| IPP WG | M. Sweet |
| Internet-Draft | Apple Inc. |
| Obsoletes: 2910,3382 (if approved) | I. McDonald |
| Intended status: Standards Track | High North, Inc. |
| Expires: June 17, 2016 | December 15, 2015 |
Internet Printing Protocol/1.1: Encoding and Transport
draft-sweet-rfc2910bis-07
This document is one of a set of documents, which together describe all aspects of a new Internet Printing Protocol (IPP). IPP is an application level protocol that can be used for distributed printing using Internet tools and technologies. This document defines the rules for encoding IPP operations and IPP attributes into the Internet MIME media type called "application/ipp". This document also defines the rules for transporting a message body whose Content-Type is "application/ipp" over HTTP.
This draft is being submitted as an AD-sponsored replacement of RFCs 2910 and 3382, with drafts being reviewed and edited by the IEEE-ISTO's Printer Working Group IPP WG. The initial goal is to have an clean version of IPP/1.1 as an IETF Proposed Standard. The long-term goal is to advance IPP/1.1 to IETF Internet Standard.
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 17, 2016.
Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
This document contains the rules for encoding IPP operations and describes two layers: the transport layer and the operation layer.
The transport layer consists of an HTTP request and response. All IPP implementations MUST support HTTP/1.1, the relevant parts of which are described in the following RFCs:
IPP implementations MAY support HTTP/2 which is described in the following RFCs:
This document specifies the HTTP headers that an IPP implementation supports.
The operation layer consists of a message body in an HTTP request or response. The "Internet Printing Protocol/1.1: Model and Semantics" [RFC2911bis] and subsequent extensions (collectively known as the IPP Model) define the semantics of such a message body and the supported values. This document specifies the encoding of an IPP request and response message.
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].
Client: Initiator of outgoing IPP session requests and sender of outgoing IPP operation requests (Hypertext Transfer Protocol -- HTTP/1.1 [RFC7230] User Agent).
Document: An object created and managed by a Printer that contains description, processing, and status information. A Document object may have attached data and is bound to a single Job.
'ipp' URI: An IPP URI as defined in [RFC3510].
'ipps' URI: An IPPS URI as defined in [RFC7472].
Job: An object created and managed by a Printer that contains description, processing, and status information. The Job also contains zero or more Document objects.
Logical Device: A print server, software service, or gateway that processes Jobs and either forwards or stores the processed Job or uses one or more Physical Devices to render output.
Model: The semantics of operations, attributes, values, and status codes used in the Internet Printing Protocol as defined in the Internet Printing Protocol/1.1: Model and Semantics [RFC2911bis] and subsequent extensions.
Output Device: A single Logical or Physical Device.
Physical Device: A hardware implementation of an endpoint device, e.g., a marking engine, a fax modem, etc.
Printer: Listener for incoming IPP session requests and receiver of incoming IPP operation requests (Hypertext Transfer Protocol -- HTTP/1.1 [RFC7230] Server) that represents one or more Physical Devices or a Logical Device.
ABNF: Augmented Backus-Naur Form [RFC5234]
ASCII: American Standard Code for Information Interchange [ASCII]
HTTP: HyperText Transfer Protocol [RFC7230]
HTTPS: HTTP over TLS [RFC2818]
IANA: Internet Assigned Numbers Authority
IEEE: Institute of Electrical and Electronics Engineers
IESG: Internet Engineering Steering Group
IPP: Internet Printing Protocol (this document and [PWG5100.12])
ISTO: IEEE Industry Standards and Technology Organization
LPD: Line Printer Daemon Protocol [RFC1179]
PWG: IEEE-ISTO Printer Working Group <http://www.pwg.org/>
RFC: Request for Comments
TCP: Transmission Control Protocol [RFC793]
TLS: Transport Layer Security [RFC5246]
URI: Uniform Resource Identifier [RFC3986]
URL: Uniform Resource Locator [RFC3986]
UTF-8: Unicode Transformation Format - 8-bit [RFC3629]
The operation layer is the message body part of the HTTP request or response and it MUST contain a single IPP operation request or IPP operation response. Each request or response consists of a sequence of values and attribute groups. Attribute groups consist of a sequence of attributes each of which is a name and value. Names and values are ultimately sequences of octets.
The encoding consists of octets as the most primitive type. There are several types built from octets, but three important types are integers, character strings and octet strings, on which most other data types are built. Every character string in this encoding MUST be a sequence of characters where the characters are associated with some charset and some natural language. A character string MUST be in "reading order" with the first character in the value (according to reading order) being the first character in the encoding. A character string whose associated charset is US-ASCII whose associated natural language is US English is henceforth called a US-ASCII-STRING. A character string whose associated charset and natural language are specified in a request or response as described in the Model is henceforth called a LOCALIZED-STRING. An octet string MUST be in "Model order" with the first octet in the value (according to the Model order) being the first octet in the encoding. Every integer in this encoding MUST be encoded as a signed integer using two's-complement binary encoding with big-endian format (also known as "network order" and "most significant byte first"). The number of octets for an integer MUST be 1, 2 or 4, depending on usage in the protocol. Such one-octet integers, henceforth called SIGNED-BYTE, are used for the version-number and tag fields. Such two-byte integers, henceforth called SIGNED-SHORT are used for the operation-id, status-code and length fields. Four byte integers, henceforth called SIGNED-INTEGER, are used for value fields and the request-id.
