Script: IPv6 audio primer

Network World Fusion

IPv6 is the Internet Engineering Task Force's next-generation Internet communications protocol. IPv6 has a bunch of shiny new features that proponents say will take Internet technology well into the future. In this primer, we'll tell you what these new features are and how they could benefit corporations and Internet users over the coming years.

The current version of the Internet's communications protocol, IP Version 4 is a bit like an old, reliable car. It needs some serious bodywork, but the engine just won't quit.

Still, despite its reliability, few in the industry doubt IPv4's mortality. It has address limitations, performance problems and a raft of other deficiencies. All need to be addressed for the Internet and related IP technologies to move forward - especially in light of the Internet's exploding popularity and growing use as a multimedia delivery system.

As the use of Internet and IP-related technologies increases, the strains placed on IPv4 become more evident. Big companies are having trouble getting addresses for new users. New applications with multimedia capabilities are being delayed or not deployed at all because there is no way to prioritize traffic flow. Administrators find it difficult to add, delete and change accounts on large IP-based networks.

Enter IPv6. Probably the biggest and most talked about new component IPv6 brings to the table is a larger address space. Addresses define a specific node on the network where data, such as mail or file transfers should be sent. Most people are familiar with Internet addresses, such as xyz@nww.com.

Addressing has been the bane of the Internet's existence for years. Most experts expect the current stockpile of 4.3 billion IPv4-based addresses to be eaten up in the next few years - in large part because of the inefficient way addresses are currently doled out.

IPv6 has a 128-bit address space versus IPv4's 32-bit space, which will allow for a geometric increase in the number of possible addresses. This means a far greater number of users will be able to tie directly into the 'Net. It should also increase the scalability of IP-based networks in the corporate environment.

IPv6 will also divvy up addresses differently. The idea is to reserve groups of addresses for specific types of use and leave lots of unallocated address space for future growth. For example, IPv4 devices will keep their existing eight-digit designations, but ISPs will get a three-digit code that will remain unique to those vendors. Other designations will be reserved for local use or deployment by devices that support advanced functions such as multicast operations.

IPv6 will also enable host machines to automatically discover the information, such as the address of a local router, needed to connect to the Internet or corporate IP backbone. Analysts at Forrester Research say that this feature alone will eliminate so much manual configuration minutia from users' lives it will pay back the cost of converting to IPv6-based technology within a year.

This autoconfiguration feature will give users with thousands of IP-based devices an easy way to make new additions, changes and deletions from current environments with ease. It gives TCP/IP a plug-and-play quality only dreamed of in the past.

Addressing isn't the only issue being addressed in IPv6. In order to speed up IPv6 transmissions, the protocol's header has been greatly simplified with unused fields being made optional. Headers are the part of a transmission that guide data to its proper destination. With this improved header, data should traverse IP-based nets much more quickly and with less overhead.

Other new components of IPv6 include technology that would prioritize the flow of IP-based traffic over an TCP/IP backbone. Called "flow labeling," the feature would provide a standard way for workstations or hosts to specify special handling of certain traffic types. The feature is important for future multimedia or other applications that generate lots of interactive traffic. For example, an important videoconference could be labeled to ensure it receives transmission priority over, say, routing remote file transfers.

IPv6's IETF designers still have to address security issues. Currently, the IPv6 specification states that implementations must, at the very least, have packet-level encryption and a secure encryption algorithm. For many, this means using IPSEC (IP Security) technology. Early in the IPv6 development process, export rules were tight, limiting the level of packet-level encryption available. Today, export rules are more relaxed, though some hurdles still exist.

Since there is a massive installed base of IPv4-based hardware and software, the transition to IPv6 will only be possible if it is made as easy as possible. What the IETF has come up with is a tunneling technique that allows for the gradual conversion of IPv4 to IPv6. For example, when IPv6-based hosts need to communicate over an IPv4-based router net, the IPv6 data will be encapsulated in an IPv4 package. The Simple Internet Transition Method, or RFC 1933, describes this and other requirements for moving routers and hosts seamlessly to the IPv6 world.

While the benefits of moving to IPv6 are readily apparent, the march towards its implementation has been slow. The reasons for this inactivity are many. For example, vendors have tweaked the addressing scheme in IPv4 to give it a much longer life than many predicted. New technologies have also extended the life of IPv4. One example is the Dynamic Host Configuration Protocol, which enables automatic registration of IP host resources and hands out new TCP/IP addresses as new devices come online.

Still, a number of vendors are working on products implementing the new protocol. Sun, IBM, Digital and Microsoft already offer IPv6-based products, while Cisco has pledged to do so. NTT is offering commercial-grade IPv6 service, while NASA and a number of universities across the country have experience running IPv6 test beds.

If you can deal with IPv4's kinks, such as its inability to prioritize traffic or make net changes easily, there may be no immediate need to change. But if your routers are already bulging at the seems with overloaded memory caches and you want to deploy new applications that would benefit from multicasting or other advanced features IPv4 does not support, you'll probably want to start bugging your vendors for IPv6 products.

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