Ipv6 Addressing - Alcatel-Lucent OmniSwitch 6850-48 Network Configuration Manual

IPv6 Overview

IPv6 Addressing

One of the main differences between IPv6 and IPv4 is that the address size has increased from 32 bits to
128 bits. Going to a 128-bit address also increases the size of the address space to the point where running
out of IPv6 addresses is not a concern.
The following types of IPv6 addresses are supported:
Link-local—A link-local address is a private unicast address that identifies an interface or device on the
local network. This type of address allows communication with devices and/or neighboring nodes that are
attached to the same physical link. Note that when the communication is between two nodes that are not
attached to the same link, both nodes must have a configured global unicast address. Routing between
link-local addresses is not available because link-local addresses are not known or advertised to the
general network.
Unicast—Standard unicast addresses, similar to IPv4.
Unique Local IPv6 Unicast—IPv6 unicast address format that is globally unique and intended for local
communications, usually inside of a site. These addresses are not expected to be routable on the global
Internet.
Multicast—Addresses that represent a group of devices. Traffic sent to a multicast address is delivered to
all members of the multicast group.
Anycast—Traffic that is sent to this type of address is delivered to one member of the anycast group. The
device that receives the traffic is usually the one that is easiest to reach as determined by the active rout-
ing protocol.
Note. IPv6 does not support the use of broadcast addresses. This functionality is replaced using improved
multicast addressing capabilities.
IPv6 address types are identified by the high-order bits of the address, as shown in the following table:
Address Type
Unspecified
Loopback
Multicast
Link-local unicast
Unique Local IPv6 uni-
cast
Global unicast
Note that anycast addresses are unicast addresses that are not identifiable by a known prefix.
page 26-6
Binary Prefix
00...0 (128 bits)
00...1 (128 bits)
11111111
1111111010
11111100
everything else
OmniSwitch AOS Release 6 Network Configuration Guide
IPv6 Notation
::/128
::1/128
FF00::/8
FE80::/10
FC00::/7
Configuring IPv6
September 2009