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Network Working Group                                      H. AlvestrandRequest for Comments: 1494                                  SINTEF DELAB                                                             S. Thompson                                                       Soft*Switch, Inc.                                                             August 1993Equivalences between 1988 X.400 andRFC-822 Message BodiesStatus of this Memo   This RFC specifies an IAB standards track protocol for the Internet   community, and requests discussion and suggestions for improvements.   Please refer to the current edition of the "IAB Official Protocol   Standards" for the standardization state and status of this protocol.   Distribution of this memo is unlimited.Table of Contents1.  Introduction .............................................22.  Equivalence Table Definition .............................23.  Generic conversions ......................................33.1.  Byte copy ..............................................33.2.  Text Conversion ........................................33.3.  Image Conversion .......................................33.4.  Tunneling ..............................................34.  Conversion Table for known X.400 and MIME  Types .........44.1.  MIME to X.400 Table ....................................44.2.  X.400 to MIME Table ....................................45.  Newly defined X.400 Body Parts ...........................55.1.  Use of OBJECT IDENTIFIERs and ASN.1 MACROS .............55.2.  The Generic MIME Extended Body Part ....................65.3.  The PostScript body part ...............................75.4.  The JPEG body part .....................................75.5.  The GIF body part ......................................86.  Newly defined MIME content-types .........................86.1.  The application/x400-bp content-type ...................86.2.  The image/g3fax content-type ...........................96.2.1.  G3Fax Parameters .....................................96.2.2.  Content Encoding .....................................106.3.  The Application/ODA content-type .......................117. Equivalence Definitions ...................................117.1. IA5Text - text/plain ....................................117.2. GeneralText - text/plain (ISO-8859) .....................127.3. BilaterallyDefined -  application/octet-stream ..........137.4. ODA - application/oda ...................................147.5. g3-facsimile - image/g3fax ..............................157.6. application/postscript -  postscript-body-part ..........167.7. application/jpeg - jpeg-body-part .......................16Alvestrand & Thompson                                           [Page 1]

RFC 1494              X.400/MIME Body Equivalences           August 19937.8. image/gif - gif-body-part ...............................168. OID Assignments ...........................................179. IANA Registration form for new mappings ...................1710. Security Considerations ..................................1811. Authors' Addresses .......................................1812. References ...............................................191.  Introduction   This document is a companion to [1], which defines the principles   behind interworking between MIME-basedRFC-822 mail and X.400 mail.   This document describes the content of the "IANA MHS/MIME Equivalence   table" referenced in the companion document, and defines the initial   configuration of this table.  Mappings for new MIME content-types   and/or X.400 body part types should be registered with the IANA to   minimize redundancy and promote interoperability.   In MIME, the term "content-type" is used to refer to an information   object contained in the body of a message.  In contrast, X.400 uses   the term "body part type."  In this document, the term "body part" is   used to refer to either.   Please send comments to the MIME-MHS mailing list:   <mime-mhs@surfnet.nl>.2.  Equivalence Table Definition   For each MIME content-type/X.400 body part pair, the Equivalence   Table will contain an entry with the following sections:   X.400 Body Part        This section identifies the X.400 Body Part governed by this        Table entry. It includes any OBJECT IDENTIFIERs or other        parameters necessary to uniquely identify the Body Part.   MIME Content-Type        This section identifies the MIME content-type governed by this        Table entry.  The MIME content-type named here must be        registered with the IANA.   Conversion Type        This section identifies the type of conversion applied.  See the        section on Generic Conversions for an explanation of the        possible values.Alvestrand & Thompson                                           [Page 2]

