Introduction To Ipv6 Dns; Protocols And Standards - 3Com 4510G Configuration Manual

The path MTU (PMTU) discovery mechanism is to find the minimum MTU of all links in the path from
the source to the destination.
Figure 13-5 Working procedure of PMTU discovery
The working procedure of the PMTU discovery is as follows:
1) The source host uses its MTU to send packets to the destination host.
2) If the MTU supported by a forwarding interface is smaller 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 send packets
to the destination.
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

IPv6 Domain Name System (DNS) is responsible for translating domain names into IPv6 addresses,
instead of IPv4 addresses.
Like IPv4 DNS, IPv6 DNS also involves 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 IPv4 DNS. For details, refer to DNS Configuration in the IP Services Volume.
Usually, the DNS server connecting IPv4 and IPv6 networks not only contains 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
Figure 13-5 shows the working procedure of PMTU discovery.
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