About IPv6 | IPv6 Forum Pacific Islands

About IPv6

Internet Protocol version 6 (IPv6) is a network layer IP standard used by electronic devices to exchange data across a packet-switched internetwork. It follows IPv4 as the second version of the Internet Protocol to be formally adopted for general use.

IPv6 is intended to provide more addresses for networked devices, allowing, for example, each cell phone and mobile electronic device to have its own address. IPv4 supports 4.3×109 (4.3 billion) addresses, which is inadequate for giving even one address to every living person, much less support the burgeoning market for connective devices. IPv6 supports 3.4×1038 addresses, or 5×1028(50 octillion) for each of the roughly 6.5 billion people alive today.

Invented by Steve Deering and Craig Mudge at Xerox PARC, IPv6 was adopted by the Internet Engineering Task Force in 1994, when it was called “IP Next Generation” (IPng). (Incidentally, IPv5 was not a successor to IPv4, but an experimental flow-oriented streaming protocol intended to support video and audio.)

As of August 2006, IPv6 accounts for a tiny percentage of the live addresses in the publicly-accessible Internet, which is still dominated by IPv4. The adoption of IPv6 has been slowed by the introduction of network address translation (NAT), which partially alleviates address exhaustion. The Federal government of the United States has specified that the network backbones of all federal agencies must deploy IPv6 by 2008.[1]

It is expected that IPv4 will be supported alongside IPv6 for the foreseeable future with hosts running dual-stack software.

IPv6 offers numerous advantages over IPv4. Some of these are:

Larger address space

The main feature of IPv6 is the larger address space: addresses in IPv6 are 128 bits long.

The larger address space avoids the potential exhaustion of the IPv4 address space without the need for NAT and other devices that break the end-to-end nature of Internet traffic.

128 bits might seem overkill to achieve that goal. However, since IPv6 addresses are plentiful, it is reasonable to allocate addresses in large blocks, which makes administration easier and avoids fragmentation of the address space, which in turn leads to smaller routing tables. The current allocation policies allocate 64 bits of address space to an end-user, and 96 bits or more to an organization.

A technical reason for selecting 128-bit for the address length is that since most future network products will be based on 64 bit processors, it is more efficient to manipulate 128-bit addresses. The drawback of the large address size is that IPv6 is less efficient in bandwidth usage, and this may hurt regions where bandwidth is limited.

Another advantage of the larger address space is that it makes scanning certain IP blocks for vulnerabilities significantly more difficult than in IPv4, which makes IPv6 more resistant to malicious traffic.

Stateless autoconfiguration of hosts

IPv6 hosts can be configured automatically when connected to a routed IPv6 network. When first connected to a network, a host sends a link-local multicast request for its configuration parameters; if configured suitably, routers respond to such a request with a router advertisement packet that contains network-layer configuration parameters.

If IPv6 autoconfiguration is not suitable, a host can use stateful autoconfiguration (DHCPv6) or be configured manually.

Stateless autoconfiguration is only suitable for hosts; routers must be configured manually or by other means.

Multicast

Multicast (both on the local link and across routers) is part of the base protocol suite in IPv6. This is different to IPv4, where multicast is optional.

IPv6 multicast is, however, not yet widely deployed across routers.

IPv6 does not have a link-local broadcast facility; the same effect can be achieved by multicasting to the all-hosts group with a hop count of one.

Jumbograms

In IPv4, packets are limited to 64KiB of payload. When used between capable communication partners, IPv6 has support for packets over this limit, referred to as jumbograms. Use of jumbograms might improve performance over high-throughput networks.

Faster routing

By using a simpler and more systematic header structure, IPv6 was supposed to improve the performance of routing. Recent advances in router technology, however, may have made this improvement obsolete.

Network-layer security

IPsec, the protocol for IP network-layer encryption and authentication, is an integral part of the base protocol suite in IPv6. It is, however, not yet deployed widely except for securing BGP traffic between IPv6 routers.

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