RFC 1494              X.400/MIME Body Equivalences           August 1993   Comments (optional)        This section gives any additional commentary that might be        useful in understanding the mapping between the X.400 and MIME        representations.   The initial Equivalence Table entries in this document are described   using this convention.  Any future submissions to the IANA should   follow this format.3.  Generic conversions3.1.  Byte copy   This is the trivial case, that is, no conversion at all.  The byte   stream is simply copied between MIME and X.400.   This is the preferred conversion, since it is the simplest.   Implementors and vendors will be registering OBJECT IDENTIFIERs and   MIME content-types for their various objects.  They are STRONGLY   ENCOURAGED to specify their content formats such that a gateway can   use Byte Copy to map between them.   Note that in some cases, it is necessary to define exactly which   ASN.1 construct to replace with the content of the MIME object.3.2.  Text Conversion   This type of conversion applies to text objects that cannot be mapped   using a simple Byte Copy.  Conversion involves scanning and   reformatting the object.  For example, the MIME and X.400 objects   might differ in their encoding of nonstandard characters, or line or   page breaks.3.3.  Image Conversion   This conversion type applies to raster images, like Group 3 Facsimile   or JPEG.  Again, it differs from Byte Copy in that it involves   scanning reformatting the byte stream.  It differs from Text   Conversion in that it is pixel- oriented, rather than character-   oriented.3.4.  Tunneling   This is not a conversion at all, but an encapsulation of the object.   This is the fallback conversion, used when no explicit mapping   applies.Alvestrand & Thompson                                           [Page 3]

RFC 1494              X.400/MIME Body Equivalences           August 19934.  Conversion Table for known X.400 and MIME Types   This section itemizes the equivalences for all currently known MIME   content-types and X.400 body parts.4.1.  MIME to X.400 Table       MIME content-type          X.400 Body Part             Section       -----------------          ------------------          -------       text/plain         charset=us-ascii         ia5-text                     7.1         charset=iso-8859-x       EBP - GeneralText            7.2       text/richtext              no mapping defined           5.2       application/oda            EBP - ODA                    7.4       application/octet-stream   bilaterally-defined          7.3       application/postscript     EBP - mime-postscript-body   5.4, 7.6       image/g3fax                g3-facsimile                 6.2, 7.5       image/jpeg                 EBP - mime-jpeg-body         5.5, 7.7       image/gif                  EBP - mime-gif-body          5.6, 7.8       audio/basic                no mapping defined           5.2       video/mpeg                 no mapping defined           5.2       Abbreviation: EBP - Extended Body Part4.2.  X.400 to MIME Table                                Basic Body Parts       X.400 Basic Body Part      MIME content-type           Section       ---------------------      --------------------        -------       ia5-text                   text/plain;charset=us-ascii 7.1       voice                      No Mapping Defined          6.1       g3-facsimile               image/g3fax                 6.2, 7.5       g4-class1                  no mapping defined          6.1       teletex                    no mapping defined          6.1       videotex                   no mapping defined          6.1       encrypted                  no mapping defined          6.1       bilaterally-defined        application/octet-stream    7.3       nationally-defined         no mapping defined          6.1       externally-defined         See Extended Body Parts     6.1       X.400 Extended Body Part  MIME content-type              Section       ------------------------- --------------------           -------       GeneralText               text/plain;charset=iso-8859-x  7.2       ODA                       application/oda                7.4       mime-postscript-body      application/postscript         5.3, 7.6       mime-jpeg-body            image/jpeg                     5.4, 7.7       mime-gif-body             image/gif                      5.5, 7.8Alvestrand & Thompson                                           [Page 4]

