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Ipv6: An acronym to shake the networked world
There is a shortage of house numbers in the global village. That's right, the young net is already outgrowing its clothes. Here, Achim Killer looks at this and other reasons why IP version 6 beckons...

By editorial@silicon.com

Published: Monday 19 March 2001

There seem to be many good reasons for introducing the next generation of IP (internet protocol). However, one of them is urgent - the global network is simply running out of addresses, with the mobile boom heavily contributing to the problem.

It is possible to code four billion internet addresses using 32 bits, and the current protocol version - version 4 - allows for this. When it was introduced in 1973 four billion was an unimaginably large number. Less than 1,000 computers were connected to the network then. Now, only 40 per cent of 32 bit addresses remain free.

ALE (Address Lifetime Expectation), a working party set up by the Internet Engineering Task Force (IETF) in 1990, forecasts that in 2005 the address space will have been used up. Some think the end will come sooner.

Crucially, in the header for the new protocol version there are 128 bits for senders and recipients. That equates to several quadrillion IP addresses for every individual alive.

But IPv6 has even more advantages. It supports Quality of Service (QoS) and thus increasingly important real time communication for multimedia. What's more, the header is more compact in spite of longer addresses. Therefore routers can process packets faster. Also the IPSec security protocol is provided as standard. It ensures hackers cannot look at or change data packets. It also authenticates the sender.

But the experts agree that all these things alone don't justify converting from IP version 4 to 6. Axel Clauberg, a consulting engineer at Cisco, said it's just "nice to have."

Hubert Martens, MD at Munich's Multinet Services, said: "To a limited extent I can get all these advantages without IPv6."

"QoS also goes with ToS," added Martens. ToS (Type of Service) is a field in the IPv4 header. The priority allocated to a data package on the net can be coded here too. It is only in very exotic cases that this isn't enough. For example, if packets are dealt with in various sub networks with different priorities and so the prioritising must be carried along routes that have already been covered.

Treating data packets as preferential is only one method of enabling real time communication. Martens believes the significance of this is overrated. He said: "A little more bandwidth is, on the whole, better."

Many experts consider that even the advances IPv6 brings to security are overvalued. However, it cannot be disputed that the need for security is increasing. Attacks by hackers with false IP addresses - spoofing - hold up ecommerce. As users are increasingly surfing on the move, even more data must be transferred without wires. The so-called 'air interface' is, however, more easily compromised than a fixed wired network.

But the IPSec protocol can also be run with IPv4, although it only works with an extended security infrastructure. IPSec works with authenticated keys that must be publicly accessible. "But there is no sensible public key infrastructure for IPSec," criticised Cisco's Clauberg. PKI regulates certification and exchange of public keys.

Converting to the next IP version also brings with it risks. Applications based on the Stacks protocol must often be rewritten. Only then can they deal with the longer address fields. Some think the year 2000 problem was nothing compared to the switch to IPv6.

In spite of this, change is inevitable. The reasons are the new mobile technologies: GPRS (General Packet Radio Service) and subsequently UMTS (Universal Mobile Telecommunications System). They are used for data communication and are - unlike surfing with GSM mobile phones - so-called 'always-on' technologies. Terminals are always online - and so each need a fixed IP address. It will no longer be enough for a service provider to allocate them dynamically as is currently the case.

IPv6 will be spread first of all at the edges of the internet, but IPv4 is likely to dominate the backbone for a long time. That means IPv6 packets for transport over IPv4 routes must be packed separately. This can be done using MPLS (Multiprotocol Label Switching) or tunnelling. In the latter case an old four-digit code comes before the new version 6 header. But it does not code the final target address, only the entrance point into the IPv6 based sub network.

The gradual change to the internet from the outside in will depend on the availability of IPv6 compatible products. Old important operating system manufacturers will also support the new protocol in the meantime. IBM's Unix, AIX, has had this feature for years. And for Windows 2000 there is already the beta version of an IPv6 stack. But routers still need time. The first Cisco machines with the new address scheme will be available in the next three months.

In all probability the new mobile standards will only trigger a first IPv6 wave. New address hungry networks are already in existence. Cisco internal market forecasts expect a boom in home networking after 2002. Washing machines with internet addresses are already on sale

Indeed, visionaries think about universally communicating household articles. Vint Cerf, often called the father of the internet, takes every opportunity talk about them. With this in mind, and mobile phone usage proliferating, a networked future seems assured. There seems little doubt a greater number of IP addresses must follow.

By Achim Killer