Definitions for expressing standards requirements in IANA registries.
Scott Rose, Ólafur Guðmundsson · 2010
RFC 2119 defines words that are used in IETF standards documents to indicate standards compliance. These words are fine for defining new protocols, but there are certain deficiencies in using them when it comes to protocol maintainability. Protocols are maintained by either updating the core specifications or via changes in protocol registries. For example, protocols often use external algorithms to to provide security functionality such as cryptography. Cryptographic algorithms frequently have limited life cyles as new algorithms are phased in to replace older algorithms. This document proposes standard terms to use in protocol registries and possibly in standards track documents to indicate the life cycle support of protocol features and operations.