38 IPV6 BASICS CONFIGURATIONWhen configuring IPv6 basics, go to these sections for information you areinterested in:■ “IPv6 Overview” on page 499■ “IPv6 Basics Configuration Task List” on page 508■ “Configuring Basic IPv6 Functions” on page 508■ “Configuring IPv6 NDP” on page 510■ “Configuring PMTU Discovery” on page 513■ “Configuring IPv6 TCP Properties” on page 514■ “Configuring ICMPv6 Packet Sending” on page 514■ “Configuring IPv6 DNS” on page 515■ “Displaying and Maintaining IPv6 Basics Configuration” on page 516■ “IPv6 Configuration Example” on page 517■ “Troubleshooting IPv6 Basics Configuration” on page 520n The term “router” or the router icon in this document refers to a router in ageneric sense or a Layer 3 Ethernet switch running a routing protocol.IPv6 Overview Internet Protocol Version 6 (IPv6), also called IP next generation (IPng), wasdesigned by the Internet Engineering Task Force (IETF) as the successor to InternetProtocol Version 4 (IPv4). The significant difference between IPv6 and IPv4 is thatIPv6 increases the IP address size from 32 bits to 128 bits.This section covers thefollowing:■ “IPv6 Features” on page 499■ “Introduction to IPv6 Address” on page 501■ “Introduction to IPv6 Neighbor Discovery Protocol” on page 504■ “IPv6 PMTU Discovery” on page 507■ “Introduction to IPv6 DNS” on page 507■ “Protocols and Standards” on page 508IPv6 Features Header format simplificationIPv6 cuts down some IPv4 header fields or move them to the IPv6 extensionheaders to reduce the length of the basic IPv6 header. IPv6 uses the basic headerwith a fixed length, thus making IPv6 packet handling simple and improving theforwarding efficiency. Although the IPv6 address size is four times that of IPv4