The following two sections present the encoding of the operation layer in two ways:
An operation request or response MUST use the encoding described in these two sections.
An operation request or response is encoded as follows:
----------------------------------------------- | version-number | 2 bytes - required ----------------------------------------------- | operation-id (request) | | or | 2 bytes - required | status-code (response) | ----------------------------------------------- | request-id | 4 bytes - required ----------------------------------------------- | attribute-group | n bytes - 0 or more ----------------------------------------------- | end-of-attributes-tag | 1 byte - required ----------------------------------------------- | data | q bytes - optional -----------------------------------------------
Figure 1: IPP Message Format
The first three fields in the above diagram contain the value of attributes described in Section 3.1.1 of the Model.
The fourth field is the "attribute-group" field, and it occurs 0 or more times. Each "attribute-group" field represents a single group of attributes, such as an Operation Attributes group or a Job Attributes group (see the Model). The Model specifies the required attribute groups and their order for each operation request and response.
The "end-of-attributes-tag" field is always present, even when the "data" is not present. The Model specifies whether the "data" field is present for each operation request and response.
Each "attribute-group" field is encoded as follows:
----------------------------------------------- | begin-attribute-group-tag | 1 byte ---------------------------------------------------------- | attribute | p bytes |- 0 or more ----------------------------------------------------------
Figure 2: Attribute Group Encoding
An "attribute-group" field contains zero or more "attribute" fields.
Note, the values of the "begin-attribute-group-tag" field and the "end-of-attributes-tag" field are called "delimiter-tags".
An "attribute" field is encoded as follows:
----------------------------------------------- | attribute-with-one-value | q bytes ---------------------------------------------------------- | additional-value | r bytes |- 0 or more ----------------------------------------------------------
Figure 3: Attribute Encoding
When an attribute is single valued (e.g. "copies" with value of 10) or multi-valued with one value (e.g. "sides-supported" with just the value 'one-sided') it is encoded with just an "attribute-with-one-value" field. When an attribute is multi-valued with n values (e.g. "sides-supported" with the values 'one-sided' and 'two-sided-long-edge'), it is encoded with an "attribute-with-one-value" field followed by n-1 "additional-value" fields.
Each "attribute-with-one-value" field is encoded as follows:
----------------------------------------------- | value-tag | 1 byte ----------------------------------------------- | name-length (value is u) | 2 bytes ----------------------------------------------- | name | u bytes ----------------------------------------------- | value-length (value is v) | 2 bytes ----------------------------------------------- | value | v bytes -----------------------------------------------
Figure 4: Single Value Attribute Encoding
An "attribute-with-one-value" field is encoded with five subfields:
Each "additional-value" field is encoded as follows:
----------------------------------------------- | value-tag | 1 byte ----------------------------------------------- | name-length (value is 0x0000) | 2 bytes ----------------------------------------------- | value-length (value is w) | 2 bytes ----------------------------------------------- | value | w bytes -----------------------------------------------
Figure 5: Additional Attribute Value Encoding
An "additional-value" is encoded with four subfields:
Collection attributes create a named group containing related "member" attributes. The "attribute-with-one-value" field for a collection attribute is encoded as follows:
----------------------------------------------- | value-tag (value is 0x34) | 1 byte ----------------------------------------------- | name-length (value is u) | 2 bytes ----------------------------------------------- | name | u bytes ----------------------------------------------- | value-length (value is 0x0000) | 2 bytes ----------------------------------------------------------- | member-attribute | q bytes |-0 or more ----------------------------------------------------------- | end-value-tag (value is 0x37) | 1 byte ----------------------------------------------- | end-name-length (value is 0x0000) | 2 bytes ----------------------------------------------- | end-value-length (value is 0x0000) | 2 bytes -----------------------------------------------
Figure 6: Collection Attribute Encoding
Collection attribute is encoded with eight subfields:
Each "member-attribute" field is encoded as follows:
----------------------------------------------- | value-tag (value is 0x4A) | 1 byte ----------------------------------------------- | name-length (value is 0x0000) | 2 bytes ----------------------------------------------- | value-length (value is w) | 2 bytes ----------------------------------------------- | value (member-name) | w bytes ----------------------------------------------- | member-value-tag | 1 byte ----------------------------------------------- | name-length (value is 0x0000) | 2 bytes ----------------------------------------------- | member-value-length (value is x) | 2 bytes ----------------------------------------------- | member-value | x bytes -----------------------------------------------
Figure 7: Member Attribute Encoding
A "member-attribute" is encoded with eight subfields:
From the standpoint of a parser that performs an action based on a "tag" value, the encoding consists of:
----------------------------------------------- | version-number | 2 bytes - required ----------------------------------------------- | operation-id (request) | | or | 2 bytes - required | status-code (response) | ----------------------------------------------- | request-id | 4 bytes - required ----------------------------------------------------------- | tag (delimiter-tag or value-tag) | 1 byte | ----------------------------------------------- |-0 or more | empty or rest of attribute | x bytes | ----------------------------------------------------------- | end-of-attributes-tag | 1 byte - required ----------------------------------------------- | data | y bytes - optional -----------------------------------------------
Figure 8: Encoding Based On Value Tags
The following show what fields the parser would expect after each type of "tag":
The ABNF [RFC5234] syntax for an IPP message is shown in Figure 9.
