Internet Protocol version 6 (IPv6) is a replacement for IPv4 that is becoming more frequently used on networked devices. IPv6 is a suite of protocols and standards developed by the Internet Engineering Task Force (IETF) that provides a larger address space than IPv4, additional functionality and security, and resolves IPv4 design issues. You can use IPv6 without affecting IPv4 communications.
IPv6 supports stateful address configuration that is used with a DHCPv6 server, and stateless address configuration, where hosts on a link automatically configure themselves with IPv6 addresses for the link, called link-local addresses.
In IPv6, source and destination addresses are 128 bits (16 bytes) in length. For reference, the 32-bit IPv4 address is represented in dotted-decimal format, divided by periods along 8-bit boundaries. The 128-bit IPv6 address is divided by colons along 16-bit boundaries, where each 16-bit block is represented as a 4-digit hexadecimal number. This is called colon-hexadecimal.
The IPv6 address, 2008:0AB1:0000:1E2A:0123:0045:EE37:C9B4
can be simplified by removing the leading zeros within each 16-bit block, as long as each block has at least one digit. When suppressing leading zeros, the address representation becomes: 2008:AB1:0:1E2A:123:45:EE37:C9B4
When addresses contain contiguous sequences of 16-bit blocks set to zeros, the sequence can be compressed to
::
, a double-colon. For example, the link-local address of 2008:0:0:0:B67:89:ABCD:1234
can be compressed to 2008::B67:89:ABCD:1234
. The multicast address 2008:0:0:0:0:0:0:2
can be compressed to 2008::2
.
The IPv6 prefix is the part of the address that indicates the bits of the subnet prefix. Prefixes for IPv6 subnets, routes, and address ranges are written as address/prefix-length, or CIDR notation. For example, 2008:AA::/48
and 2007:BB:0:89AB::/64
are IPv6 address prefixes.
Secure Mobile Access supports IPv6 in the following areas: