The "science" of subnetting is the easy part; it is simple binary math.
_Efficiently_ using your allocated addresses with _summarization_ while
allowing for _expansion_ is an art. The problem is there any many people
(including myself) who are classified as "knowing enough to be dangerous".
My problem is that all the books I read use private addreses and dumbed-down
"real-world" case studies. Personally, I have also been spoiled with 10
networks...
Here are some suggestions I have come up with:
1. Allow room for expansion (this is tricky, because you have to efficiently
use space to ask for more).
2. Allow room above and below subnets where possible.
3. Plan for growth: map out potential additions according to location,
business unit, or whatever hierarchy works for you.
4. Keep /30s close to to subnets they are connecting (for IGPs, not stub
networks), focus on summarization.
5. Get ready to move stuff around as you learn.
Thanks for the replies and good discussion. I knew how to subnet the first
day I learned about it (CCNA days), but I've become better after having to
use it in real-world situations. If I was going to hire someone, I would
focus on their design methodology, not on how well they could do everything
without a calculator or spreadsheet.
"Advanced IP Network Design" - Cisco Press CCIE Professional Development
touches on most of these issues, with case studies. It would have helped me
more if I wasn't reading so many other books (BGP, SONET, MPLS, VoIP, OPSF,
etc.) :)
John
----- Original Message -----
From: "dad" <[EMAIL PROTECTED]>
To: "John Deatherage" <[EMAIL PROTECTED]>
Sent: Monday, September 25, 2000 5:16 PM
Subject: Re: art of subnetting
> Subnetting is no art, but a Science. It works by the same rules
everytime.
> Just as any IP network has a Broadcast, a Wire and several host; so do
> subnets. A network exist to allow 2 or more host to communicate, each
with
> a unique address. The range of addresses is goverened by the subnet mask.
A
> mask basically moves the classfull boundary. So a network DOES not
connect
> seperate subnets as you say. It connects host on the same subnet. A /30
has
> 4 addresses ,2 host addresses and a broadcast and a wire. making its use
> very speciffic- Point to Point connectivity. A /20 has 12 bits for host
> addresses, making 4096 host addresses available -2
>
> Not sure where this would a good choice,
>
> Anyway, Hope this helps !
>
> 44
> -----Original Message-----
> From: John Deatherage <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> Date: Saturday, September 23, 2000 12:10 AM
> Subject: art of subnetting
>
>
> >Here is my dilemna: I could probably answer most questions on CCNP, CCIE
> >written, etc. exams on subnetting, but the most important thing seems to
be
> >real-world experience. I'm mainly looking for more info on the following
> >topics:
> >
> >- /30 for wan links, when/where to use
> >- if you have a /20 (example), where to put your blocks (of course,
> >summarization is a must), and where it's generally better to put /30s
> >according to what two subnets they are connecting
> >
> >All I can really do is look over case studies and real-world examples
that
> >people show me, and learn from my mistakes. I just want to be able to
> >design IP networks and be able to show the results to someone and not
leave
> >any room for improvement ;)
> >
> >John
> >
> >**NOTE: New CCNA/CCDA List has been formed. For more information go to
> >http://www.groupstudy.com/list/Associates.html
> >_________________________________
> >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
> >FAQ, list archives, and subscription info: http://www.groupstudy.com
> >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
>
**NOTE: New CCNA/CCDA List has been formed. For more information go to
http://www.groupstudy.com/list/Associates.html
_________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