ipp-message = ipp-request / ipp-response
ipp-request = version-number operation-id request-id
*attribute-group end-of-attributes-tag data
ipp-response = version-number status-code request-id
*attribute-group end-of-attributes-tag data
version-number = major-version-number minor-version-number
major-version-number = SIGNED-BYTE
minor-version-number = SIGNED-BYTE
operation-id = SIGNED-SHORT ; mapping from model
status-code = SIGNED-SHORT ; mapping from model
request-id = SIGNED-INTEGER ; whose value is > 0
attribute-group = begin-attribute-group-tag *attribute
attribute = attribute-with-one-value *additional-value
attribute-with-one-value = value-tag name-length name
value-length value
additional-value = value-tag zero-name-length
value-length value
name-length = SIGNED-SHORT ; number of octets of 'name'
name = LALPHA *( LALPHA / DIGIT / "-" / "_" / "." )
value-length = SIGNED-SHORT ; number of octets of 'value'
value = OCTET-STRING
data = OCTET-STRING
zero-name-length = %x00.00 ; name-length of 0
value-tag = %x10-FF ; see section 3.5.2
begin-attribute-group-tag = %x00-02 / %04-0F ; see section 3.5.1
end-of-attributes-tag = %x03 ; tag of 3
; see section 3.5.1
SIGNED-BYTE = BYTE
SIGNED-SHORT = 2BYTE
SIGNED-INTEGER = 4BYTE
DIGIT = %x30-39 ; "0" to "9"
LALPHA = %x61-7A ; "a" to "z"
BYTE = %x00-FF
OCTET-STRING = *BYTE
Figure 9: ABNF of IPP Message Format
Figure 10 defines additional terms that are referenced in this document and provides an alternate grouping of the delimiter tags.
delimiter-tag = begin-attribute-group-tag / ; see section 3.5.1
end-of-attributes-tag
delimiter-tag = %x00-0F ; see section 3.5.1
begin-attribute-group-tag = %x00 / operation-attributes-tag /
job-attributes-tag / printer-attributes-tag /
unsupported-attributes-tag / %x06-0F
operation-attributes-tag = %x01 ; tag of 1
job-attributes-tag = %x02 ; tag of 2
printer-attributes-tag = %x04 ; tag of 4
unsupported-attributes-tag = %x05 ; tag of 5
Figure 10: ABNF for Attribute Group Tags
Each "attribute-group" field MUST be encoded with the "begin-attribute-group-tag" field followed by zero or more "attribute" sub-fields.
Table 1 maps the Model group name to value of the "begin-attribute-group-tag" field:
| Model Document Group | "begin-attribute-group-tag" field values |
|---|---|
| Operation Attributes | "operations-attributes-tag" |
| Job Template Attributes | "job-attributes-tag" |
| Job Object Attributes | "job-attributes-tag" |
| Unsupported Attributes | "unsupported-attributes-tag" |
| Requested Attributes | (Get-Job-Attributes) "job-attributes-tag" |
| Requested Attributes | (Get-Printer-Attributes)"printer-attributes-tag" |
| Document Content | in a special position as described above |
For each operation request and response, the Model prescribes the required and optional attribute groups, along with their order. Within each attribute group, the Model prescribes the required and optional attributes, along with their order.
When the Model requires an attribute group in a request or response and the attribute group contains zero attributes, a request or response SHOULD encode the attribute group with the "begin-attribute-group-tag" field followed by zero "attribute" fields. For example, if the Client requests a single unsupported attribute with the Get-Printer-Attributes operation, the Printer MUST return no "attribute" fields, and it SHOULD return a "begin-attribute-group-tag" field for the Printer Attributes Group. The Unsupported Attributes group is not such an example. According to the Model, the Unsupported Attributes Group SHOULD be present only if the unsupported attributes group contains at least one attribute.
A receiver of a request MUST be able to process the following as equivalent empty attribute groups:
When the Model requires a sequence of an unknown number of attribute groups, each of the same type, the encoding MUST contain one "begin-attribute-group-tag" field for each attribute group even when an "attribute-group" field contains zero "attribute" sub-fields. For example, the Get-Jobs operation may return zero attributes for some jobs and not others. The "begin-attribute-group-tag" field followed by zero "attribute" fields tells the recipient that there is a Job in queue for which no information is available except that it is in the queue.
Some operation elements are called parameters in the Model. They MUST be encoded in a special position and they MUST NOT appear as operation attributes. These parameters are described in the subsections below.
The "version-number" field consists of a major and minor version-number, each of which is represented by a SIGNED-BYTE. The major version-number is the first byte of the encoding and the minor version-number is the second byte of the encoding. The protocol described in [RFC2911bis] has a major version-number of 1 (0x01) and a minor version-number of 1 (0x01). The ABNF for these two bytes is %x01.01.
Note: See Section 9 for more information on the "version-number" field and IPP version numbers.