RFC 1494              X.400/MIME Body Equivalences           August 19935.  Newly defined X.400 Body Parts   This section defines new X.400 Body Parts for the purposes of   interworking with MIME.   All new X.400 Body Parts defined here will be Extended Body Parts, as   defined in CCITT Recommendation X.420 [2].5.1.  Use of OBJECT IDENTIFIERs and ASN.1 MACROS   X.420 dictates that Extended Body Parts shall:       (1)  use OBJECT IDENTIFIERs (OIDs) to uniquely identify            the contents, and       (2)  be defined by using the ASN.1 Macro:               EXTENDED-BODY-PART-TYPE MACRO::=               BEGIN                  TYPE NOTATION  ::= Parameters Data                  VALUE NOTATION ::= value (VALUE OBJECT IDENTIFIER)                  Parameters     ::=  "PARAMETERS" type "IDENTIFIED"                                      "BY" value(OBJECT IDENTIFIER)                                    | empty;                  Data           ::= "DATA" type               END   To meet these requirements, this document uses the OID      mime-mhs-bodies   defined in [1], as the root OID for X.400 Extended Body Parts defined   for MIME interworking.   Each Extended Body Part contains Data and optional Parameters, each   being named by an OID.  To this end, two OID subtrees are defined   under mime-mhs-bodies, one for Data, and the other for Parameters:          mime-mhs-bp-data  OBJECT IDENTIFIER ::=                          { mime-mhs-bodies 1 }          mime-mhs-bp-parameter OBJECT IDENTIFIER ::=                          { mime-mhs-bodies 2 }   All definitions of X.400 body parts submitted to the IANA for   registration must use the Extended Body Part Type macro for the   definition.  See the next section for an example.Alvestrand & Thompson                                           [Page 5]

RFC 1494              X.400/MIME Body Equivalences           August 1993   Lastly, the IANA will use the mime-mhs-bp-data and mime-mhs-bp-   parameter OIDs as root OIDs for any new MIME content-type/subtypes   that aren't otherwise registered in the Equivalence Table.5.2.  The Generic MIME Extended Body Part   The following X.400 Body Part is defined to carry any MIME content-   type for which there is no explicit IANA registered mapping.         mime-body-part EXTENDED-BODY-PART-TYPE            PARAMETERS MimeParameters               IDENTIFIED BY mime-generic-parameters            DATA            OCTET STRING            ::= mime-generic-data         MimeParameters ::=             SEQUENCE {                 content-type       IA5String,                 content-parameters SEQUENCE OF                                    SEQUENCE {                                        parameter          IA5String,                                        parameter-value    IA5String                                    }                                    -- fromRFC-1327, sec. 5.1.12                 other-header-fields RFC822FieldList             }         mime-generic-parameters OBJECT IDENTIFIER ::=             { mime-mhs-bp-parameter 1 }         mime-generic-data       OBJECT IDENTIFIER ::=             { mime-mhs-bp-data  1 }   To convert the MIME content-type into the X.400 mime- body-part:       (1)  Copy the "type/subtype" string from the MIME            Content-Type: header field into            MimeParameters.content-type       (2)  For each "parameter=value" string in the MIME            Content-Type header field, create a            MimeParameters.content-parameters structure, and copy            the "parameter" string into MimeParameters.content-            parameters.parameter field and the "value" string            into the paired MimeParameters.content-            parameters.parameter-value field.       (3)  Convert the MIME body part into its canonical form.Alvestrand & Thompson                                           [Page 6]

RFC 1494              X.400/MIME Body Equivalences           August 1993            (Seeappendix H of RFC 1341 [3] for a discussion            of canonical in this context.) Said another way,            reverse the transfer encoding to recover the original            byte stream.       (4)  Copy the canonical byte stream into the mime-body-            part.data octet string.       (5)  Remove the Content-type and the Content-transfer-            encoding header fields from the MIME body part'sRFC822 header.       (6)  Any header fields starting with "Content-" in the            MIME body part is placed in the optional other-            header-fields structure. Note that this can only            occur when the MIME content-type occurs as part of a            "multipart" content-type.   The mapping from the X.400 mime-body-part to a MIME content-type is   the inverse of the above steps.5.3.  The PostScript body part   The following Extended Body Part is defined for PostScript data   streams.  It has no parameters.         postscript-body-part EXTENDED-BODY-PART-TYPE           DATA             OCTET STRING           ::= mime-postscript-body         mime-postscript-body OBJECT IDENTIFIER ::=                   { mime-mhs-bp-data 2 }5.4.  The JPEG body part   The following Extended Body Part is defined for JPEG data streams.   It has no parameters.          jpeg-body-part EXTENDED-BODY-PART-TYPE            DATA            OCTET STRING            ::= mime-jpeg-body          mime-jpeg-body OBJECT IDENTIFIER ::=                  { mime-mhs-bp-data 3 }Alvestrand & Thompson                                           [Page 7]

