|
An IPv6 transition mechanism is a technology that facilitates the transitioning of the Internet from the Internet Protocol version 4 (IPv4) infrastructure in use since 1981 to the successor addressing and routing system of Internet Protocol Version 6 (IPv6). As IPv4 and IPv6 networks are not directly interoperable, transition technologies are designed to permit hosts on either network type to communicate with any other host. To meet its technical criteria, IPv6 must have a straightforward transition plan from the current IPv4.〔''RFC 1726 - IPng Technical Criteria''〕 The Internet Engineering Task Force (IETF) conducts working groups and discussions through the IETF Internet Drafts and Requests for Comments processes to develop these transition technologies towards that goal. Some basic IPv6 transition mechanisms are defined in RFC 4213. ==Stateless IP/ICMP Translation== Stateless IP/ICMP Translation (SIIT) translates between the packet header formats in IPv6 and IPv4. The SIIT method defines a class of IPv6 addresses called ''IPv4-translated'' addresses. They have the prefix ''::ffff:0:0:0/96'' and may be written as ''::ffff:0:a.b.c.d'', in which the IPv4 formatted address ''a.b.c.d'' refers to an ''IPv6-enabled'' node. The prefix was chosen to yield a zero-valued checksum to avoid changes to the transport protocol header checksum.〔RFC 2765 - ''Stateless IP/ICMP Translation Algorithm (SIIT)'', E. Normark (February 2000)〕 The algorithm can be used in a solution that allows IPv6 hosts, that do not have a permanently assigned IPv4 address, to communicate with IPv4-only hosts. Address assignment and routing details are not addressed by the specification. SIIT can be viewed as a special case of stateless network address translation. The specification is a product of the NGTRANS IETF working group, and was initially drafted in February 2000 as RFC 2765 by E. Nordmark of Sun Microsystems. RFC 2765 was obsoleted by RFC 6145 in 2011.〔RFC 6145 IP/ICMP Translation Algorithm〕 The address format part of RFC 2765 is defined in RFC 6052.〔RFC 6052 - ''IPv6 Addressing of IPv4/IPv6 Translators''〕 The framework of IPv4/IPv6 translation is defined in RFC 6144.〔RFC 6144 - ''Framework for IPv4/IPv6 Translation''〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「IPv6 transition mechanism」の詳細全文を読む スポンサード リンク
|