The "operation-id" field contains an operation-id value as defined in the Model. The value is encoded as a SIGNED-SHORT and is located in the third and fourth bytes of the encoding of an operation request.
The "status-code" field contains a status-code value as defined in the Model. The value is encoded as a SIGNED-SHORT and is located in the third and fourth bytes of the encoding of an operation response.
If an IPP status-code is returned, then the HTTP status-code MUST be 200 (OK). With any other HTTP status-code value, the HTTP response MUST NOT contain an IPP message body, and thus no IPP status-code is returned.
The "request-id" field contains the request-id value as defined in the Model. The value is encoded as a SIGNED-INTEGER and is located in the fifth through eighth bytes of the encoding.
There are two kinds of tags:
Tags are part of the IANA IPP registry [IANA-IPP]
Table 2 specifies the values for the delimiter tags defined in this document:
| Tag Value (Hex) | Meaning |
|---|---|
| 0x00 | reserved for definition in a future standards track document |
| 0x01 | "operation-attributes-tag" |
| 0x02 | "job-attributes-tag" |
| 0x03 | "end-of-attributes-tag" |
| 0x04 | "printer-attributes-tag" |
| 0x05 | "unsupported-attributes-tag" |
| 0x06-0x0f | reserved for future delimiters in standards track documents |
When a "begin-attribute-group-tag" field occurs in the protocol, it means that zero or more following attributes up to the next delimiter tag are attributes belonging to the attribute group specified by the value of the "begin-attribute-group-tag". For example, if the value of "begin-attribute-group-tag" is 0x01, the following attributes are members of the Operations Attributes group.
The "end-of-attributes-tag" (value 0x03) MUST occur exactly once in an operation and MUST be the last "delimiter-tag". If the operation has a document-data group, the Document data in that group follows the "end-of-attributes-tag".
The order and presence of "attribute-group" fields (whose beginning is marked by the "begin-attribute-group-tag" subfield) for each operation request and each operation response MUST be that defined in the Model.
A Printer MUST treat a "delimiter-tag" (values from 0x00 through 0x0F) differently from a "value-tag" (values from 0x10 through 0xFF) so that the Printer knows there is an entire attribute group as opposed to a single value.
The remaining tables show values for the "value-tag" field, which is the first octet of an attribute. The "value-tag" field specifies the type of the value of the attribute.
Table 3 specifies the "out-of-band" values for the "value-tag" field defined in this document:
| Tag Value (Hex) | Meaning |
|---|---|
| 0x10 | unsupported |
| 0x11 | reserved for 'default' for definition in a future standards track document |
| 0x12 | unknown |
| 0x13 | no-value |
| 0x14-0x1F | reserved for "out-of-band" values in future standards track documents. |
Table 4 specifies the integer values for the "value-tag" field:
| Tag Value (Hex) | Meaning |
|---|---|
| 0x20 | reserved for definition in a future standards track document |
| 0x21 | integer |
| 0x22 | boolean |
| 0x23 | enum |
| 0x24-0x2F | reserved for integer types for definition in future standards track documents |
Table 5 specifies the octetString values for the "value-tag" field defined in this document:
| Tag Value (Hex) | Meaning |
|---|---|
| 0x30 | octetString with an unspecified format |
| 0x31 | dateTime |
| 0x32 | resolution |
| 0x33 | rangeOfInteger |
| 0x34 | begCollection |
| 0x35 | textWithLanguage |
| 0x36 | nameWithLanguage |
| 0x37 | endCollection |
| 0x38-0x3F | reserved for octetString type definitions in future standards track documents |
Table 6 specifies the character-string values for the "value-tag" field defined in this document:
| Tag Value (Hex) | Meaning |
|---|---|
| 0x40 | reserved for definition in a future standards track document |
| 0x41 | textWithoutLanguage |
| 0x42 | nameWithoutLanguage |
| 0x43 | reserved for definition in a future standards track document |
| 0x44 | keyword |
| 0x45 | uri |
| 0x46 | uriScheme |
| 0x47 | charset |
| 0x48 | naturalLanguage |
| 0x49 | mimeMediaType |
| 0x4A | memberAttrName |
| 0x4B-0x5F | reserved for character string type definitions in future standards track documents |
Note: An attribute value always has a type, which is explicitly specified by its tag; one such tag value is "nameWithoutLanguage". An attribute's name has an implicit type, which is keyword.
The values 0x60-0xFF are reserved for future type definitions in standards track documents.
The tag 0x7F is reserved for extending types beyond the 255 values available with a single byte. A tag value of 0x7F MUST signify that the first 4 bytes of the value field are interpreted as the tag value. Note this future extension doesn't affect parsers that are unaware of this special tag. The tag is like any other unknown tag, and the value length specifies the length of a value, which contains a value that the parser treats atomically. Values from 0x00000000 to 0x3FFFFFFF are reserved for definition in future standards track documents. The values 0x40000000 to 0x7FFFFFFF are reserved for vendor extensions.
The "name-length" field consists of a SIGNED-SHORT and specifies the number of octets in the immediately following "name" field. The value of this field excludes the two bytes of the "name-length" field. For example, if the "name" field contains 'sides', the value of this field is 5.
