Experimental Values In IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP Headers
RFC 4727
Document | Type |
RFC - Proposed Standard
(November 2006; No errata)
Was draft-fenner-iana-exp-2780 (individual in int area)
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Author | Bill Fenner | ||
Last updated | 2015-10-14 | ||
Stream | Internet Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4727 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Jari Arkko | ||
Send notices to | (None) |
Network Working Group B. Fenner Request for Comments: 4727 AT&T Labs - Research Category: Standards Track November 2006 Experimental Values in IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP Headers Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The IETF Trust (2006). Abstract When experimenting with or extending protocols, it is often necessary to use some sort of protocol number or constant in order to actually test or experiment with the new function, even when testing in a closed environment. This document reserves some ranges of numbers for experimentation purposes in specific protocols where the need to support experimentation has been identified, and it describes the numbers that have already been reserved by other documents. Fenner Standards Track [Page 1] RFC 4727 Experimental Values in Headers November 2006 1. Introduction [RFC3692] recommends assigning option numbers for experiments and testing. This document documents several such assignments for the number spaces whose IANA considerations are documented in [RFC2780]. This document generally follows the form of [RFC2780]. When using these values, carefully consider the advice in Sections 1 and 1.1 of [RFC3692]. It is not appropriate to simply select one of these values and hard code it into a system. Note: while [RFC3692] says that it may not be necessary to allocate values for UDP and TCP ports, Sections 6 and 7.1 explicitly reserve ports for this purpose to avoid any possible conflict. 2. Fields in the IPv4 Header The IPv4 header [RFC0791] contains the following fields that carry values assigned by the IANA: Version, Type of Service, Protocol, Source Address, Destination Address, and Option Type. 2.1. IP Version Field in the IPv4 Header The Version field in IPv4 packets is always 4. 2.2. IPv4 Type of Service Field [RFC2474] defines Pool 2 (all code points xxxx11, where 'x' refers to either '0' or '1') as Experimental/Local Use, so no additional code points should be needed. The Explicit Congestion Notification (ECN) field [RFC3168] has no free code points to assign. 2.3. IPv4 Protocol Field [RFC3692] allocates two experimental code points (253 and 254) for the IPv4 Protocol field. 2.4. IPv4 Source and Destination Addresses 2.4.1. IPv4 Unicast No experimental IPv4 addresses are defined. For certain experiments, the address ranges set aside for Private Internets in [RFC1918] may be useful. It is not appropriate to use other special-purpose IPv4 addresses [RFC3330] for experimentation. Fenner Standards Track [Page 2] RFC 4727 Experimental Values in Headers November 2006 At the time of this writing, some Internet Registries have policies allowing experimental assignments from number spaces that they control. Depending on the experiment, the registry, and their policy, this may be an appropriate path to pursue. 2.4.2. IPv4 Multicast The globally routable group 224.0.1.20 is set aside for experimentation. For certain experiments, the administratively scoped multicast groups defined in [RFC2365] may be useful. This document assigns a single link-local scoped group, 224.0.0.254, and a single scope-relative group, 254. 2.5. IPv4 Option Type Field This document assigns a single option number, with all defined values of the "copy" and "class" fields, resulting in four distinct option type codes. See Section 8 for the assigned values. 3. Fields in the IPv6 Header The IPv6 header [RFC2460] contains the following fields that carry values assigned from IANA-managed name spaces: Version, Traffic Class, Next Header, Source and Destination Address. In addition, the IPv6 Hop-by-Hop Options and Destination Options extension headers include an Option Type field with values assigned from an IANA- managed name space. The IPv6 Routing Header contains a Type field for which there is not currently an explicit IANA assignment policy. 3.1. IP Version Field in the IPv6 Header The Version field in IPv6 packets is always 6. 3.2. IPv6 Traffic Class Field [RFC2474] defines Pool 2 (all code points xxxx11, where 'x' refers to either '0' or '1') as Experimental/Local Use, so no additional code points should be needed. The ECN field [RFC3168] has no free codeShow full document text