RFC 6648 - Deprecating the "X-" Prefix and Similar Constructs in Application Protocols

Status of This Memo: Best Current Practice
Published: June 2012
Authors: P. Saint-Andre (Cisco), D. Crocker (Brandenburg InternetWorking), M. Nottingham (Rackspace)

Abstract

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.

Contents

• 1. Introduction
• 2. Recommendations for Implementers of Application Protocols
• 3. Recommendations for Creators of New Parameters
• 4. Recommendations for Protocol Designers
• 5. Security Considerations
• 6. IANA Considerations
• 7. Acknowledgements
• Appendix A. Background
• Appendix B. Analysis
• References
• Authors' Addresses

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