IPV6 Tutorial 4 IPv6 address syntax

https://4sysops.com/archives/ipv6-tutorial-part-4-ipv6-address-syntax/

Now so you know about the new features of IPV6, it's time to has a closer look at the practical details.

In this post, I'll give a short summary about the IPV6 address syntax.

It is essentially a condensed version of the corresponding part in Microsoft's white paper "Introduction to IP version 6."

Colon Colon

Colon-hexadecimal representation

An IPV6 address consists of-bits and is presented in eight 16-bit blocks. Each 16-bit block was converted to a four-digit hexadecimal number. Blocks is separated by colons.

EXAMPLE:2001:0DB8:0000: 2F3B:02AA:00FF:FE28:9C5A

Total is 32 bytes, divided into 8 groups, 2 bytes per group; 2 bytes in hexadecimal, 0x2001 the first byte is 0x20 the second byte is 0x01

Leading Zero suppression

Because IPV6 addresses is quite long, the leading zeroes within a 16-bit block can be removed, but each block must has a t least a single digit.

EXAMPLE:2001:DB8:0: 2f3b:2aa:ff:fe28:9c5a

Zero compression

A contiguous sequence of 16-bit blocks set to 0 can is replaced with the so-called double colon (::). Zero compression can only is applied once in an IP address.

To determine how many blocks has been omitted, you just has to count the remaining blocks and subtract this number from 8.

EXAMPLE:FE80:0:0:0:2AA:FF:FE9A:4CA2 can is zero compressed to FE80::2AA:FF:FE9A:4CA2.

There are only 5 sets of data, with a double colon in the middle indicating a compressed 0,8-5=3; 3 groups of 0000 are compressed.

IPV6 Prefix

IPV6 prefixes is used to express IPV6 subnets, routes, and address ranges.

The syntax of IPV6 prefixes looks like this: address/prefix-length.

It is comparable to the Classless Inter-Domain Routing (CIDR) notation for IPv4 (for instance, 192.168.0.0/16 represents a Class B subnet): subnet masks (subnet mask) is no longer used in IPv6.

Example: 21da:d3:0:2f3b::/ represents a subnet of addresses, where the first TS is fixed and the last bits is variable.

Admittedly, IPV6 addresses look somewhat complicated compared to the relatively simple IPv4 addresses.

Rest assured that typos in IPV6 addresses would knock down quite a few systems once IPV6 starts replacing IPV4.

But that's the price of the large address space. I guess, we'll get used to it.

In my next post, I'll discuss the different types of IPv6 addresses.

I promise that things won ' t get easier.

In the next post of this tutorial I'll say some general words about the IPV6 address types and I'll introduce the most Address type, the global IPv6 unicast address.

IPV6 Tutorial 4 IPv6 address syntax