Alcatel-Lucent 6850-48 网络指南
IPv6 Overview
Configuring IPv6
page 26-6
OmniSwitch AOS Release 6 Network Configuration Guide
September 2009
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.
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.
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.
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.
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.
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.
multicast addressing capabilities.
IPv6 address types are identified by the high-order bits of the address, as shown in the following table:
Note that anycast addresses are unicast addresses that are not identifiable by a known prefix.
Address Type
Binary Prefix
IPv6 Notation
Unspecified
00...0 (128 bits)
::/128
Loopback
00...1 (128 bits)
::1/128
Multicast
11111111
FF00::/8
Link-local unicast
1111111010
FE80::/10
Unique Local IPv6 uni-
cast
cast
11111100
FC00::/7
Global unicast
everything else