Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 669)

IPv6 Introduction
Software Reference for x310 Series Switches
C613-50046-01 REV A AlliedWare Plus TM Operating System - Version 5.4.4C 26.3
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 2001:0db8:0000:0000:0260:0000:97ff:64aa. In
the interests of brevity, addresses can be abbreviated in two ways:
■ Leading zeros can be omitted, so this address can be written as
2001:db8:0:0:260:0:97ff:64aa.
■ Consecutive zeros can be replaced with a double colon, so this address can be written
as 2001:db8::260:0:97ff:64a. Note that a double colon can replace any number of
consecutive zeros, but an address can contain only one double colon.
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, 2001::/
16 indicates that the first 16 bits (2001) of the address 2001:0:0:0:0:0:0:0 represent the
prefix.
Like IPv4 addresses, IPv6 addresses are attached to interfaces.
Address types
IPv6 supports the following address types:
■ Unicast
■ Multicast
■ Anycast
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:
■ 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 can be used on the local network on which the interface is
attached. The link-local prefix is fe80::/10. Different interfaces on a device may have
the same link-local address. The switch will automatically generate a link-local address
for all interfaces that are using IPv6. Commands entered to configure link-local
addresses that match any automatically generated link-local addresses by the switch
will not be executed.
Enter the show ipv6 interface command to display automatically generated link-local
addresses not shown in the running-config. Automatically generated link-local
addresses contain the last six hexadecimal numbers of the MAC address for a given
interface.