If a "name-length" field has a value of zero, the following "name" field is empty and the following value is treated as an additional value for the attribute encoded in the nearest preceding "attribute-with-one-value" field. Within an attribute group, if two or more attributes have the same name, the attribute group is malformed (see [RFC2911bis]). The zero-length name is the only mechanism for multi-valued attributes.
The "name" field contains the name of an attribute. The Model specifies such names.
The "value-length" field consists of a SIGNED-SHORT which specifies the number of octets in the immediately following "value" field. The value of this field excludes the two bytes of the "value-length" field. For example, if the "value" field contains the keyword (string) value 'one-sided', the value of this field is 9.
For any of the types represented by binary signed integers, the sender MUST encode the value in exactly four octets.
For any of the types represented by binary signed bytes, the sender MUST encode the value in exactly one octet.
For any of the types represented by character-strings, the sender MUST encode the value with all the characters of the string and without any padding characters.
For "out-of-band" "value-tag" fields defined in this document, such as 'unsupported', the "value-length" MUST be 0 and the "value" empty; the "value" has no meaning when the "value-tag" has one of these "out-of-band" values. For future "out-of-band" "value-tag" fields, the same rule holds unless the definition explicitly states that the "value-length" MAY be non-zero and the "value" non-empty
The syntax types (specified by the "value-tag" field) and most of the details of the representation of attribute values are defined in the Model. Table 7 augments the information in the Model and defines the syntax types from the Model in terms of the 5 basic types defined in Section 3. The 5 types are US-ASCII-STRING, LOCALIZED-STRING, SIGNED-INTEGER, SIGNED-SHORT, SIGNED-BYTE, and OCTET-STRING.
| Syntax of Attribute Value | Encoding |
|---|---|
| textWithoutLanguage, nameWithoutLanguage | LOCALIZED-STRING |
| textWithLanguage | OCTET-STRING consisting of 4 fields: a SIGNED-SHORT which is the number of octets in the following field, a value of type natural-language, a SIGNED-SHORT which is the number of octets in the following field, and a value of type textWithoutLanguage. The length of a textWithLanguage value MUST be 4 + the value of field a + the value of field c. |
| nameWithLanguage | OCTET-STRING consisting of 4 fields: a SIGNED-SHORT which is the number of octets in the following field, a value of type natural-language, a SIGNED-SHORT which is the number of octets in the following field, and a value of type nameWithoutLanguage. The length of a nameWithLanguage value MUST be 4 + the value of field a + the value of field c. |
| charset, naturalLanguage, mimeMediaType, keyword, uri, and uriScheme | US-ASCII-STRING |
| boolean | SIGNED-BYTE where 0x00 is 'false' and 0x01 is 'true' |
| integer and enum | a SIGNED-INTEGER |
| dateTime | OCTET-STRING consisting of eleven octets whose contents are defined by "DateAndTime" in RFC 1903 [RFC1903] |
| resolution | OCTET-STRING consisting of nine octets of 2 SIGNED-INTEGERs followed by a SIGNED-BYTE. The first SIGNED-INTEGER contains the value of cross feed direction resolution. The second SIGNED-INTEGER contains the value of feed direction resolution. The SIGNED-BYTE contains the units value. |
| rangeOfInteger | Eight octets consisting of 2 SIGNED-INTEGERs. The first SIGNED-INTEGER contains the lower bound and the second SIGNED-INTEGER contains the upper bound. |
| 1setOf X | Encoding according to the rules for an attribute with more than 1 value. Each value X is encoded according to the rules for encoding its type. |
| octetString | OCTET-STRING |
| collection | Encoding as defined in Section 3.1.6. |
The attribute syntax type of the value determines its encoding and the value of its "value-tag".
The "data" field MUST include any data required by the operation.
HTTP/1.1 [RFC7230] is the REQUIRED transport layer for this protocol. HTTP/2 [RFC7540] is an OPTIONAL transport layer for this protocol.
The operation layer has been designed with the assumption that the transport layer contains the following information:
It is REQUIRED that a Printer implementation support HTTP over the IANA assigned Well Known Port 631 (the IPP default port), though a Printer implementation may support HTTP over some other port as well.
Each HTTP operation MUST use the POST method where the request-URI is the object target of the operation, and where the "Content-Type" of the message body in each request and response MUST be "application/ipp". The message body MUST contain the operation layer and MUST have the syntax described in Section 3.2 "Syntax of Encoding". A Client implementation MUST adhere to the rules for a Client described for HTTP [RFC7230]. A Printer (server) implementation MUST adhere the rules for an origin server described for HTTP [RFC7230].
An IPP server sends a response for each request that it receives. If an IPP server detects an error, it MAY send a response before it has read the entire request. If the HTTP layer of the IPP server completes processing the HTTP headers successfully, it MAY send an intermediate response, such as "100 Continue", with no IPP data before sending the IPP response. A Client MUST expect such a variety of responses from an IPP server. For further information on HTTP, consult the HTTP documents [RFC7230].
An HTTP/1.1 server MUST support chunking for IPP requests, and an IPP Client MUST support chunking for IPP responses according to HTTP/1.1 [RFC7230].
