The need for migrating enterprise networks from IPv4 to IPv6 is driven by a number of different technological, business, and social factors. The most important of these are:
- The exponential growth of the Internet is rapidly exhausting the existing IPv4 public address space. A temporary solution to this problem has been found in Network Address Translation (NAT), a technology that maps multiple private (intranet) addresses to a (usually) single, public (Internet) address. Unfortunately, using NAT-enabled routers can introduce additional problems, such as breaking end-to-end connectivity and security for some network applications. In addition, the rapid proliferation of mobile IP devices is accelerating the depletion of the IPv4 public address space.
- The growing use of real-time communications (RTC) on the Internet, such as Voice over IP (VoIP) telephony, instant messaging (IM), and audio/video conferencing, exposes the limited support for Quality of Service (QoS) currently provided in IPv4. These new RTC technologies need improved QoS on IP networks to ensure reliable end-to-end communications. The design of IPv4 limits possible improvements.
- The growing threats faced by hosts on IPv4 networks connected to the Internet can be mitigated considerably by deploying Internet Protocol security (IPsec), both on private intranets and on tunneled connections across the public Internet. However, IPsec was designed as an afterthought to IPv4 and is complex and difficult to implement in many scenarios.
IPv6, developed by the Internet Engineering Task Force (IETF) to solve these problems, includes the following improvements and additions:
- IPv6 increases the theoretical address space of the Internet from 4.3 x 109 addresses (based on 32-bit IPv4 addresses) to 3.4 x 1038 possible addresses (based on 128-bit IPv6 addresses), which most experts agree should be more than sufficient for the foreseeable future.
- The IPv6 address space is designed to be hierarchical rather than flat in structure, which means that routing tables for IPv6 routers can be smaller and more efficient than for IPv4 routers.
- IPv6 has enhanced support for QoS that includes a Traffic Class field in the header to specify how traffic should be handled and a new Flow Label field in the header that enables routers to identify packets that belong to a traffic flow and handle them appropriately.
- IPv6 now requires IPsec support for standards-based, end-to-end security across the Internet. The new QoS enhancements work even when IPv6 traffic is encrypted using IPsec.
Understanding how IPv6 works is essential if you plan to benefit from IPv6 by deploying it in your enterprise. The following sections provide an overview of key IPv6 concepts, features, and terminology.
Note For more detailed information on IP concepts, features, and terminology, see the white paper titled "Introduction to IP Version 6" at http://www.microsoft.com/downloads/details.aspx?FamilyID=CBC0B8A3-B6A4-4952-BB E6-D976624C257C&displaylang=en.
In this tutorial:
- Deploying IPv6
- Understanding IPv6
- Understanding IPv6 Terminology
- Understanding IPv6 Addressing
- Understanding IPv6 Prefixes
- Understanding IPv6 Address Types
- Understanding Unicast Addresses
- Identifying IPv6 Address Types
- Understanding Interface Identifiers
- Comparing IPv6 with IPv4
- Understanding IPv6 Routing
- How IPv6 Routing Works
- IPv6 Route Determination Process
- IPv6 Routing Table Structure
- Understanding ICMPv6 Messages
- Understanding Neighbor Discovery
- Understanding Address Autoconfiguration
- Understanding Name Resolution
- Understanding Name Queries
- Understanding Name Registration
- PTR Records and IPv6
- IPv6 Enhancements in Windows 7
- Summary of IPv6 Enhancements in Windows 7
- Configuring and Troubleshooting IPv6 in Windows 7
- Configuring IPv6 in Windows 7 Using the User Interface
- Configuring IPv6 in Windows 7 Using Netsh
- Other IPv6 Configuration Tasks
- Enabling or Disabling IPv6
- Disabling Random Interface IDs
- Resetting IPv6 Configuration
- Displaying Teredo Client Status
- Troubleshooting IPv6 Connectivity
- Planning for IPv6 Migration
- Blocking Teredo
- Understanding ISATAP
- Migrating an Intranet to IPv6
- Step 1: Upgrading Your Applications and Services
- Step 2: Preparing Your DNS Infrastructure
- Step 3: Upgrading Your Hosts
- Step 4: Migrating from IPv4-only to ISATAP
- Step 5: Upgrading Your Routing Infrastructure
- Step 6: Upgrading Your DHCP Infrastructure
- Step 7: Migrating from ISATAP to Native IPv6
- The Advantages of IPv6
- Address Resolution in IPv6