From: Tarun Pahuja (pahujat@gmail.com)
Date: Wed Oct 24 2007 - 06:25:37 ART
Slight correction, Math says that if you have 5 possible combinations, the
possible number of combinations would be n(n-1)/2. Therefore, The possible
ways would have been 10 and not 15(in which one could try to form adjacency
).
5X(5-1)/2 = 10
Thanks,
Tarun Pahuja
CCIE#7707(R&S,Security,SP,Voice,Storage),CCSI
On 10/23/07, Scott Morris <smorris@ipexpert.com> wrote:
>
> hehehehe... Yes, the response was a joke. (sort of)
>
> There are indeed 15 ways to combine those network types, math doesn't
> lie. No, all of them will not work together.
>
> However, that's the point of learning is it not? If you are interested in
> finding some document which may or may not contain all the possibilities and
> memorize it, go ahead. If you are interested in trying something out and
> attempting to learn WHY it will or will not work, you'll have much better
> retention of knowledge and depth of knowledge at that point.
>
> The second path will take a little longer, but the long-term reward is
> much greater.
>
> "Any fool can know. The point is to understand." -- Albert Einstein
>
>
> Scott Morris, *CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713,
> JNCIE-M #153**, JNCIS-ER, CISSP, et al.*
> *CCSI/JNCI-M/JNCI-ER*
> VP - Technical Training - IPexpert, Inc.
> IPexpert Sr. Technical Instructor
>
> A Cisco Learning Partner - We Accept Learning Credits!
>
> smorris@ipexpert.com
>
> Telephone: +1.810.326.1444
> Fax: +1.810.454.0130
> http://www.ipexpert.com
> ------------------------------
> *From:* Tarun Pahuja [mailto:pahujat@gmail.com]
> *Sent:* Tuesday, October 23, 2007 4:15 AM
> *To:* Scott Morris
> *Cc:* Joseph Brunner; Ananth Vk; ccielab@groupstudy.com
> *Subject:* Re: Query : Network Types
>
>
> Scott,
> I hope your last response was not a Joke ;-) I know you like to
> joke sometimes........
>
> There are 5 different type of network types under ospf namely:
>
> 1. broadcast
> 2. non-broadcast
> 3. point-to-point
> 4. point-to-multipoint
> 5. point-to-multipoint non-broadcast
>
> One can not simply use 5+4+3+2+1 logic or any other mathematical logic to
> figure out what possible combinations are possible. Every network type under
> ospf has certain characteristics(DR/BDR,Hello,Dead interval,etc). For ospf
> to form adjacency with neighbors certain conditions must be met or else no
> relationship would be formed. Additionally, as per Cisco Routing and
> Switching official exam guide, it is not recommended to form neighbor
> relationship between ospf network types requiring a DR/BDR and network types
> that do not require a DR/BDR in NBMA networks even though the neighbor
> relation comes up after fine tuning the Hello/Dead intervals.
>
> http://books.google.com/books?id=dKzpj4r7KCwC&pg=PA270&lpg=PA270&dq=nbma+ospf+network+type&source=web&ots=qLxQS3ST7M&sig=VpZJ06-c7z-fn6wz4MPb8Ocwk-U
>
>
> HTH,
> Tarun Pahuja
> CCIE#7707(R&S,Security,SP,Voice,Storage),CCSI
>
>
>
>
>
> On 10/22/07, Scott Morris <smorris@ipexpert.com> wrote:
> >
> > It's just math. 5+4+3+2+1 I didn't spend any time thinking more about
> > what
> > things would/wouldn't change. That's the part about studying. :)
> >
> > -----Original Message-----
> > From: Joseph Brunner [mailto:joe@affirmedsystems.com]
> > Sent: Monday, October 22, 2007 10:45 AM
> > To: 'Scott Morris'; 'Ananth Vk'; ccielab@groupstudy.com
> > Subject: RE: Query : Network Types
> >
> > Scott is that 15 number including when we use 2 network types that
> > do/don't
> > require a dr and change the timers?
> >
> > -Joe
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > Scott Morris
> > Sent: Monday, October 22, 2007 10:20 AM
> > To: 'Ananth Vk'; ccielab@groupstudy.com
> > Subject: RE: Query : Network Types
> >
> > As long as you have labbed those up and SEEN how things work, you'll
> > have no
> > worry about the order or combination or anything.
> >
> > There are 5 network types:
> >
> > 1. broadcast
> > 2. non-broadcast
> > 3. point-to-point
> > 4. point-to-multipoint
> > 5. point-to-multipoint non-broadcast
> >
> > If you are aware of the details of each, you'll be
> > fine. Mathematically,
> > there are 15 different combinations you can come up with.
> >
> > HTH,
> >
> >
> > Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713,
> > JNCIE-M
> > #153, JNCIS-ER, CISSP, et al.
> > CCSI/JNCI-M/JNCI-ER
> > VP - Technical Training - IPexpert, Inc.
> > IPexpert Sr. Technical Instructor
> >
> > A Cisco Learning Partner - We Accept Learning Credits!
> >
> > smorris@ipexpert.com
> >
> > Telephone: +1.810.326.1444
> > Fax: +1.810.454.0130
> > http://www.ipexpert.com
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > Ananth Vk
> > Sent: Monday, October 22, 2007 5:31 AM
> > To: ccielab@groupstudy.com
> > Subject: Query : Network Types
> >
> > Hi
> >
> > I just wanted to confirm that these are the following network types
> > regardless of layer 3 protocol
> >
> > 1. point to point - serial point to point links
> >
> > 2. broadcast - lan
> >
> > 3. NBMA (FR/ATM/etc)
> >
> > A. Pure Point-to-Point Configuration (each VC on a separate
> > subinterface)
> >
> > B. Pure Multipoint Configuration (no subinterfaces)
> >
> > C. Hybrid Configuration (point-to-point and multipoint subinterfaces)
> >
> > I got this from a cisco link, is this the right order/fashion that i
> > should
> > remember / is there a different perspective ?
> >
> > Pls advice !
> >
> >
> > Thanks
> > Ananth
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