Ipv6 Migration

In 1983 when IPv4 was first deployed, its capability of a little over 4 billion unique numbers seemed sufficient. As of 2001, 3 billion have been assigned. With the new types of services that we will have in the future, we will not only need IP addresses for personal computers and servers, but for mobile services based on GPRS (General Packet Radio System), the UMTS (Universal Mobile Telephone Service), high-speed access and "always on" mode, on-line electronics and communicating vehicles, home automation applications and sensor networks. A diminishing supply of IP numbers required a solution. Internet Protocol version 6 (IPv6) is the new version of its predecessor Internet Protocol version 4 (IPv4). Introduced by the IETF (Internet Engineering Task Force) on July 25, 1994 in RFC 1752 (Request for Comments), but draft standard didn't come out until August 10, 1998 (http://playground.sun.com/pub/ipng/html/ipng-DS.txt).

Does everyone have to migrate?

Japan has mandated the migration to Ipv6 by 2005, while the European Union has set up an Ipv6 task force to promote the issue (http://www.wirelessweek.com/index.asp?layout=article&articleid=CA90251). The 3GPP effort has mandated IPv6 for the next generation of wireless networks. In its Release 2000 specification, the requirement for IPv6 to be built into the wireless IP multimedia subsystem started in 2002. This means that IP routers and servers for voice and data must support IPv6 and be able to assign IPv6 addresses to handheld devices (http://www.icr.a-star.edu.sg/ipv6/).

Most businesses have already been utilizing a work-around process called NAT (Network Address Translation RFC 1631). This is a method where an entire network can be mapped to a single IP address.

Ipv6 Mechanics

IPv6 is defined in a number of RFC documents primarily RFC 2460. IPv6 is also referred to as IP Next Generation (IPng). There are five categories of changes, as detailed in RFC 2460, between IPv4 and IPv6. We will examine these changes as benefits or improved offerings of the next generation of the protocol. Those changes are as follows:

 Expanded Addressing Capabilities

 Header Format Simplification

 Improved Support for Extensions and Options

 Flow Labeling Capability

 Authentication and Privacy Capabilities

http://www.ietf.org/rfc/rfc2460.txt?number=2460

Expanded addressing capabilities allow IPv6 to increase the IP (Internet Protocol) address size from 32 bits to 128 bits to support more levels of addressing hierarchy, a much greater number of addressable nodes, and simpler auto-configuration of addresses. The scalability of multicast routing is improved by adding a "scope" field to multicast addresses. A new type of address called an "anycast address" is defined. The anycast address is used to send a packet to any one of a group of nodes. http://www.ietf.org/rfc/rfc2460.txt?number=2460

Header format simplification enhances the header field by dropping some IPv4 header fields or making those fields optional. The purpose this is to reduce the processing cost of packet handling and to limit the bandwidth cost of the IPv6 header. http://www.ietf.org/rfc/rfc2460.txt?number=2460

Improved support for extensions and options introduces the changes in the way IP header options are encoded. This allows for more efficient forwarding, less stringent limits on the length of options, and greater flexibility for introducing new options in the future. http://www.ietf.org/rfc/rfc2460.txt?number=2460

Flow labeling capability is added to enable the labeling of packets belonging to traffic "flows" for which a sender requests special handling, such as non-default quality of service or "real-time" service. http://www.ietf.org/rfc/rfc2460.txt?number=2460

Authentication and privacy capabilities include extensions to support authentication, data integrity, and (optional) data confidentiality.

Figure 1: IPv6 Header Format

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

|Version |Traffic Class | Flow Label |

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

|Payload Length |Next Header | Hop Length |

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

+ +

| |

+ Source Address + +

| |

+ +

|++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++|+ +

| |

+ Destination Address

| |

+ +

| |

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

http://www.ietf.org/rfc/rfc2460.txt

Header Field Definitions

 Version: 4 bit Internet Protocol version number = 6

 Traffic Class: 8 bit traffic class field

 Flow Label: 20 bit flow label.

 Payload length: 16 bit unsigned integer. Length of the IPv6 payload, i.e., the rest of the packet following this IPv6 header, in octets. Any extension headers present are considered part of the payload and are included in the length count.

 Next Header: 8-bit selector, which identifies the