RFC 1494              X.400/MIME Body Equivalences           August 19935.5.  The GIF body part   The following Extended Body Part is defined for GIF data streams.  It   has no parameters.          gif-body-part EXTENDED-BODY-PART-TYPE            DATA            OCTET STRING            ::= mime-gif-body          mime-gif-body OBJECT IDENTIFIER ::=                  { mime-mhs-bp-data 4 }6.  Newly defined MIME content-types   This section defines new MIME content-types for the purposes of   interworking with X.400.6.1.  The application/x400-bp content-type   This content-type is defined to carry any X.400(88) body part for   which there is no registered IANA mapping.       The content-type field is         application/x400-bp       The parameters are:             bp-type=<INTEGER or OBJECT IDENTIFIER>   The body contains the raw ASN.1 IPM.body octet stream, including the   initial tag octet.   If the body is a basic body part, the bp-type parameter is set to the   number of the body part's context-specific tag, that is, the tag of   the IPMS.Body.BodyPart component.   If the body is an Extended Body Part, the bp-type parameter is set to   the OBJECT IDENTIFIER from            IPMS.body.externally-defined.data.direct-reference   No attempt is made to turn the parameters of Extended Body Parts into   MIME parameters.  (This task is the responsibility of the recipient's   UA).   For example, a basic VideotexBodyPart will haveAlvestrand & Thompson                                           [Page 8]

RFC 1494              X.400/MIME Body Equivalences           August 1993      Content-type=application/x400-bp; bp-type=6   whilst a Extended Videotex body part will have      Content-type=application/x400-bp; bp-type=2.6.1.4.5   application/x400-bp will need a content-transfer-encoding of base64   or quoted-printable when carried in 7-bit MIME.  Since there is no   way to know beforehand the content, it is recommended to just inspect   the first 1 KByte or so of data and choose the one that seems to   produce the more compact encoding.   If this is not feasible, Base64 is recommended.6.2.  The image/g3fax content-type   This content-type is defined to carry G3 Facsimile byte streams.   In general, a G3Fax image contains 3 pieces of information:       (1)  A set of flags indicating the particular coding            scheme.  CCITT Recommendation T.30 defines how the            flags are transmitted over telephones. In this            medium, the flags are carried as parameters in the            MIME content-type header field.       (2)  A structure that divides the bits into pages.  CCITT            recommendation T.30 describes how to define page            boundaries.  A page break algorithm is defined here            that is independent of how the image data is            conveyed.       (3)  For each page, a sequence of bits that form the            encoding of the image.  CCITT recommendation T.4            defines the bit image format.  This is used without            change.6.2.1.  G3Fax Parameters   The following parameters are defined:       (1)  page-length - possible values: A4, B4 and Unlimited       (2)  page-width - possible values: A3, A4, B4       (3)  encoding - possible values: 1-dimensional, 2-            dimensional, UncompressedAlvestrand & Thompson                                           [Page 9]

