The Internet Protocol (IP) defines how devices on the internet are addressed so other things can find them to talk to them. Like a house or business address, the addressing scheme is set up in a hierarchical fashion to simplify the routing of communication. There are two major addressing schemes – two versions of the Internet Protocol – in use today: IPv4 and IPv6.
IPv6 is the next generation Internet Protocol which is in the process of replacing the current version, IPv4. It was designed and began deployment decades ago, but the recent worldwide depletion of available IPv4 address space has brought it to the forefront. The IPv4 addressing structure only allowed for a maximum of ~4.3 billion (2^32) unique addresses.
When IPv6 was initially deployed, it was expected that IPv4 addresses would be exhausted by the early 2010s. A technique known as Network Address Translation (NAT) became an essential tool in conserving global address space in the face of IPv4 exhaustion. NAT allows one Internet-routable IP address to be used for an entire private network. For example, at home you probably receive one public IP address from your Internet Service Provider (although some service providers are increasingly using an alternative method of “nested NAT” within their network). Every device in your home (mobile phones, laptops, PCs, game consoles, etc.) “masquerades” behind this single public IP address, only consuming one of the 4.3 billion IPv4 addresses, despite the 10-20 internet-connected devices in many homes.
IPv6 widens the available internet address space by many orders of magnitude, expanding the current 32 bit IPv4 address to 128 bits. Thus IPv6 provides for a maximum of 3.4×10^38 (340 trillion trillion trillion) unique IP addresses, or about 47 octillion unique addresses for every person on the planet. Ideally, a casual internet user will not notice a shift to IPv6 as most devices produced recently are already IPv6 capable, and many of the major internet providers are already IPv6-enabled. As the remainder of the IPv4 address space has finally been exhausted in recent years, there is a renewed emphasis on fully enabling IPv6 to allow the continued expansion of the internet. It is worth noting that IPv4 addresses are not going to stop working any time soon. The internet will continue to support both, and over time the proportion of IPv4 to IPv6 will invert.
UW-IT encourages the University’s IT community to begin familiarizing themselves with IPv6 and how it may impact future networking requirements, as there could be many considerations for the IT professional operating in the IPv6 environment.
- IPv6 address space can be requested alongside an existing IPv4 subnet (“dual stack”) or independently on it’s own. If an IPv6 subnet is requested, the assigned block will be from one of two larger allocations. One allocation is fully publicly accessible, similar to getting public IPv4 space. The other allocation, while also being publicly addressed, will be routed through a stateful firewall filter to allow all outbound and only established inbound traffic. This provides for a similar experience to the RFC1918 space (p172 and 10net) allocated on campus using NAT. The intent is to match the level of protections to the established IPv4 networks.
- UW-IT supports IPv6 address assignment via Stateless Autoconfiguration, also known as SLAAC. With SLAAC assignments the router announces a local prefix, and each host automatically picks an address within that prefix. Customers can also choose not to have the router advertise any prefix and assign addresses manually. When requesting IPv6 address assignment, please specify “without SLAAC” if you wish to assign addresses manually.
- All address assignments will be /64 blocks. No justification is necessary to receive a /64 for any given network. The router’s IP address will always be the first address in the /64, i.e. 2607:4000:100::1 with the next two addresses reserved for VRRP operation.
- DHCP address assignment for IPv6 addresses will not be supported in this phase of IPv6 deployment. The DHCPv6 standard was slow to be finalized and ratified, and not every common operating system yet supports DHCPv6. As adoption of the standard becomes more widespread UW-IT will establish and support IPv6 addressing via DHCP. Customers can set up a DHCPv6 server on their own subnet if desired.
- Wireless, Medicine, and Resident Hall networks are not being offered IPv6 at this time.
Below is a series of informative links. The top link connects to a page entitled ‘Customer problems that could occur’ (right side of the page under ‘How do I prepare’). This may help provide you with some information on the types of issues that are likely to crop up in your experimentation.