TCP/IP Standards and RFCs

The TCP/IP protocol standards that define how the Internet works are managed by an organization called the Internet Engineering Task Force, or IETF. However, the IETF does not impose standards. Instead, it simply oversees the process by which ideas are developed into agreed-upon standards.

An Internet standard is published in a document known as a Request for Comments, or RFC. When a document is accepted for publication, it is assigned an RFC number by the IETF. The RFC is then published. After it is published, an RFC is never changed. If a standard is enhanced, the enhancement is covered in a separate RFC.

At the time of this writing, more than 3,500 RFCs were available from IETF's Web site (www.ietf.org). The oldest RFC is RFC 0001, published in 1969. It describes how the host computers communicated with each other in the original ARPANET. The most recent RFC (as of March 2005) is RFC 4038, an informational document entitled "Application Aspects of IPv6 Transition." Not all RFCs represent Internet standards. The following paragraphs summarize the various types of RFC documents:

Internet Standards Track:
An RCF that represents an Internet standard. Standard Track RFCs have one of three maturity levels, as described in below. An RFC enters circulation with Proposed Standard status, but may be elevated to Draft Standard status and ultimately, to Internet Standard status.

Maturity Levels for Internet Standards Track RFCs

• Proposed Standard
  Proposed standards are generally stable, have resolved known design choices, are believed to be well understood, have received significant community review, and appear to enjoy enough community interest to be considered valuable.
• Draft Standard
  Draft standards are well understood and known to be quite stable. At least two interoperable implementations must exist, developed independently from separate code bases. The specification is believed to be mature and useful.
• Internet Standard
  Internet Standards have been fully accepted by the Internet community as highly mature and useful standards.

Experimental specifications:
A result of research or development efforts. They are not intended to be standards, but it is felt that the information they contain may be of use to the Internet community.

Informational specifications:
Simply provide general information for the Internet community.

Historic specifications:
RFCs that have been superceded by a more recent RFC and are considered obsolete.

Best Current Practice (BCP):
RFCs are documents that summarize the consensus of the Internet community's opinion on the best way to perform an operation or procedure. BCPs are guidelines, not standards.

Table below summarizes the RFCs that apply to the key Internet.

RFCs for Key Internet Standards