ChorusOS 5.0 System Administrator's Guide

IPv4 to IPv6 Transition Process

When transitioning from IPv4 to IPv6, it is important to ensure that all existing hosts and routers that still operate on the network at any one time, can support IPv4-only operations. This is to reduce the risk of problems in the event of dual stack nodes, hosts and routers (those that can support both IPv4 and IPv6 operations) sending tasks through IPv4-only nodes. More information is contained in "Transitioning From IPv4 to IPv6" in System Administration Guide, Volume 3

Standardized Transition Tools

The Internet Engineering Task Force, (IETF) specification for advising companies making the transition from IPv4 to IPv6 is the RTF 1933 specification. For transitioning, this document sets out these transition mechanisms:

Configuring Name Services

A dual node must determine if the peer can support IPv6 or IPv4 to know which IP version to use when transmitting. Controlling what information goes in the name service accomplishes this. You define an IPv4 node's IP address and the IPv6 node's IP address in the name service. Thus, a dual node has both addresses in the name service.

However, the presence of an IPv6 address in the name service also signifies that the node is reachable, using IPv6 from all nodes that get information from that name service. This is no different than in IPv4 where some operations depend on there being only IPv4 addresses for nodes that can be reached using IPv4. When no reachability exists in IPv4 the name service must be partitioned so that IPv4 addresses are visible only where they are reachable.

The protocol used to access the name service is independent of the type of address that can be retrieved from the name service. This name service support, coupled with dual stacks, allows a dual node to use IPv4 when communicating with IPv4-only nodes and use IPv6 when communicating with IPv6 nodes, provided that there is an IPv6 route to the destination.

IPv6 Related Processes

Processes and procedures for ChorusOS networking are enhanced by the introduction of Plug'n'Play Free BSD 4.1 IPv6 and related features. See ip6(7P) and icmp6(7P) man pages for further information.

IP stacks: IPv4 and IPv6

The ChorusOS operating system provides TCP/IP and UDP/IP stacks (POSIX_SOCKETS), both over IPv4 and IPv6.

IPv4 and IPv6 can be used simultaneously.

Consult "Networking" in ChorusOS 5.0 Features and Architecture Overview to see the RFC list of the IPv4 and IPv6 protocols that are supported

See ip6(7P) man page for further information.