3Com Switch 8800 Advanced Software V5 Configuration Guide

220 CHAPTER 23: IPV6 BASICS CONFIGURATION
The working procedure of the PMTU discovery is as follows:
1 The source host uses its MTU to fragment packets and then sends them to the
destination host.
2 If the MTU supported by the forwarding interface is less than the packet size, the
forwarding device will discard the packet and return an ICMPv6 error packet
containing the interface MTU to the source host.
3 After receiving the ICMPv6 error packet, the source host uses the returned MTU to
fragment the packet again and then sends it.
4 Step 2 to step 3 are repeated until the destination host receives the packet. In this
way, the minimum MTU of all links in the path from the source host to the
destination host is determined.
Introduction to IPv6 DNS In the IPv6 network, a domain name system (DNS) supporting IPv6 converts
domain names into IPv6 addresses, instead of IPv4 addresses.
However, just like an IPv4 DNS, an IPv6 DNS also covers static domain name
resolution and dynamic domain name resolution. The function and
implementation of these two types of domain name resolution are the same as
those of an IPv4 DNS. For details, refer to
“DNS Overview” on page 745.
Usually, the DNS server connecting IPv4 and IPv6 networks not only contain A
records (IPv4 addresses), but also AAAA records (IPv6 addresses). The DNS server
can convert domain names into IPv4 addresses or IPv6 addresses. In this way, the
DNS server implements the functions of both IPv6 DNS and IPv4 DNS.
Protocols and Standards Protocols and standards related to IPv6 include:
■ RFC 1881: IPv6 Address Allocation Management
■ RFC 1887: An Architecture for IPv6 Unicast Address Allocation
■ RFC 1981: Path MTU Discovery for IP version 6
■ RFC 2375: IPv6 Multicast Address Assignments
■ RFC 2460: Internet Protocol, Version 6 (IPv6) Specification.
■ RFC 2461: Neighbor Discovery for IP Version 6 (IPv6)
■ RFC 2462: IPv6 Stateless Address Autoconfiguration
■ RFC 2463: Internet Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification
■ RFC 2464: Transmission of IPv6 Packets over Ethernet Networks
■ RFC 2526: Reserved IPv6 Subnet Anycast Addresses
■ RFC 3307: Allocation Guidelines for IPv6 Multicast Addresses
■ RFC 3513: Internet Protocol Version 6 (IPv6) Addressing Architecture
■ RFC 3596: DNS Extensions to Support IP Version 6