All Printer and Job objects are identified by a Uniform Resource Identifier (URI) [RFC3986] so that they can be persistently and unambiguously referenced. Jobs can also be identified by a combination of Printer URI and Job ID.
Some operation elements are encoded twice, once as the request-URI on the HTTP Request-Line and a second time as a REQUIRED operation attribute in the application/ipp entity. These attributes are the target for the operation and are called "printer-uri" and "job-uri".
Note: The target URI is included twice in an operation referencing the same IPP object, but the two URIs can be different. For example, the HTTP request URI can be relative while the IPP request URI MUST be absolute.
HTTP allows Clients to generate and send a relative URI rather than an absolute URI. A relative URI identifies a resource with the scope of the HTTP server, but does not include scheme, host or port. The following statements characterize how URIs are used in the mapping of IPP onto HTTP:
The IPP URI schemes are 'ipp' [RFC3510] and 'ipps' [RFC7472]. Clients and Printers MUST support the ipp-URI value in the following IPP attributes:
Each of the above attributes identifies a Printer or Job. The ipp-URI is intended as the value of the attributes in this list. All of these attributes have a syntax type of 'uri', but there are attributes with a syntax type of 'uri' that do not use the 'ipp' scheme, e.g. "job-more-info".
If a Printer registers its URI with a directory service, the Printer MUST register an ipp-URI.
When a Client sends a request, it MUST convert a target ipp-URI to a target http-URL (or ipps-URI to a target https-URI) for the HTTP layer according to the following rules:
The Client MUST use the target http-URL or https-URL in both the HTTP Request-Line and HTTP headers, as specified by HTTP [RFC7230]. However, the Client MUST use the target ipp-URI or ipps-URI for the value of the "printer-uri" or "job-uri" operation attribute within the application/ipp body of the request. The server MUST use the ipp-URI or ipps-URI for the value of the "printer-uri", "job-uri" or "printer-uri-supported" attributes within the application/ipp body of the response.
For example, when an IPP Client sends a request directly, i.e., no proxy, to an ipp-URI "ipp://printer.example.com/ipp/print/myqueue", it opens a TCP connection to port 631 (the IPP implicit port) on the host "printer.example.com" and sends the following data:
POST /ipp/print/myqueue HTTP/1.1
Host: printer.example.com:631
Content-type: application/ipp
Transfer-Encoding: chunked
...
"printer-uri" 'ipp://printer.example.com/ipp/print/myqueue'
(encoded in application/ipp message body)
...
Figure 11: Direct IPP Request
As another example, when an IPP Client sends the same request as above via a proxy "myproxy.example.com", it opens a TCP connection to the proxy port 8080 on the proxy host "myproxy.example.com" and sends the following data:
POST http://printer.example.com:631/ipp/print/myqueue HTTP/1.1
Host: printer.example.com:631
Content-type: application/ipp
Transfer-Encoding: chunked
...
"printer-uri" 'ipp://printer.example.com/ipp/print/myqueue'
(encoded in application/ipp message body)
...
Figure 12: Proxied IPP Request
The proxy then connects to the IPP origin server with headers that are the same as the "no-proxy" example above.
See the section on "IANA Considerations" in the document "Internet Printing Protocol/1.1: Model and Semantics" [RFC2911bis] for information on IANA considerations. This document adds no additional considerations.
See the section on "Internationalization Considerations" in the document "Internet Printing Protocol/1.1: Model and Semantics" [RFC2911bis] for information on internationalization. This document adds no additional issues.
The IPP Model and Semantics document [RFC2911bis] discusses high level security requirements (Client Authentication, Server Authentication and Operation Privacy). Client Authentication is the mechanism by which the Client proves its identity to the server in a secure manner. Server Authentication is the mechanism by which the server proves its identity to the Client in a secure manner. Operation Privacy is defined as a mechanism for protecting operations from eavesdropping.
This section defines the security requirements for IPP Clients and IPP objects.
IPP Clients and Printers SHOULD support Digest Authentication [RFC7616]. If supported, MD5 and MD5-sess MUST be implemented and supported. Use of the Message Integrity feature (qop="auth-int") is OPTIONAL.
The reasons that IPP Clients and Printers SHOULD (rather than MUST) support Digest Authentication are:
IPP Clients and Printers SHOULD support Transport Layer Security (TLS) [RFC5246] [RFC7525] for Server Authentication and Operation Privacy. IPP Printers MAY also support TLS for Client Authentication. IPP Clients and Printers MAY support Basic Authentication [RFC7617] for User Authentication if the channel is secure.
The IPP Model and Semantics document [RFC2911bis] defines two Printer attributes ("uri-authentication-supported" and "uri-security-supported") that the Client can use to discover the security policy of a Printer. That document also outlines IPP-specific security considerations and is the primary reference for security implications with regard to the IPP protocol itself.
IPP uses the "Upgrading to TLS Within HTTP/1.1" mechanism [RFC2817] for 'ipp' URIs. The Client requests a secure TLS connection by using the HTTP "Upgrade" header, while the server agrees in the HTTP response. The switch to TLS occurs either because the server grants the Client's request to upgrade to TLS, or a server asks to switch to TLS in its response. Secure communication begins with a server's response to switch to TLS.
