Moving from IPv4 to IPv6 – What needs to happen

The world is running out of IPv4 addresses – the familiar 32-bit numerical addresses used to represent the identity of every Internet-connected device in the world.

The African Network Information Centre (AFRINIC) is one of the only regional Internet registries that has not completely run out of IPv4 addresses, and it is quickly approaching total depletion.

Computers, smartphones, and other connected devices communicate over the Internet using Transmission Control Protocol/Internet Protocol (TCP/IP), which routes information between connected devices using their IP addresses.

An IP address represents your device on the Internet, allowing others to send you information and letting you send information to other devices.

Websites, servers, routers, web applications, and smartphones all have an IP address which allows them to send and receive data over the Internet.

IPv4 was deployed in 1983 as a way to ensure every device connected to the Internet could use a unique address. It does this by assigning a 32-bit address to each connected device.

This allows for a maximum of 232 (around 4.3 billion) unique addresses to be assigned. This was more than enough IP address space for 1983, but it has quickly filled up as the number of connected devices increases.

The last free IPv4 address was allocated by the Internet Assigned Numbers Authority (IANA) in February 2011, and while other registries may dynamically allocate and assign IPv4 addresses, the need for a larger IP address space is becoming increasingly apparent.

The answer to this problem is Internet Protocol version 6 (IPv6) – a new version of Internet Protocol which offers an impressive number of available addresses.

Where IPv4 used 32-bit addresses, IPv6 uses 128-bit addresses, which means that instead of just under 4.3 billion addresses, the IPv6 address space can hold 2128 (340 undecillion or 340 trillion trillion trillion) addresses.

IPv6 addresses are denoted differently to IPv4 addresses and are therefore not backwards-compatible with the older protocol.

IPv4 uses dot-decimal notation to denote addresses as a group of four 8-bit decimal numbers, e.g. 100.168.18.31.

IPv6 represents addresses as eight groups of 16-bit hexadecimal numbers separated by colons, e.g. 2001:0db8:85a3:0000:0000:8a2e:0370:7334.

The vast number of IPv6 addresses means that using Network Address Translation (NAT) is unnecessary, as it can support direct addressing instead of masking non-routable addresses behind a single NAT address.

Transition to IPv6

As IPv6 is not backwards-compatible, the first phase of the transition to the new IP address space will require a dual-stack solution where devices and networks support both protocol versions.

However, networks will eventually need to migrate entirely to IPv6 to avoid wasting resources by supporting legacy IP versions.

This means that users, networks, and companies will need to all move towards using the IPv6 address space and drop support IPv4 in future.

While many devices in circulation support IPv6, migrating from IPv4 is still is a significant step.

This migration process may differ depending on your organisation, but the first step for hosting any services is to obtain an IPv6 address block to enable visitors using IPv6 to access your services.

Additionally, you may want to enable IPv6 within your internal network, which will require the upgrade of any legacy devices to support IPv6 as well as an adapted network configuration.

The bulk of the migration process concerns the auditing of network components to ensure that all infrastructure and firmware supports IPv6.

You will also need to allocate the IPv6 address block within your network, define subnets and configure applications such as firewalls to ensure that the migration runs smoothly.

IPv6 migration can be a complex process which depends entirely on the scope of your organisation’s network operations.

If you are looking for a detailed guideline to IPv6 migration, Surfnet has published an outline document which describes the IPv6 migration process to network architects.

Obstacles and migration

To get an idea of the obstacles to IPv6 migration in South Africa, MyBroadband spoke to Cybersmart CTO Laurie Fialkov.

“The biggest obstacle by far is apathy,” Fialkov said.

He said that everyone knows the need to migrate to IPv6 is coming, but there is not much being done to enable migration.

“It is not like the IPv4 space is being switched off, so until such time as your organisation or your clients cannot get to a service or the content that you require because that site/service is only available on the IPv6 address space, you are not really incentivised to do anything.”

“This is exacerbated by the fact that migrating to IPv6 does introduce risk because at the very least you may have to upgrade firmware and you may have to replace legacy routers which don’t nor won’t support IPv6, which may have a significant financial cost,” Fialkov said.

He said that another frustration involved in migration is that it is not possible currently to run purely IPv6, as major services like Skype do not currently support IPv6.

This means that you will need to run a dual-stack (IPv4 and IPv6) network architecture.

“This introduces a whole bunch of complexities, as there, of course, isn’t just one translation mechanism between IPv4 and IPv6,” Fialkov said.

“There are a lot – NAT64, DNS64, ISATAP, 464XLAT – they all have their advantages and disadvantages, and deciding which one is ‘the best’ of course makes the decision to move as opposed to wait and see that much more complex.”

Fialkov predicted that South Africa will only see mass adoption of IPv6 when the IPv4 address space is completely exhausted and companies which still use IPv4 exclusively realise that they cannot onboard any new users.

“Another driver is where a service or site that is only on IPv6 gets viral adoption and forces people to migrate in order to reach that site/service.”

Fialkov said that, currently, there are only a few things that are mandatory for companies to do if they want to be prepared for IPv6 migration:

  1. Put your IT person on a course because IPv6 is much more complicated than IPv4 and you really need to get a handle on the various translation mechanisms.
  2. Do an audit of your devices to ascertain what your risk is with regards to firmware upgrades and what your ultimate financial cost will be should you need to replace devices.

Cybersmart has decided on a DNS64/NAT64 and dualstacking solution for its IPv6 migration.

Laurie Fialkov
Cybersmart CTO Laurie Fialkov

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Moving from IPv4 to IPv6 – What needs to happen