TCP/IP Standards

The standards for TCP/IP are published in a series of documents called Request for Comments (RFCs). RFCs describe the internal workings of the Internet. Some RFCs describe network services or protocols and their implementations, whereas others summarize policies. TCP/IP standards are always published as RFCs, although not all RFCs specify standards.

TCP/IP standards are not developed by a committee, but rather by consensus. Anyone can submit a document for publication as an RFC. Documents are reviewed by a technical expert, a task force, or the RFC editor, and then assigned a status. The status specifies whether a document is being considered as a standard.

There are five status assignments of RFCs as described in Table 1.1.

Table 1.1 Status Assignments of RFCs




Must be implemented on all TCP/IP-based hosts and gateways.


Encouraged that all TCP/IP-based hosts and gateways implement the RFC specifications. Recommended RFCs are usually implemented.


Implementation is optional. Its application has been agreed to but is not a requirement.

Limited Use

Not intended for general use.

Not recommended

Not recommended for implementation.

If a document is being considered as a standard, it goes through stages of development, testing, and acceptance known as the Internet Standards Process. These stages are formally labeled maturity levels. Table 1.2 lists the three maturity levels for Internet Standards.

Table 1.2 Maturity Levels for Internet Standards

Maturity Level


Proposed Standard

A Proposed Standard specification is generally stable, has resolved known design choices, is believed to be well understood, has received significant community review, and appears to enjoy enough community interest to be considered valuable.

Draft Standard

A Draft Standard must be well understood and known to be quite stable, both in its semantics and as a basis for developing an implementation.

Internet Standard

The Internet Standard specification (which might simply be referred to as a Standard) is characterized by a high degree of technical maturity and by a generally held belief that the specified protocol or service provides significant benefit to the Internet community.

When a document is published, it is assigned an RFC number. The original RFC is never updated. If changes are required, a new RFC is published with a new number. Therefore, it is important to verify that you have the most recent RFC on a particular topic.

RFCs can be obtained in several ways. To obtain any RFC or a full and current indexed listing of all RFCs published to date, see the Request For Comments link on the Web Resources page at .