Introduction; Overview - Allied Telesis SwitchBlade x908 Series Software Reference Manual

IPv6 Introduction

Introduction

This chapter describes the main features of IPv6, the switch's implementation of IPv6 and how
to configure and operate IPv6 on the switch.
This chapter describes the following IPv6 features:
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Overview

IPv6 is the next generation of the Internet Protocol (IP). It has primarily been developed to
solve the problem of the eventual exhaustion of the IPv4 address space, but also offers other
enhancements. IPv6 addresses are 16 bytes long, in contrast to IPv4's 4 byte addresses. Other
features of IPv6 include:
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24.2
linking together networks that run IPv6.
allowing address autoconfiguration of hosts connected to the switch.
Address structure improvements:
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globally unique addresses with more levels of addressing hierarchy to reduce the size
of routing tables
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autoconfiguration of addresses by hosts
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improved scalability of multicast routing by adding a "scope" field to multicast
addresses
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a new type of address, the "anycast address", which sends packets to any one of a
group of devices
Removes the need for packet fragmentation en-route, by dynamic determination of the
largest packet size that is supported by every link in the path. A link's MTU (Maximum
Transmission Unit) must be at least 1280 bytes, compared with 576 bytes for IPv4.
Includes a Traffic Class that allow packets to be labelled with an appropriate priority. If the
network becomes congested, the lowest priority packets are dropped.
Includes Flow labels that indicate to intermediate switches and routers that packets are
part of a flow, and that a particular flow requires a particular type of service. This feature
enables, for example, real-time processing of data streams. It also increases routing speed
because the forwarding router need only check the flow label, not the rest of the header.
The handling indicated by the flow label can be done by the IPv6 Hop-by-Hop header, or
by a separate protocol such as RSVP.
Mandatory authentication and data integrity protocols through IPsec. IPsec is optional in
IPv4.
Software Reference for SwitchBlade® x908, x900 and x600 Series Switches
TM
AlliedWare Plus Operating System - Software Version 5.3.1 C613-50007-01 REV B