RFC 1494              X.400/MIME Body Equivalences           August 1993       (4)  resolution - possible values: Fine, Coarse       (5)  DCS - a bit string, represented in Base64.       (6)  pages - an integer, giving the number of pages in the            document   If nothing is specified, the default parameter settings are:         page-length=A4         page-width=A4         encoding=1-dimensional         resolution=Coarse   It is possible (but misleading) to view the representation of these   values as single-bit flags. They correspond to the following bits of   the T.30 control string and X.400 G3FacsimileParameters:       Parameter               T.30 bit        X.400 bit       page-length=A4             no bit set       page-length=B4          19              21       page-length=Unlimited   20              20       page-width=A4              no bit set       page-width=A3           18              22       page-width=B4           17              23       encoding=1-dimensional     no bit set       encoding=2-dimensional  16              8       encoding=Uncompressed   26              30       resolution=Coarse          no bit set       resolution=Fine         15              9   The reason for the different bit numbers is that X.400 counts bits in   an octet from the MSB down to the LSB, while T.30 uses the opposite   numbering scheme.   If any bit but these are set in the Device Control String, the DCS   parameter should be supplied.6.2.2.  Content Encoding   X.400 defines the g3-facsimile data stream as a SEQUENCE of BIT   STRINGs. Each BIT STRING is a page of facsimile image data, encoded   as defined by Recommendation T.4.  The following content encoding is   reversible between MIME and X.400 and ensures that page breaks areAlvestrand & Thompson                                          [Page 10]

RFC 1494              X.400/MIME Body Equivalences           August 1993   honored in the MIME representation.   An EOL is defined as a bit sequence of          000000000001 (eleven zeroes and a one).   Each page of the message is delimited by a sequence of six (6) EOLs   that MUST start on a byte boundary.  The image bit stream is padded   as needed to achieve this alignment.   Searching for the boundary is a matter of searching for the byte   sequence (HEX) 00 10 01 00 10 01 00 10 01, which cannot occur inside   the image.   SeeSection 7.5 for the algorithm on conversion between this encoding   and the X.400 encoding.   The Base64 content-transfer-encoding is appropriate for carrying this   content-type.6.3.  The Application/ODA content-type   The "ODA" subtype of application is used to indicate that a body   contains information encoded according to the Office Document   Architecture [4] standards, using the ODIF representation format.   For application/oda, the Content- Type line should also specify an   attribute/value pair that indicates the document application profile   (DAP), using the key word "profile", and the document class, using   the keyword "class".   For the keyword "class", the values "formatted", "processable" and   "formatted-processable" are legal values.   Thus an appropriate header field  might look like this:       Content-Type:  application/oda; profile=Q112;       class=formatted   Consult the ODA standard [4] for further information.   The Base64 content-transfer-encoding is appropriate for carrying ODA.7.  Equivalence Definitions7.1.  IA5Text - text/plain   X.400 Body Part: IA5Text   MIME Content-type: text/plain; charset=US-ASCIIAlvestrand & Thompson                                          [Page 11]

RFC 1494              X.400/MIME Body Equivalences           August 1993   Conversion Type: Byte copy   Comments:   When mapping from X.400 to MIME, the "repertoire" parameter is   ignored.   When mapping from MIME to X.400, the "repertoire" parameter is set to   IA5 (5).   NOTE: The MIME Content-type headers are omitted, when mapping from   X.400 to MIME, if and only if the IA5Text body part is the only body   part in the IPMS.Body sequence.   NOTE: IA5Text specifies the "currency" symbol in position 2/4. This   is converted without comment to the "dollar" symbol, since the author   of this document has seen many documents in which the position was   intended to indicate "dollar" while he has not yet seen one in which   the "currency" symbol is intended.   (For reference: The T.50 (1988) recommendation, which defines IA5,   talks about ISO registered set number 2, while ASCII, using the   "dollar" symbol, is ISO registered set number 6. There are no other   differences.)7.2.  GeneralText - text/plain (ISO-8859)   X.400 Body Part: GeneralText; CharacterSets in                           6,100,101,109,110,126,127,138,144,148   MIME Content-Type: text/plain; charset=ISO-8859-(1-9)   Conversion Type: Byte copy   Comments:   When mapping from X.400 to MIME, the character-set chosen from table   below according to the value of Parameters.CharacterSets.   When mapping from MIME to X.400, GeneralText is an Extended Body   Part, hence it requires an OID.  The OID for the GeneralText body is   defined in [5], part 8, annex D, as {2 6 1 4 11}. The OID for the   parameters is {2 6 1 11 11}.   The Parameters.CharacterSets is set from table below according to the   value of "charset"   NOTE: The GeneralText body part is defined in ISO 10021-8 [5], and   NOT in the corresponding CCITT recommendation. Its parameters were   heavily modified in a defect report, and will be a SET OF INTEGER   (indicating the ISO registry numbers of all the used sets) in the   next version of the standard.Alvestrand & Thompson                                          [Page 12]

