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 Classless Addressing: Classless Inter-Domain Routing (CIDR) / "Supernetting"

Previous Topic/Section
IP Classless Addressing Block Sizes and "Classful" Network Equivalents
Previous Page
Pages in Current Topic/Section
12
3
4
Next Page
IP Datagram Encapsulation and Formatting
Next Topic/Section

IP CIDR Addressing Example
(Page 3 of 4)

Second Level of Division

Let's say we set aside subnetwork #0 above for future ISP allocations. We then choose to divide the second subnetwork, into four. These we will then further subdivide into different sizes to meet our customer needs. To divide into four groups we need two more bits from the host ID of subnetwork #1, shown highlighted and underlined next to the original subnet bit:

01000111 01011111 00000000 00000000

These two bits are replaced by the patterns 00, 01, 10 and 11 to get four sub-subnetworks. They will be “/18” networks of course, since we took two extra bits from the host ID of a “/16”:

Sub-subnetwork #1-0: 01000111 01011111 00000000 00000000 (71.95.0.0/18)
Sub-subnetwork #1-1: 01000111 01011111 01000000 00000000 (71.95.64.0/18)
Sub-subnetwork #1-2: 01000111 01011111 10000000 00000000 (71.95.128.0/18)
Sub-subnetwork #1-3: 01000111 01011111 11000000 00000000 (71.95.192.0/18)

Each of these has 16,382 addresses.


Previous Topic/Section
IP Classless Addressing Block Sizes and "Classful" Network Equivalents
Previous Page
Pages in Current Topic/Section
12
3
4
Next Page
IP Datagram Encapsulation and Formatting
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.