IPP uses the "HTTPS: HTTP over TLS" mechanism [RFC2818] for 'ipps' URIs. The Client and server negotiate a secure TLS connection immediately and unconditionally.
It is beyond the scope of this specification to mandate conformance with versions of IPP other than 1.1. IPP was deliberately designed, however, to make supporting other versions easy. IPP Printer implementations SHOULD:
IPP Clients SHOULD:
The following are rules regarding the "version-number" parameter (see Section 3.3):
The following are rules regarding security, the "version-number" parameter, and the URI scheme supplied in target attributes and responses:
The following changes have been made since the publication of RFC 2910:
| [IANA-CON] | Narten, T. and H. Alvestrand, Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. |
| [IANA-IPP] | IANA IPP Registry" | , "
| [PWG5100.3] | Ocke, K. and T. Hastings, "IPP Production Printing Attributes Set 1", February 2001. |
| [RFC1179] | McLaughlin, L., "Line printer daemon protocol", RFC 1179, August 1990. |
| [RFC7525] | Sheffer, Y., Holz, R. and P. Saint-Andre, "Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", BCP 195, RFC 7525, May 2015. |
The following is an example of a Print-Job request with "job-name", "copies", and "sides" specified. The "ipp-attribute-fidelity" attribute is set to 'true' so that the print request will fail if the "copies" or the "sides" attribute are not supported or their values are not supported.
| Octets | Symbolic Value | Protocol field |
|---|---|---|
| 0x0101 | 1.1 | version-number |
| 0x0002 | Print-Job | operation-id |
| 0x00000001 | 1 | request-id |
| 0x01 | start operation-attributes | operation-attributes-tag |
| 0x47 | charset type | value-tag |
| 0x0012 | name-length | |
| attributes-charset | attributes-charset | name |
| 0x0005 | value-length | |
| utf-8 | UTF-8 | value |
| 0x48 | natural-language type | value-tag |
| 0x001B | name-length | |
| attributes-natural-language | attributes-natural-language | name |
| 0x0005 | value-length | |
| en-us | en-US | value |
| 0x45 | uri type | value-tag |
| 0x000B | name-length | |
| printer-uri | printer-uri | name |
| 0x002C | value-length | |
| ipp://printer.example.com/ipp/print/pinetree | printer pinetree | value |
| 0x42 | nameWithoutLanguage type | value-tag |
| 0x0008 | name-length | |
| job-name | job-name | name |
| 0x0006 | value-length | |
| foobar | foobar | value |
| 0x22 | boolean type | value-tag |
| 0x0016 | name-length | |
| ipp-attribute-fidelity | ipp-attribute-fidelity | name |
| 0x0001 | value-length | |
| 0x01 | true | value |
| 0x02 | start job-attributes | job-attributes-tag |
| 0x21 | integer type | value-tag |
| 0x0006 | name-length | |
| copies | copies | name |
| 0x0004 | value-length | |
| 0x00000014 | 20 | value |
| 0x44 | keyword type | value-tag |
| 0x0005 | name-length | |
| sides | sides | name |
| 0x0013 | value-length | |
| two-sided-long-edge | two-sided-long-edge | value |
| 0x03 | end-of-attributes | end-of-attributes-tag |
| %!PDF... | <PDF Document> | data |
Here is an example of a successful Print-Job response to the previous Print-Job request. The Printer supported the "copies" and "sides" attributes and their supplied values. The status code returned is 'successful-ok'.
| Octets | Symbolic Value | Protocol field |
|---|---|---|
| 0x0101 | 1.1 | version-number |
| 0x0000 | successful-ok | status-code |
| 0x00000001 | 1 | request-id |
| 0x01 | start operation-attributes | operation-attributes-tag |
| 0x47 | charset type | value-tag |
| 0x0012 | name-length | |
| attributes-charset | attributes-charset | name |
| 0x0005 | value-length | |
| utf-8 | UTF-8 | value |
| 0x48 | natural-language type | value-tag |
| 0x001B | name-length | |
| attributes-natural-language | attributes-natural-language | name |
| 0x0005 | value-length | |
| en-us | en-US | value |
| 0x41 | textWithoutLanguage type | value-tag |
| 0x000E | name-length | |
| status-message | status-message | name |
| 0x000D | value-length | |
| successful-ok | successful-ok | value |
| 0x02 | start job-attributes | job-attributes-tag |
| 0x21 | integer | value-tag |
| 0x0006 | name-length | |
| job-id | job-id | name |
| 0x0004 | value-length | |
| 147 | 147 | value |
| 0x45 | uri type | value-tag |
| 0x0007 | name-length | |
| job-uri | job-uri | name |
| 0x0030 | value-length | |
| ipp://printer.example.com/ipp/print/pinetree/147 | job 147 on pinetree | value |
| 0x23 | enum type | value-tag |
| 0x0009 | name-length | |
| job-state | job-state | name |
| 0x0004 | value-length | |
| 0x0003 | pending | value |
| 0x03 | end-of-attributes | end-of-attributes-tag |
Here is an example of an unsuccessful Print-Job response to the previous Print-Job request. It fails because, in this case, the Printer does not support the "sides" attribute and because the value '20' for the "copies" attribute is not supported. Therefore, no Job is created, and neither a "job-id" nor a "job-uri" operation attribute is returned. The error code returned is 'client-error-attributes-or-values-not-supported' (0x040B).