RFC 1494              X.400/MIME Body Equivalences           August 1993   The following table lists the MIME character sets and the   corresponding ISO registry numbers. If no correspondence is found,   this conversion fails, and the generic body part approach is used.   MIME charset    ISO IR numbers          Comment   -----------------------------------------------   ISO-8859-1      6, 100                  West European "8-bit ASCII"   ISO-8859-2      6, 101                  East European   ISO-8859-3      6, 109                  <regarded as obsolete>   ISO-8859-4      6, 110                  <regarded as obsolete>   ISO-8859-5      6, 144                  Cyrillic   ISO-8859-6      6, 127                  Arabic   ISO-8859-7      6, 126                  Greek   ISO-8859-8      6, 138                  Hebrew   ISO-8859-8      6, 148                  Other Latin-using languages   When converting from MIME to X.400, generate the correct OIDs for use   in the message envelope's Encoded Information Types by looking up the   ISO IR number in the above table, and then appending it to the id-   cs-eit-authority {1 0 10021 7 1 0} OID.   The escape sequences to designate and invoke the relevant character   sets in their proper positions must be added to the front of the   GeneralText character string.7.3.  BilaterallyDefined - application/octet-stream   X.400 Body Part: BilaterallyDefined   MIME Content-Type: Application/Octet-Stream (no parameters)   Conversion Type: Byte copy   Comments:   When mapping from MIME to X.400, if there are parameters present in   the Content-Type: header field, the conversion fails since the   BilaterallyDefined Body Part does not have any corresponding ASN.1   parameters.   DISCUSSION: The parameters "name" "type" and "conversions" are   advisory, but may in some cases give vital hints on the expected   handling of the file. The parameter "conversions" is not fully   defined, but it is expected that it will be useful, so we cannot drop   it and expect people to be satisfied.   The parameter "padding" changes the interpretation of the last byte   of the data, and so cannot be deleted.   An option is to prepend an IA5 body part that contains the parameter   text; this will aid unmodified readers, and can probably be madeAlvestrand & Thompson                                          [Page 13]

RFC 1494              X.400/MIME Body Equivalences           August 1993   reversible with suitable chicanery, but is it worth it????   Also, use of BilaterallyDefined Body Parts is specifically deprecated   in both 1988 and 1992 X.400.  It is retained solely for backward   compatibility with 1984 systems. 1992 X.400 defines a File Transfer   Body Part to solve this problem (i.e. binary file transfer through   email). The standard and its regional profiles are not solid enough   yet to exploit as a solution for this problem.7.4.  ODA - application/oda   X.400 Body Part: ODA   MIME Content-Type: application/oda   Conversion Type: Byte copy   Comments:   The ODA body part is defined in the CCITT document T.411 [6],appendix E, section E.2, "ODA identification in the P2 protocol of   MHS"   An abbreviated version of its ASN.1 definition is:       oda-body-part EXTENDED-BODY-PART-TYPE            PARAMETERS      OdaBodyPartParameters            DATA            OdaData            ::= id-et-oda       OdaBodyPartParameters ::= SET {            document-application-profile    [0] OBJECT IDENTIFIER            document-architecture-class     [1] INTEGER {                                            formatted (0)                                            processable (1)                                            formatted-processable(2)}}       id-et-oda OBJECT IDENTIFIER ::= { 2 8 1 0 1 }   Mapping from X.400 to MIME, the following is done:   The Parameters.document-application-profile is mapped onto the MIME   parameter "profile" according to the table below.       Profile         OBJECT IDENTIFIER       Q112            { iso (1) identified-organization (3) ewos (16)                         eg (2) oda (6) profile (0)  q112 (1) }   The Parameters.document-architecture-class is mapped onto the MIME   parameter "class" according to the table belowAlvestrand & Thompson                                          [Page 14]

