeira
>> <mailto:asequeira_at_internetworkexpert.com> <
>> asequeira_at_internetworkexpert.com>
>> wrote:
>>
>>
>>
>>
>> I think Anantha is really going "outside the box" here as he has NO area 0
>> at all.
>>
>> It is really late for me, but I am thinking the only time we can go
>> without
>> an Area 0 in OSPF is when we only have a single area.
>>
>> Warmest Regards,
>>
>> Anthony J. Sequeira, CCIE #15626
>> Senior CCIE Instructor
>> http://www.InternetworkExpert.com
>>
>> Internetwork Expert, Inc.
>> Toll Free: 877-224-8987
>> Outside US: 775-826-4344
>>
>> Test your Core Knowledge today!
>> Q: What is the BGP synchronization rule?
>> A: This rule states that a router will not use or advertise a route
>> learned
>> by IBGP until a matching route has been learned from an IGP.
>> More Info:
>>
>> www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfbgp.html#wp10029
>> 10
>>
>> On May 6, 2009, at 1:01 AM, Roy Waterman wrote:
>>
>>
>>
>>
>> Sorry what i meant to say was:
>>
>> You can create a virtual link to extend area 0 to area 4, and then create
>> a
>> 2nd virtual link to extend area 0 (which was extended to area 4) to area
>> 5.
>>
>> 2009/5/6 Roy Waterman <mailto:roy.waterman_at_gmail.com>
>> <roy.waterman_at_gmail.com>
>>
>>
>>
>>
>> Hi Anantha
>> You can create a virtual link to extend area 0 to area 4, and then create
>> a
>> 2nd virtual link to extend area4 to area 5.
>>
>>
>> 2009/5/6 Anantha Subramanian Natarajan
>> <mailto:anantha.natarajan_at_gravitant.com> <anantha.natarajan_at_gravitant.com
>> >
>>
>> Hi All,
>>
>>
>>
>>
>> Is it possible to run OSPF when there are three OSPF areas as shown below
>> and none of them is not a area 0.
>>
>> R1 --ospf area3 --R2 ---ospf area4 ---R3 ----ospf area5 --R4
>>
>> My understanding is that, virtual-link would be only useful when to join a
>> non-zero area to connect to area0 which is seperated by another
>> non-zero area.Also the virtual links would be useful in case where area 0
>> is
>> broken in between a non-zero area.Assuming my above understanding is
>> right,I
>> am thinking the above scenario will not be able to use virtual links to
>> propagate OSPF routes among R1,R2,R3,R4.
>>
>> In this case,if I would be able to build GRE tunnel between
>> R1-R2,R2-R3,R3-R4 and run OSPF on area0 over them,In that case,will the
>> OSPF
>> routes would be able to get propagated ?
>>
>> Thanks for the help
>>
>> Regards
>> Anantha Subramanian Natarajan
>>
>>
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>>
>> --
>> Regards
>> Roy
>>
>>
>>
>>
>> --
>> Regards
>> Roy
>>
>>
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