Deprecating the "X-" Prefix and Similar Constructs in Application Protocols (RFC6648)
Original Publication Date: 2012-Jun-01
Included in the Prior Art Database: 2012-Jun-26
Internet Society Requests For Comment (RFCs)
P. Saint-Andre: AUTHOR [+2]
Many application protocols use parameters with textual (as opposed to numerical) names to identify data (media types, header fields in Internet mail messages and HTTP requests, vCard parameters and properties, etc.). Historically, designers and implementers of application protocols have often distinguished between standardized and unstandardized parameters by prefixing the names of unstandardized parameters with the string "X-" or similar constructs (e.g., "x."), where the "X" is commonly understood to stand for "eXperimental" or "eXtension".
Internet Engineering Task Force (IETF) P. Saint-Andre Request for Comments: 6648 Cisco Systems, Inc. BCP: 178 D. Crocker Category: Best Current Practice Brandenburg InternetWorking ISSN: 2070-1721 M. Nottingham Rackspace June 2012
Deprecating the "X-" Prefix and Similar Constructs in Application Protocols
Historically, designers and implementers of application protocols have often distinguished between standardized and unstandardized parameters by prefixing the names of unstandardized parameters with the string "X-" or similar constructs. In practice, that convention causes more problems than it solves. Therefore, this document deprecates the convention for newly defined parameters with textual (as opposed to numerical) names in application protocols.
Status of This Memo
This memo documents an Internet Best Current Practice.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on BCPs is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6648.
Saint-Andre, et al. Best Current Practice [Page 1]
RFC 6648 Deprecating "X-" June 2012
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