RFC 1494              X.400/MIME Body Equivalences           August 1993       String                  Integer       formatted               formatted(0)       processable             processable(1)       formatted-processable   formatted-processable(2)   NOTE: This parameter is not defined inRFC 1341.   The body of the MIME content-type is the Data part of the ODA body   part.   When mapping from MIME to X.400, the following steps are done:   The Parameters.document-application-profile and Parameters.document-   architecture-class are set from the tables above.  If any of the   parameters are missing, the values for Q112 and formatted-processable   are used.   It is an option for the gateway implementor to try to access them   from inside the document, where they are defined as   document-profile.document-characteristics.document-architecture-class   document-profile.document-characteristics.document-application-profile   Gateways are NOT required to do this, since the document-   characteristics are optional parameters.  If a gateway does not, it   simply uses the defaulting rules defined above.   The OBJECT IDENTIFIERs for the document application profile and for   ODA {2 8 0 0} must be added to the Encoded Information Types   parameter of the message envelope.7.5.  g3-facsimile - image/g3fax   X.400 Body part: g3-facsimile   MIME Content-Type: image/g3fax   Conversion Type: nearly Byte copy   Comments:   The Parameters of the X.400 G3Fax body part are mapped to the   corresponding Parameters on the MIME Image/G3Fax body part and vice   versa.  Note that:       (1)  If fineResolution is not specified, pixels will be            twice as tall as they are wide       (2)  If any bit not corresponding to a specially namedAlvestrand & Thompson                                          [Page 15]

RFC 1494              X.400/MIME Body Equivalences           August 1993            option is set in the G3Fax NonBasicParameters, the            "DCS" parameter must be used.       (3)  Interworking is not guaranteed if any bit apart from            those specially named are used in the            NonBasicParameters   From X.400 to G3Fax, the body is created in the following way:       (1)  Any trailing EOL markers on each bitstring is            removed. The bistring is padded to a byte boundary.       (2)  6 consecutive EOL markers are appended to each            bitstring.       (3)  The padded bitstrings are concatenated together   An EOL marker is the bit sequence 000000000001 (11 zeroes and a one).   From G3Fax to X.400, the body is created in the following way:       (1)  The body is split into bitstrings at each occurrence            of 6 consecutive EOL markers, and trailing EOLs and            padding are removed       (2)  Each bitstring is made into an ASN.1 BITSTRING       (3)  The bitstrings are made into an ASN.1 SEQUENCE, which            forms the body of the G3Fax body part.7.6.  application/postscript - postscript-body-part   X.400 Body Part: Extended Body Part, OID postscript-body-part   MIME Content-Type: application/postscript   Conversion Type: Byte Copy7.7.  application/jpeg - jpeg-body-part   X.400 Body Part: Extended Body Part, OID jpeg-body-part   MIME Content-Type: application/jpeg   Conversion Type: Byte Copy7.8.  image/gif - gif-body-part   X.400 Body Part: Extended Body Part, OID gif-body-part   MIME Content-Type: application/gif   Conversion Type: Byte CopyAlvestrand & Thompson                                          [Page 16]

