When the father of the Internet, Vint Cerf, says businesses need to start planning for IPv6 migration now, the time has come to take action. Users of the Internet Protocol (IP) could face serious problems in a few years with the exhaustion of IPv4 addresses.1
The theoretical limit of IPv4’s 32-bit space addressing system is 4.3 billion devices. Considering the global population is now approximately 6.6 billion people, with IPv4 we could not even afford to give a single IP address to every person on Earth. The problem has been further exacerbated by inefficiencies in the allocation of addresses and the ‘unfair’ distribution of addresses, for instance American universities hold more Class B addresses (the optimal class for large corporates) than the whole of China.
With conservative projected demand for three to four billion Internet addresses over the next five years, there is potentially an address shortage on the horizon. Opinions vary as to the exact year when the World will run out of IPv4 address space but clearly action will need to be taken.
An IPv4 based solution?
Solutions based on IPv4 inevitably result in compromises to the original concept of IP functionality. A very popular approach is not to assign a worldwide unique address to every user’s machine, but to assign them private addresses, and ‘hide’ several machines behind one official, globally unique address. This approach is called Network Address Translation (NAT) or ‘IP masquerading’, and is used by the majority of domestic and small business Internet users today.
Its fundamental weakness in that machines hidden behind a global address cannot be ‘seen’ from the Internet, breaking the end-to-end principle of the Internet i.e. transparent end-to-end connectivity.
Moving towards IPv6
The bigger address space IPv6 offers is the most obvious enhancement it has over IPv4. IPv4 supports 232 addresses, but IPv6 has 128-bit addressing that supports 2128 (about 3.4×1038) addresses. Being allocated a full IP allows unconstrained IP connectivity for today's IP-based machines as well mobile devices such as PDAs and mobile phones.
The transition from IPv4 to IPv6 is already taking place. The 2008 Olympic Games was the first major world event to have a presence on the IPv6 Internet, and all network operations of the Games were conducted using IPv6. However, there are still major concerns over the current deployment rate of IPv6 – with Europe in particular being a notable laggard.
There are publicly and privately funded projects aimed at promoting the deployment of IPv6. For example The European Commission has announced, as a part of its i2010 initiative, an action plan to see IPv6 widely deployed in Europe by 2010.2
Challenges in upgrading
For organisations moving to IPv6, the challenge lies in the transition strategy. Currently, organisations seeking to introduce IPv6 into their network infrastructure operate in a dual-stack environment; supporting IPv4 and IPv6 concurrently for a period of time.
Tunnelling and protocol translation are the other known strategies. Tunnelling encapsulates IPv6 within IPv4 packets in order to send it over a backbone that does not support the newer version. Protocol translation on the other hand, involves network devices translating traffic from IPv4 to IPv6 (or vice and versa). Both tend to be chosen as a last resort, as the latter defeats the notion of
end-to-end network communications and security by causing problems with NAT, and highly constrains the use of IP-addressing, while the former requires a large expenditure to be made on upgrading the organisation’s security and network management infrastructure.
Deciding on the option for you
An organisation’s IPv6 strategy should ideally be borne out of its own unique business case, as well as a consideration of its network infrastructure. High on the list of considerations should be the inter-relationships with other infrastructure programmes and incorporating the transition plan into the overall IT budget.
Organisations considering the transition should be mindful of considering issues relating to security, interoperability, and performance, as well as the true costs associated with developing these detailed plans. Organisations currently running on IPv4 infrastructure and applications should start planning for migration, before internal forces or third parties necessitate the transition due to a critical shortage of IPv4 addresses.
1 The Times, 25 September 2008
2 http://ec.europa.eu/information_society/newsroom/cf/itemdetail.cfm?item_id=4133