Allied Telesis AT-S95 WEB - Manual (Page 25)

Configuring IPv6
Page 25
Chapter 3. Configuring IPv6
The device functions as an IPv6 compliant Host, as well as an IPv4 Host (also known as dual stack). This allows
device operation in a pure IPv6 network as well as in a combined IPv4/IPv6 network.
The primary change from IPv4 to IPv6 is the length of network addresses. IPv6 addresses are 128 bits long,
whereas IPv4 addresses are 32 bits; allowing a much larger address space.
This section contains information on configuring the Internet Protocol Version 6 (IPv6) of the device.
IPv6 Syntax
The 128-bit IPv6 address format is divided into eight groups of four hexadecimal digits. Abbreviation of this format
is done by replacing a group of zeros with double colons. The IPv6 address representation can be further
simplified by suppressing the leading zeros.
IPv6 Prefixes
While Unicast IPv6 addresses written with their prefix lengths are permitted, in practice their prefix lengths are
always 64 bits and therefore are not required to be expressed. Any prefix that is less than 64 bits is a route or
address range that is summarizing a portion of the IPv6 address space.
For every assignment of an IP address to an interface, the system runs the Duplicate Address Detection algorithm
to ensure uniqueness.
An intermediary transition mechanism is required for IPv6-only nodes to communicate with IPv6 nodes over an
IPv4 infrastructure. The tunneling mechanism implemented is the Intra-Site Automatic Tunnel Addressing
Protocol (ISATAP). This protocol treats the IPv4 network as a virtual IPv6 local-link, with each IPv4 address
mapped to a Link Local IPv6 address.
This section describes the following topics:
• Defining IPv6 Interfaces
• Defining the IPv6 Default Gateway
• Configuring Tunnels
• Defining IPv6 Neighbors
Defining IPv6 Interfaces
The IPv6 Interface Page provides parameters for defining an IPv6 interface. When an interface is selected on a
locally connected device, the system creates an IP interface and automatically configures a Link Local address on
the interface. The automatically generated Link Local IPv6 address cannot be removed.
In addition to the dynamically configured IPv6 interfaces, there are two types of static IP addresses that can be
configured on an IPv6 interface:
• Link Local Address — Defines a Link Local address that is non-routable and used for communication on the
same network only.
• Global Addresses — Defines a globally unique IPv6 address; visible and reachable from different subnets.
To define IPv6 Interfaces:
1. Click System > IPv6 Interface. The IPv6 Interface Page opens.