While some common Internet applications already work with IPv6, other software applications may need updates or customisation. The easiest way to port an IPv4 application is to substitute the old IPv4 API references with the new IPv6 APIs using one-to-one mapping. This way, the application will be IPv6-only. While the process may temporarily inconvenience users, it will ensure a smooth transition. As applications get ported to support both IPv4 and IPv6, existing IPv4-only applications can be phased out.

As IPv6 is expected to gradually replace IPv4, the two will need to coexist during the transition. Advanced networks can run both IPv4 and IPv6 concurrently throughout the migration. This means networks can equally support features like quality of service, multicasting and routing.

Many routing and interworking protocols have been established to accommodate the transition to IPv6, including dual-stack, tunnelling and translation standards. With dual-stack, networks receive full support for both IPv4 and IPv6 in routers and hosts. With tunnelling, encapsulation of IPv6 within IPv4 is used to traverse IPv4 networks. Finally, with translation, each protocol allows IPv6-only devices to communicate with IPv4-only devices.

When IPv6 is ready to go, the security infrastructure should be reviewed to ensure access control lists in the network and the firewall cover IPv6 transport traffic. IPv6 can introduce both known and unknown security considerations; therefore, make sure the security measures are updated to address IPv6 concerns.

- Aaron Condon is acting country manager for Extreme Networks Australia and New Zealand.