RFC 1494              X.400/MIME Body Equivalences           August 19938.  OID Assignments       MIME-MHS-MAPPINGS DEFINITIONS ::= BEGIN       IMPORTS          mail, mime-mhs, mime-mhs-bodies              FROM MIME-MHS;       mime-mhs-bp-data OBJECT IDENTIFIER ::=               { mime-mhs-bodies 1}       mime-mhs-bp-parameter OBJECT IDENTIFIER ::=               { mime-mhs-bodies 2}       mime-generic-data OBJECT IDENTIFIER ::=               { mime-mhs-bp-data 1}       mime-generic-parameters OBJECT IDENTIFIER ::=               { mime-mhs-bp-parameter 1}       mime-postscript-body OBJECT IDENTIFIER ::=               { mime-mhs-bp-data 2}       mime-jpeg-body OBJECT IDENTIFIER ::=               { mime-mhs-bp-data 3}       mime-gif-body OBJECT IDENTIFIER ::=               { mime-mhs-bp-data 4};9.  IANA Registration form for new mappings   To: IANA@isi.edu   Subject: Registration of new X.400/MIME content type mapping   MIME type name:   (this must have been registered previously with IANA)   X.400 body part:   X.400 Object Identifier for Data:   (If left empty, an OID will be assigned by IANA under   mime-mhs-bp-data)   X.400 Object Identifier for Parameters:Alvestrand & Thompson                                          [Page 17]

RFC 1494              X.400/MIME Body Equivalences           August 1993   (If left empty, an OID will be assigned by IANA under   mime-mhs-bp-parameter.  If it is not used, fill in the   words NOT USED.)   X.400 ASN.1 Syntax:   (must be an EXTENDED-BODY-PART-TYPE macro, or reference to   a Basic body part type)   Conversion algorithm:   (must be defined completely enough for independent   implementation. It may be defined by reference to RFCs).   Person & email address to contact for further information:   INFORMATION TO THE SUBMITTER:   The accepted registrations will be listed in the "Assigned   Numbers" series of RFCs.  The information in the   registration form is freely distributable.10.  Security Considerations   Security issues are not discussed in this memo.11.  Authors' Addresses   Harald Tveit Alvestrand   SINTEF DELAB   N-7034 Trondheim   NORWAY   EMail: Harald.Alvestrand@delab.sintef.no   Steven J. Thompson   Soft*Switch, Inc.   640 Lee Road   Wayne, PA 19087   Phone: (215) 640-7556   EMail: sjt@gateway.ssw.comAlvestrand & Thompson                                          [Page 18]

RFC 1494              X.400/MIME Body Equivalences           August 199312.  References   [1]  Alvestrand, H., Kille, S., Miles, R., Rose, M., and S. Thompson,        "Mapping between X.400 andRFC-822 Message Bodies",RFC 1495,        SINTEF DELAB, ISODE Consortium, Soft*Switch, Inc, Dover Beach        Consulting, Inc., Soft*Switch, Inc., August 1993.   [2]  CCITT Recommendation X.420 (1988), Interpersonal Messaging        System.   [3]  Borenstein, N, and N. Freed, "MIME: Mechanisms for Specifying        and Describing the Format of Internet Message Bodies",RFC 1341,        Bellcore, Innosoft, June 1992.   [4]  ISO 8613; Information Processing: Text and Office System; Office        Document Architecture (ODA) and Interchange Format (ODIF), Part        1-8, 1989.   [5]  ISO/IEC International Standard 10021, Information technology -        Text Communication - Message-Oriented Text Interchange Systems        (MOTIS) (Parts 1 to 8).   [6]  CCITT Recommendation T.411 (1988), Open Document Architecture        (ODA) and Interchange Format, Introduction and General        Principles.   [7]  Crocker, D., "Standard for the Format of ARPA Internet Text        Messages", STD 11,RFC 822, UDEL, August 1982.   [8]  Hardcastle-Kille, S., "Mapping between X.400(1988) / ISO 10021        andRFC-822",RFC 1327, University College London, May 1992.   [9]  CCITT Recommendation T.4, Standardization of Group 3 Facsimile        Apparatus for Document Transmission (1988).   [10] CCITT Recommendation T.30, Procedures For Document Facsimile        Transmission in the General Switched Telephone Network (1988).   [11] CCITT, Data Communication Networks - Message Handling Systems -        Recommendations X.400 - X.420 (1988 version).   [12] Alvestrand, H., "X.400 Use of Extended Character Sets",RFC1502, SINTEF DELAB, August 1993.Alvestrand & Thompson                                          [Page 19]

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