Network Working Group A. Miller
Request for Comment: 4708 The University of Auckland
Category: Informational October 2006
CellML Media Type
Status of This Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright (C) The Internet Society (2006).
This document standardises a new media type -- application/cellml+xml
-- for use in exchanging mathematical models represented in a CellML
Umbrella 1.0 compliant markup language.
The CellML Umbrella format is a standardised markup meta-language for
the interchange of mathematical models. The CellML Umbrella format
provides a common base that is supported by a number of specific
formats used in the interchange of mathematical models. The CellML
Umbrella format provides enough information to determine which
specific language is used to express the model. The syntax and
semantics of the CellML Umbrella format are defined by
The CellML Umbrella format is an actual media format. Although
CellML Umbrella documents contain elements in namespaces defined by
other specifications such as [RDF] and [MATHML], the elements in
these namespaces do not contain sufficient information to define a
mathematical model, and so CellML provides the information required
to interconnect the different CellML components, as well as the
information required to link CellML components to their metadata. As
such, CellML Umbrella documents are more than just a collection of
entities defined elsewhere, and so a new media type is required to
As all well-formed CellML Umbrella documents are also well-formed XML
documents, the convention described in Section 7 of [RFC3023] has
been observed by use of the +xml suffix.
Miller Informational [Page 1]RFC 4708 CellML Media Type October 2006
The information in CellML Umbrella documents cannot be interpreted
without understanding the semantics of the XML elements used to mark
up the model structure. Therefore, the application top-level type is
used instead of the text top-level type.
2. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
The terms "element" and "document element" in this document are to be
interpreted as in [XML].
The term "XML namespace" is to be interpreted as in [NAMESPACES].
3. Media Type Registration for CellML Umbrella
MIME media type name: application
MIME subtype name: cellml+xml
Mandatory parameters: none
Optional parameters: charset
The charset parameter of application/cellml+xml is handled in the
same fashion as for application/xml, as specified in Section 3.2
of [RFC3023]. However, per conformance rule 4 of
[CELLML-UMBRELLA], valid CellML Umbrella documents MUST be in the
UTF-8 character set. If the charset parameter is present, it MUST
take the value "utf-8". CellML processing software SHOULD check
the charset field, and if it is present but not equal to "utf-8",
MAY attempt to recover from the error by processing the document
in the specified character set.
Encoding considerations: As per Section 3.2 of [RFC3023].
Security considerations: As per Section 5 of this document.
Interoperability considerations: As per Section 4.1 of this document.
CellML Umbrella Specification [CELLML-UMBRELLA].
Applications that use this media type: As per Section 4.2 of this
Miller Informational [Page 2]RFC 4708 CellML Media Type October 2006
Magic number(s): None.
XML processing software can identify CellML Umbrella documents
as XML documents that contain a document element with the local
The RECOMMENDED file extension for CellML Umbrella documents is
Some older software uses the file extension .xml. Software