About IPv6

IPv6 example address:


There are 280, or 1,208,925,819,614,629,174,706,176 IPv6 addresses in one /48.

IPv6 addresses are usually shown as sequences of hexadecimal digits, separated by a colon character ( : ). Each group is up to four hexadecimal digits long, and each address is made of up to eight groups.

Since IPv6 addresses are so long, this notation allows for compression, omitting the first continuous zero-parts to be a single :: sequence, and removing any leading zeros from any group.

IPv6 Features

  • Flexibility
  • Increased networking efficiency
    • Auto-configuration and plug-and-play will eliminate the need for manual connections and the requirement of additional applications or hardware
    • Embedded security
  • Better packet structure (more hierarchical)

Why was IPv6 developed?

IPv6 was developed to accommodate the dramatic growth of the Internet and subsequent depletion of IPv4. IPv6 is also a redesign and modernization of the IP structure.

The lifespan of IPv4 has been increased to some extent, with the implementation of a handful of methods used to increase network efficiency and slow the rate of exhaustion:

  • Network Address Translation (NAT) enables IPv4 addresses that are no longer in use to be recycled
  • Classless InterDomain Routing (CIDR) increases network efficiency by slowing the growth of the routing tables
  • Dynamic Host Configuration Protocol (DHCP) introduced temporary assignments

However, as more devices require a constant connection, the increased need for bandwidth and the overall growth of the number of networks worldwide has resulted in the depletion of IPv4.

Benefits of 128-bit addresses

  • Room for many levels of structured hierarchy and routing aggregation
  • Easier address management and delegation than IPv4
  • Easy address auto-configuration
  • Ability to deploy end-to-end IPsec (NATs removed as unnecessary)
  • Expanded addressing capabilities

About prefixes

In terms of Internet addressing, a prefix is a variable length quantity, depending on how much Internet address space is being considered.

Both IPv4 and IPv6 addresses are also referred to as ‘prefixes’ of a given length. This is because the Internet routing system works on prefixes, which are sets of Internet addresses that are one consistent group of sources or destinations. In short, a prefix serves as identification for the organization using those addresses.

Prefixes are analogous to tree branches: shorter prefixes are closer to the central branch, and all sub-branches are contained inside the covering (short) prefix. Blocks of Internet addresses are distributed and divided into sub-blocks. These sub-blocks can be represented by the smaller set of prefixes that describe them. Contiguous address blocks are sets of addresses that ‘run together’ as part of the more central, shorter prefix.