So, what do you know about IPv6 Addressing?
The 32-bit binary IPv4 Address format allows for nearly 4.3 Billion addresses. Because of the design of the address space, some addresses cannot be assigned, leaving the total assignable addresses around 3.7 Billion. Of the addresses that cannot be assigned, some are reserved for Multicasting, Broadcasting, Loopback testing, Private Addressing and Research, and of course each time you divide a network address up into subnets you need a subnet ID and Broadcast address.
An IPv6 address is a 128-bit binary address which is normally written in hexadecimal and provides 3.4 x 1038 IP Addresses. It will certainly not be as easy to remember some IPv6 addresses like we can IPv4 addresses, but like everything we will get used to it. There should be enough of these addresses to provide for future growth of the Internet for many years to come and allow for the easy growth and expansion of the Internet.
IPv6 Unicast addresses work in much the same way as IPv4 Unicast addresses, in that they are designed to be configured on a single interface and represent a single interface or host. However, in contrast to the way the IPvv4 address space was broken down into Classes A-E, the unicast address space has been broken down into a number of functional categories.
Global Addresses for communication on the Internet
Link Local Addresses to be used for Neighbour discovery, Router discovery and Automatic Address Assignment. These addresses are not routable on the Internet.
Site Local Addresses, which are the equivalent of IP version 4 RFC 1918 local addresses and are not routable on the Public networks.
Multicast Addresses, where group communications are needed such as Voice and Video conferencing. This constitutes a fairly large chunk of address space as multicasting technologies are seen to proliferate.
Anycast Addresses, which are a new concept and not available with IPv4. Designed to be used in situations where a distributed group of servers are to provide an identical service. Routers will route packets to the nearest server in an Anycast group. We often refer to Anycast Addresses as being One to the Nearest!!
Loopback Addresses. In the IPv4 address space a whole Class A network was allocated for loopback testing, which is over 16 million addresses, when in reality we regularly only use one which is 127.0.0.1. IPv6 has a single loopback address of 0:0:0:0:0:0:0:1.
Our next post will go into more detail, particularly with the Global, Link Local and Site Local addresses.
IPv6 is covered in some of our instructor-led training courses.