Alcatel-Lucent 6850-48 网络指南

Configuring IPv6

IPv6 Overview

OmniSwitch AOS Release 6 Network Configuration Guide

page 26-5

IPv6 provides the basic functionality that is offered with IPv4 but includes the following enhancements 
and features not available with IPv4:

• Increased IP address size—IPv6 uses a 128-bit address, a substantial increase over the 32-bit IPv4 

address size. Providing a larger address size also significantly increases the address space available, 
thus eliminating the concern over running out of IP addresses. See 

more information.

• Autoconfiguration of addresses—When an IPv6 interface is created or a device is connected to the 

switch, an IPv6 link-local address is automatically assigned for the interface and/or device. See 

 for more information.

• Anycast addresses—A new type of address. Packets sent to an anycast address are delivered to one 

member of the anycast group.

• Simplified header format—A simpler IPv6 header format is used to keep the processing and band-

width cost of IPv6 packets as low as possible. As a result, the IPv6 header is only twice the size of the 
IPv4 header despite the significant increase in address size.

• Improved support for header options—Improved header option encoding allows more efficient 

forwarding, fewer restrictions on the length of options, and greater flexibility to introduce new options.

• Security improvements—Extension definitions provide support for authentication, data integrity, and 

confidentiality.

• Neighbor Discovery protocol—A protocol defined for IPv6 that detects neighboring devices on the 

same link and the availability of those devices. Additional information that is useful for facilitating the 
interaction between devices on the same link is also detected (e.g., neighboring address prefixes, 
address resolution, duplicate address detection, link MTU, and hop limit values, etc.).

This implementation of IPv6 also provides the following mechanisms to maintain compatibility between 
IPv4 and IPv6:

• Dual-stack support for both IPv4 and IPv6 on the same switch.

• Configuration of IPv6 and IPv4 interfaces on the same VLAN.

• Tunneling of IPv6 traffic over an IPv4 network infrastructure.

• Embedded IPv4 addresses in the four lower-order bits of the IPv6 address.

The remainder of this section provides a brief overview of the new IPv6 address notation, autoconfigura-
tion of addresses, and tunneling of IPv6 over IPv4.