Request for Comments

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For the Wikipedia process, see Wikipedia:Requests for comment.

In internetworking and computer network engineering, Request for Comments (RFC) documents are a series of memoranda encompassing new research, innovations, and methodologies applicable to Internet technologies.

Through the Internet Society, engineers and computer scientists may publish discourse in the form of an RFC memorandum, either for peer review or simply to convey new concepts, information, or (occasionally) engineering humor. The Internet Engineering Task Force (IETF) adopts some of the proposals published in RFCs as Internet standards.

1 RFC production and evolution
2 History
3 Obtaining RFCs
4 Status
5 See also
6 External links
7 References

[edit] RFC production and evolution

The RFC Editor issues each RFC document with a unique serial number. Once issued a numerical identifier and published, an RFC is never rescinded or modified; if the document requires amendments, the authors publish a revised document; therefore, some RFCs make others obsolete, or "deprecated". Together, the serialized RFCs compose a continuous historical record of the evolution of Internet standards.

Note that the term "RFC" is not unique to this series. Several other organizations have published documents using the term "RFC". However, this is by far the best-known "RFC" series on the Internet.

The RFC production process differs from the standardization process of formal standards organizations such as ANSI. Internet technology experts may submit an Internet Draft without support from an external institution. Standards-track RFCs are published with approval from the IETF, and are usually produced by experts participating in working groups, which first publish an Internet Draft. This approach facilitates initial rounds of peer review before documents mature into RFCs.

The RFC tradition of pragmatic, experience-driven, after-the-fact standards-authorship accomplished by individuals or small working groups has important advantages over the more formal, committee-driven process typical of ANSI or ISO.

Emblematic of some of these advantages is the existence of a flourishing tradition of joke RFCs. Usually at least one a year is published, usually on April Fools' Day.

Most RFCs use a common set of keywords/phrases such as "MUST" and "NOT RECOMMENDED" (as defined by RFC 2119), an Augmented Backus-Naur form (ABNF) (as defined by RFC 4234) as a metalanguage, and simple text-based formatting, in order to keep the RFCs consistent and easy to understand.

For more details about RFCs and the RFC process, see RFC 2026, "The Internet Standards Process, Revision 3".

[edit] History

The inception of the RFC format occurred in 1969 as part of the seminal ARPANET project. Today, it is the official publication channel for the IETF, the Internet Architecture Board (IAB), and — to some extent — the global community of computer network researchers in general.

The authors of the first RFCs typewrote their work and circulated hard copies among the ARPA researchers. Unlike the modern RFCs, many of the early RFCs were requests for comments. The RFC leaves questions open and is written in a less formal style. This less formal style is now typical of Internet Draft documents, the precursor step before being approved as an RFC.

In December of 1969, researchers began distributing new RFCs via the now-operational ARPANET. RFC 1, entitled "Host Software", was written by Steve Crocker of the University of California, Los Angeles (UCLA), and published on April 7, 1969. Although written by Steve Crocker, the RFC emerged from an early working group discussion between Steve Crocker, Steve Carr, Jeff Rulifson. (The document lists Bill Duvall as having attended only the final working group meeting prior to publication.)

In RFC 3, which first defined the RFC series, Steve Crocker started attributing the RFC series to the "Network Working Group". This group seems never to have had a formal existence, being rather defined as "this group of people", but the attribution remains on RFCs to this day.

Many of the subsequent RFCs of the 1970s also came from UCLA, not only because of the quality of the scholarship, but also because UCLA was one of the first Interface Message Processors (IMPs) on ARPANET.

Douglas Engelbart's Augmentation Research Center (ARC) at Stanford Research Institute was another of the four first ARPANET nodes, as well as the first Network Information Centre, and (as noted by the sociologist Thierry Bardini) the source of a large number of early RFCs.

From 1969 until 1998, Jon Postel served as the RFC editor. Following the expiration of the original ARPANET contract with the U.S. federal government, the Internet Society (acting on behalf of the IETF) contracted with the Networking Division of the USC Information Sciences Institute to assume the editorship and publishing responsibilities (under the direction of the IAB). Jon Postel continued to serve as the RFC Editor until his death. Later, Bob Braden has taken over the role of project lead, while Joyce K. Reynolds has continued to be part of the team.

[edit] Obtaining RFCs

The official source for RFCs on the World Wide Web is the RFC Editor. Unofficially, they are obtainable from a multitude of mirrors accessible via the HyperText Transfer Protocol, anonymous FTP, the gopher protocol, and other prominent application layer protocols.

One may retrieve almost any individual, published RFC like RFC 3700 via the following URL example: http://www.rfc-editor.org/rfc/rfc3700.txt

Every RFC is available as ASCII text, but may also be available in other file formats; however, as of 2006 the definitive version of any standards-track specification is the ASCII version. Note that RFC 1119 is not on standards track.

For easy access on the meta data of an RFC including abstract, keywords, author(s), publication date, errata, status, and especially later updates or replacements in human readable format the RFC Editor site offers a search form with many features. A redirection sets some efficient parameters, example: http://purl.net/net/rfc/3700

[edit] Status

Not every RFC is a standard. Only the IETF represented by the IESG can approve standards track RFCs, further divided into proposed (PS), draft (DS), and full Internet Standards (STD). The STD subseries has its own numbers; as of 2006 STD 1 is RFC 3700. Some STDs form small sets of more than one related RFC.

An experimental RFC can be an IETF document or an individual submission to the RFC Editor. In theory it is indeed experimental; in practice some documents are not promoted on standards track because there are no volunteers for the procedural details.

An informational RFC can be nearly anything from April 1st jokes over proprietary protocols up to widely recognized essential RFCs like RFC 1591. Some informational RFCs form the subseries "for your information" (FYI). While rarely added to today some old FYIs are still interesting, for example FYI 18 aka RFC 1983, the "Internet User's Glossary". FYI 17 or "The Tao of IETF" is now RFC 4677, published in 2006.

A historic RFC is one that is obsoleted by a newer version, documents a protocol that is not considered interesting in the current Internet, or has been removed from the standards track for other reasons. Some obsolete RFCs are not classified as historic, because the "Internet Standards Process" generally does not allow normative references from a standards track RFC to another RFC with lower status. Also, not many people are interested in working through the required procedural details to get RFCs classified as historic and update all RFCs normatively depending on it.

Status unknown is used for very old RFCs, when it is unclear which status it would get if published today. In some cases those RFCs wouldn't be published at all – the early RFCs were often what the name says, simple "Requests for Comments" not intended to specify a protocol, administrative procedure, or anything else the RFC series is used for today.

The best current practice (BCP) subseries collects administrative documents and other texts which are considered as official rules and not only informational, but which do not affect over the wire data. The border between standards track and BCP is often unclear. If a document only affects the "Internet Standards Process" aka BCP 9 or IETF administration, it is clearly a BCP. If it only defines rules and regulations for IANA registries it is less clear; most of these documents are BCPs, but some are on standards track.

The BCP series also covers technical recommendations for how to practice Internet standards; for instance the recommendation to use source filtering to make DoS attacks harder (RFC 2827: "Network Ingress Filtering: Defeating Denial of Service Attacks which employ IP Source Address Spoofing") is BCP 38.