Please Whitelist This Site?

I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)

If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.

If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK.

Thanks for your understanding!

Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide


NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.

The Book is Here... and Now On Sale!

Get The TCP/IP Guide for your own computer.
The TCP/IP Guide

Custom Search







Table Of Contents  The TCP/IP Guide
 9  TCP/IP Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)
      9  TCP/IP Internet Layer (OSI Network Layer) Protocols
           9  Internet Protocol (IP/IPv4, IPng/IPv6) and IP-Related Protocols (IP NAT, IPSec, Mobile IP)
                9  Internet Protocol Version 4 (IP, IPv4)
                     9  IP Addressing
                          9  IP Subnetting: Practical Subnet Design and Address Determination Example

Previous Topic/Section
IP Subnetting: Practical Subnet Design and Address Determination Example
Previous Page
Pages in Current Topic/Section
1
2
Next Page
IP Subnetting Step #2: The Key Design Trade-off: Partitioning Network Address Host Bits
Next Topic/Section

IP Subnetting Step #1: Requirements Analysis
(Page 1 of 2)

When you are building or upgrading a network as a whole, the first step isn't buying hardware, or figuring out protocols, or even design. It's requirements analysis, the process of determining what it is the network needs to do. Without this foundation, you risk implementing a network that may perfectly match your design—but not meet the needs of your organization. The exact same rule applies to subnetting as well. Before we look at the gory details of host addresses and subnet masks, we must decide how to subnet the network. To do that, we must understand the requirements of the network.

Key Subnetting Requirements

Analyzing the requirements of the network for subnetting isn't difficult, because there are only a few issues that we need to consider. Since requirements analysis is usually done by asking questions, here's a list of the most important questions in analyzing subnetting requirements:

  • What class is our IP address block?

  • How many physical subnets are on the network today? (A “physical subnet” generally refers to a broadcast domain on a LAN; a set of hosts on a physical network bounded by routers.)

  • Do we anticipate adding any more physical networks in the near future, and if so, how many?

  • How many hosts do we have in the largest of our subnets today?

  • How many hosts do we anticipate having in the largest subnet in the near future?

The first question is important because everything in subnetting is based around dividing up a Class A, Class B or Class C network, so we need to know which we are dealing with. If we are in the process of designing a network from scratch and don't have a Class A, B or C block yet, then we will determine which we need based on the approximate size of the organization. After that, we need to determine two key numbers: how many physical subnets we have, and the maximum number of hosts per subnet.


Previous Topic/Section
IP Subnetting: Practical Subnet Design and Address Determination Example
Previous Page
Pages in Current Topic/Section
1
2
Next Page
IP Subnetting Step #2: The Key Design Trade-off: Partitioning Network Address Host Bits
Next Topic/Section

If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $



Home - Table Of Contents - Contact Us

The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005

© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.