XML and MIME Types

RFC 3023: XML Media Types

RFC 3023 specifies the media types text/xml and application/xml for use in exchanging network entities that are written in the Extensible Markup Language (XML). While it is not specific to SIP, it impacts SIP when XML payloads are involved. This RFC defines the usage of XML in Internet protocols and the standardization of XML media types, enabling XML-based documents to be identified and exchanged using standard web protocols, including SIP in cases where XML payloads need to be conveyed within SIP messages.
RFC 3023 ensures that XML documents can be properly understood and processed by the receiving party when used as a payload in SIP communications.

RFC 6839: Additional Media Type Structured Syntax Suffixes

RFC 6839 updates RFC 3023 by introducing additional structured syntax suffixes for media types, which are used to specify the nature of the XML data in a more granular way. This document expands the framework established in RFC 3023, allowing for more precise classification and processing of XML-based content in web and internet communications.

RFC 7303: XML Media Types

RFC 7303 obsoletes RFC 3023, providing a revised and updated specification for XML media types. This document refines the standards for representing XML and its associated formats in internet media types, addressing the evolution of XML standards and practices. It offers a more comprehensive and up-to-date framework for handling XML content, including considerations for character encoding, handling of XML fragments, and compatibility with existing standards.