Ipv6 Addresses And Prefixes; Address Types - Allied Telesis SwitchBlade x908 Series Software Reference Manual

IPv6 Addresses and Prefixes

IPv6 addresses are hexadecimal, and are made up of eight pairs of octets separated by colons.
An example of a valid address is fe80:0000:0000:0000:0260:0000:97ff:64aa. In the interests of
brevity, addresses can be abbreviated in two ways:
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Like IPv4 addresses, a proportion of the leftmost bits of the IPv6 address can be used to
indicate the subnet, rather than a single node. This part of the address is called the prefix.
Prefixes provide the equivalent functionality to a subnet mask in IPv4, allowing a subnet to be
addressed, rather than a single node. If a prefix is specified, the IPv6 address is followed by a
slash and the number of bits that represent the prefix. For example, 3ffe::/16 indicates that the
first 16 bits (3ffe) of the address 3ffe:0:0:0:0:0:0:0 represent the prefix.
Like IPv4 addresses, IPv6 addresses are attached to interfaces.

Address types

IPv6 supports the following address types:
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Unicast addresses
A unicast address is attached to a single interface and delivers packets only to that interface.
The following special addresses have been defined:
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Multicast addresses
IPv6 multicast addresses provide the equivalent functionality to broadcast addresses in IPv4.
Broadcast addresses are not supported in IPv6. A multicast address identifies a group of
interfaces, and packets are sent to all interfaces in that group.
C613-50007-01 REV B
Leading zeros can be omitted, so this address can be written as fe80:0:0:0:260:0:97ff:64aa.
Consecutive zeros can be replaced with a double colon, so this address can be written as
fe80::260:0:97ff:64aa. Note that a double colon can replace any number of consecutive
zeros, but an address can contain only one double colon.
Unicast
Multicast
Anycast
IPv4-compatible and IPv4-mapped addresses. IPv4-compatible addresses are used to
tunnel IPv6 packets across an IPv4 network. IPv4-mapped addresses are used by an IPv6
host to communicate with an IPv4 host. The IPv6 host addresses the packet to the
mapped address.
Link-local addresses, which can be used on the local network that the interface is attached
to. The link-local prefix is fe80::/10. Different interfaces on a device may have the same
link-local address.
Site-local addresses, which are used in internal or private networks. These addresses are
analogous to the IPv4 private addresses 10.x.x.x and 192.168.x.x.
The Loopback address, consisting of ::1, which is the equivalent of the IPv4 loopback
address, and allows a host to send packets to itself.
The Unspecified address, consisting of ::, which is the equivalent of the IPv4 unspecified
address, and is used as a source address by hosts during the autoconfiguration process.
Software Reference for SwitchBlade® x908, x900 and x600 Series Switches
TM
AlliedWare Plus Operating System - Software Version 5.3.1
IPv6 Introduction
24.3