Introduction to IPv6

By -

Let’s start with simple explanation of the new format. As you may know, the new-generation-IP talk started in the early 1990s when we were slowly running out of IP addresses. We had quite a few proposals for the new address format but in 1995 IPv6 was selected and the RFCs were officially entered into the RFC repository.
IPv6 was created based off of IPv4 with some of the useful IPv4 features carried over to IPv6. There were many changes to the new IP format, however, and I will list some of them here below.
  • Expanded Addressing Capabilities: IPv6 address size increased from 32 bits to 128 bits. Because of the increased size the new address will support a higher number of nodes, more levels of addressing hierarchy, and a much simpler autoconfiguration of addresses for remote users. A new address type was created, called anycast.
  • Header Format Simplification: To simplify the entire IP format, some of the IPv4 header fields were dropped or made optional in IPv6.
  • Flow Labeling Capability: There is a new quality-of-service (QOS) capability that enables the labeling of packets belonging to particular traffic “flows” with special handling, such as real-time service.
  • Authentication and Privacy Capabilities: There are new built-in extensions to support security options
Here is an example of an old and new addressing scheme:
     Old – IPv4 address:     129.14.12.200
     New – IPv6 address:     1029:9183:81E2:0000:0000:01D5:2115:019B
As you can see the new generation IP address is quite different from what we are used to. The IPv6 address is in a hexadecimal format. The only good thing in the IPv6 address format is that we can use compressions. There are rules, however, on how and when to use them.

Zero Compression

If you have consecutive fields of zeroes in the IPv6 address, you can express them with two colons.
It does not matter if you have two, three, four or eight fields of zeros, you can simply type two colons next to each other and that will represent all the consecutive zeros fields. These fields of zeros must follow each other.
A very important key to this rule is that you can only use that compression once in an IPv6 address. For example:
     Original IPv6 format:          1234:1234:0000:0000:1234:0000:0000:1234
     Using zero compression:     1234:1234::1234:0000:0000:1234
Notice how I used zero compression only ONCE in this example. Writing this address like this:
1234:1234::1234::1234
would make this address incorrect and every router would give you an error.

Leading Zero Compression

In a leading zero compression you can drop leading zeros in an address, in any field, as long as there is at least one number left. What that means is that if the address field is all zeros, you must leave at least one zero in that field. Here is an example:
     Original IPv6 format:                       1234:0000:1234:0000:1234:0000:0123:1234
     Using leading zero compression:     1234:0:1234:0:1234:0:123:1234
You can also combine these compressions and use them together in an address:
     Original IPv6 format:          1234:0000:0000:1234:0002:0033:0012:0123
     With both compressions:     1234::1234:2:33:12:123
     (zero and leading compression)
Zero Compression uses the double-colon to replace the second and third block of numbers, which were all zeroes. Leading zero compression replaces the “0s” at the beginning of each of the last four blocks. Just be careful and take time when using both zero compression and leading zero compression. They key is to remember that you can use zero compression only once in a single IPv6 address.

IPv6 to IPv4 conversion

  1. Lets start with an IPv6 address that can be converted to IPv4:IPv6 address:     ::D190:4E71 – the double colon is zero compression
  2. Since the IPv6 is in a hexadecimal format we will start with the first number, which is D1 and convert that into decimal. In hexadecimal D=13 and 1=1, so we have:D1 – 13 units of 16 and 1 unit of 1 = 209
  3. The second number is: 90. Therefore we have:90 – 9 units of 16 and 0 units of 1 = 144
  4. Next number is: 4E.4E – 4 units of 16 and 14 units of 1 = 78
  5. And the last number: 71.71 – 7 units of 16 and 1 unit of 1 = 113
  6. IPv4 address after conversion is: 209.144.78.113

Comments

Post a Comment

Popular posts from this blog

Android Essentials: Using the Contact Picker

By -
Image
This tutorial will not only show you how to launch the contact picker and get results, but also how to use those results in Android SDK 2.0 and above. Getting Started This tutorial will start out simple, but then we’ll get in to some of the technical details of using Contacts with the ContactsContract class, which was introduced in API Level 5. Make sure you have your Android development environment installed and configured correctly. You’re free to build upon any application you have, start a new one from scratch, or follow along using the InviteActivity code in our open source project . We’ll then be adding functionality to allow a user to choose one of their existing contacts and send a canned message to them. We’re going to dive right in, so have all of your code and tools ready. Finally, make sure your device or emulator has some contacts configured (with names and emails) within the Contacts application. Step 1: Creating Your Layout There are two essential form control
Read more

Using CreateJS - EaselJS

By -
Image
In this tutorial we will be exploring the CreateJS suite of libraries. CreateJS is suite of JavaScript libraries and tools for building rich, interactive experiences with HTML5. The CreateJS suite is divided into four libraries. EaselJS - Makes working with HTML5 canvas easy. TweenJS - For tweening HTML5 and JavaScript properties SoundJS - Lets you easily work with HTML5 audio PreloadJS - Lets you manage and coordinate loading of assets The first library we will look at is EaselJs. Lets get started! EaselJS Explained EaselJS is a library for working with the HTML5 canvas. It consists of a full, hierarchical display list, a core interaction model, and helper classes to make working with Canvas much easier. Getting up and running with EaselJS could not be easier. You'll need to define a canvas element in your HTML and reference it in your JavaScript. EaselJS uses the notion of a Stage which is the top level Container for the display list ( the stage will be your c
Read more

How to Create a Yoga Goddess Illustration in Adobe Illustrator

By -
Image
As the music begins to play, a soft breeze fills the space with the undeniable smell of magnolia blossoms. She gracefully enters and begins a “tree pose” with her hands in Namaste form. Our female figure is inspired by the Indian culture for its gorgeous use of color and the grace of its yoga formations. I hope you’ll enjoy the journey as we retrace, step by step to enlightenment.  1. Becoming Flesh and Blood Step 1 Our first step will be to bring in our sketch. I've scanned her in at 300 dpi to catch as much of the detail as possible. I'm not as picky about my choice of initial drawing tools, and this particular project was completed with a mechanical pencil. We'll be working with a clean line quality from Adobe Photoshop and now we can begin to work. I'm working in Adobe Illustrator at a size of 8.5 x 11 inches for this specific project. When I'm ready to start my layers, I'll label my first layer as "Sketch" and lock the layer to make su
Read more