Title: Analyze IPv6 Addressing
Course: CIS 208: Linux/UNIX III: Intermediate System Administration, Networking, and Security ~ For IGNITE Review > Section: Learning Modules

Analyze IPv6 Addressing

The conversion to IPv6 has been coming for years; however, it has been a slow process.  Hardware has to be able to use IPv6.  Support personnel also need to be able to work with it.  IPv6 is very different from IPv4 in several ways.  The biggest difference you will see is it has eight quartets instead of four octets.  It is also represented in hexadecimal rather than binary, and it doesn't use a subnet mask.  The Key Facts listed below list more of the most common differences.

Parts of an IPv6 Addresses

An IPv6 address is divided into two parts, the Prefix and the Interface ID. The Prefix is the first 64 bits of the address and is referred to as a global routing prefix since it knows the geography of the address. The Interface ID is made up of the last 64 bits and is assigned to the interface rather than the host. This is like the host portion of an IPv4 address that must be unique. Because of automatic host identification an interface can get an address assigned automatically even if there is no DHCP server enabled.

Key Facts

Prefix

- First 64-bits
- Referred to as a global routing prefix
- Can be divided into parts – region, ISP, network, subnet

Interface ID

- Second 64-bits
- Assigned to interface – not host
- Unique within a subnet
- Can use automatic host ID to get address

Source: Lesson_6_Network_Fundamentals

"IPv6" by Wikipedia Community retrieved from http://en.wikipedia.org/wiki/IPv6 is used under a Creative Commons Attribution http://creativecommons.org/licenses/by-sa/3.0/.

IPv6 address classes

IPv6 addresses are classified by the primary addressing and routing methodologies common in networking: unicast addressing, anycast addressing, and multicast addressing.^[1]

- A unicast address identifies a single network interface. The Internet Protocol delivers packets sent to a unicast address to that specific interface.
- An anycast address is assigned to a group of interfaces, usually belonging to different nodes. A packet sent to an anycast address is delivered to just one of the member interfaces, typically the nearest host, according to the routing protocol’s definition of distance. Anycast addresses cannot be identified easily, they have the same format as unicast addresses, and differ only by their presence in the network at multiple points. Almost any unicast address can be employed as an anycast address.
- A multicast address is also used by multiple hosts, which acquire the multicast address destination by participating in the multicast distribution protocol among the network routers. A packet that is sent to a multicast address is delivered to all interfaces that have joined the corresponding multicast group.

IPv6 does not implement broadcast addressing. Broadcast's traditional role is subsumed by multicast addressing to the all-nodes link-local multicast group ff02::1. However, the use of the all-nodes group is not recommended, and most IPv6 protocols use a dedicated link-local multicast group to avoid disturbing every interface in the network.