IPv6 deployment

IPv6 deployment and upgrade strategies - introduction
This article is intended as a guide to assist new entrants into the IPv6 world. We will show three successively more complex examples of migration strategies from IPv4 to IPv6. The examples utilize Linux-based routers, firewalls, and proxy servers, although the attached workstations are assumed to be Windows-based machines. These examples will help the user understand the deployment of (or migration to) an IPv6 network.

Internet Protocol Version 6 (IPv6), also referred to as Internet Protocol Next Generation (IPng), is the latest major network layer protocol. It is an extension to Internet Protocol Version 4 (IPv4), which is the current Internet standard. IPv6 was originally developed to handle a number of issues that were either considered weaknesses or limitations of IPv4. Most notably and obviously, IPv6 has an address space of 128 bits (versus 32 bits in IPv4), which allows a much larger number of machines to be connected to any network. In addition, IPv6 improves router performance through the use of more succinct network datagram headers, multicast membership maintenance, reduced network broadcasts, and delegation of packet fragmentation. These techniques provide more efficient network architecture from which to deploy next generation Internet technologies.

Although IPv6 contains a number of improvements over IPv4, there are also a number of challenges that face implementers and administrators wishing to deploy this advanced architecture. First of all, the fact that the technology is new and not widely used represents a major challenge to implementers. However, many of the challenges are superficial because the underlying system design has not changed radically. Thus many of the changes from IPv4 to IPv6 are superficial. For instance, IPv6 no longer uses "private addresses" [RFC1918] but instead uses two types of network addresses called "site-local" and "link-local" addresses. The Address Resolution Protocol and the Router Discovery Protocol have been replaced with the Neighbor Discovery Protocol. DHCP (Dynamic Host Configuration Protocol) is no longer necessary in IPv6 since hosts can negotiate their addresses on startup. The only major change is that Network Address Translation (employed in routers and firewalls when acting as a surrogate source in network communications) is no longer implemented in IPv6 (nor is it necessary since there are enough IP addresses for every device).

The remainder of this article can be found in the remaining sections:

IPv6 and IPv4 headers compared
Headers

IPv6 and IPv4 addressing compared
Addressing

IPv6 and IPv4 maintenance protocols compared
Maintenance protocols

Implementing a simple SOHO network using IPv6
SOHO network

Implementing a small development network using IPv6
Small development network

Implementing a medium-sized IPv6 campus network
Campus network

Conclusions
Conclusion