| Octets | Symbolic Value | Protocol field |
|---|---|---|
| 0x0101 | 1.1 | version-number |
| 0x040B | client-error-attributes-or-values-not-supported | status-code |
| 0x00000001 | 1 | request-id |
| 0x01 | start operation-attributes | operation-attributes tag |
| 0x47 | charset type | value-tag |
| 0x0012 | name-length | |
| attributes-charset | attributes-charset | name |
| 0x0005 | value-length | |
| utf-8 | UTF-8 | value |
| 0x48 | natural-language type | value-tag |
| 0x001B | name-length | |
| attributes-natural-language | attributes-natural-language | name |
| 0x0005 | value-length | |
| en-us | en-US | value |
| 0x41 | textWithoutLanguage type | value-tag |
| 0x000E | name-length | |
| status-message | status-message | name |
| 0x002F | value-length | |
| client-error-attributes-or-values-not-supported | client-error-attributes-or-values-not-supported | value |
| 0x05 | start unsupported-attributes | unsupported-attributes tag |
| 0x21 | integer type | value-tag |
| 0x0006 | name-length | |
| copies | copies | name |
| 0x0004 | value-length | |
| 0x00000014 | 20 | value |
| 0x10 | unsupported (type) | value-tag |
| 0x0005 | name-length | |
| sides | sides | name |
| 0x0000 | value-length | |
| 0x03 | end-of-attributes | end-of-attributes-tag |
Here is an example of a successful Print-Job response to a Print-Job request like the previous Print-Job request, except that the value of "ipp-attribute-fidelity" is 'false'. The print request succeeds, even though, in this case, the Printer supports neither the "sides" attribute nor the value '20' for the "copies" attribute. Therefore, a Job is created, and both a "job-id" and a "job-uri" operation attribute are returned. The unsupported attributes are also returned in an Unsupported Attributes Group. The error code returned is 'successful-ok-ignored-or-substituted-attributes' (0x0001).
| Octets | Symbolic Value | Protocol field |
|---|---|---|
| 0x0101 | 1.1 | version-number |
| 0x0001 | successful-ok-ignored-or-substituted-attributes | status-code |
| 0x00000001 | 1 | request-id |
| 0x01 | start operation-attributes | operation-attributes-tag |
| 0x47 | charset type | value-tag |
| 0x0012 | name-length | |
| attributes-charset | attributes-charset | name |
| 0x0005 | value-length | |
| utf-8 | UTF-8 | value |
| 0x48 | natural-language type | value-tag |
| 0x001B | name-length | |
| attributes-natural-language | attributes-natural-language | name |
| 0x0005 | value-length | |
| en-us | en-US | value |
| 0x41 | textWithoutLanguage type | value-tag |
| 0x000E | name-length | |
| status-message | status-message | name |
| 0x002F | value-length | |
| successful-ok-ignored-or-substituted-attributes | successful-ok-ignored-or-substituted-attributes | value |
| 0x05 | start unsupported-attributes | unsupported-attributes tag |
| 0x21 | integer type | value-tag |
| 0x0006 | name-length | |
| copies | copies | name |
| 0x0004 | value-length | |
| 0x00000014 | 20 | value |
| 0x10 | unsupported (type) | value-tag |
| 0x0005 | name-length | |
| sides | sides | name |
| 0x0000 | value-length | |
| 0x02 | start job-attributes | job-attributes-tag |
| 0x21 | integer | value-tag |
| 0x0006 | name-length | |
| job-id | job-id | name |
| 0x0004 | value-length | |
| 147 | 147 | value |
| 0x45 | uri type | value-tag |
| 0x0007 | name-length | |
| job-uri | job-uri | name |
| 0x0030 | value-length | |
| ipp://printer.example.com/ipp/print/pinetree/147 | job 147 on pinetree | value |
| 0x23 | enum type | value-tag |
| 0x0009 | name-length | |
| job-state | job-state | name |
| 0x0004 | value-length | |
| 0x0003 | pending | value |
| 0x03 | end-of-attributes | end-of-attributes-tag |
The following is an example of Print-URI request with "copies" and "job-name" parameters:
| Octets | Symbolic Value | Protocol field |
|---|---|---|
| 0x0101 | 1.1 | version-number |
| 0x0003 | Print-URI | operation-id |
| 0x00000001 | 1 | request-id |
| 0x01 | start operation-attributes | operation-attributes-tag |
| 0x47 | charset type | value-tag |
| 0x0012 | name-length | |
| attributes-charset | attributes-charset | name |
| 0x0005 | value-length | |
| utf-8 | UTF-8 | value |
| 0x48 | natural-language type | value-tag |
| 0x001B | name-length | |
| attributes-natural-language | attributes-natural-language | name |
| 0x0005 | value-length | |
| en-us | en-US | value |
| 0x45 | uri type | value-tag |
| 0x000B | name-length | |
| printer-uri | printer-uri | name |
| 0x002C | value-length | |
| ipp://printer.example.com/ipp/print/pinetree | printer pinetree | value |
| 0x45 | uri type | value-tag |
| 0x000C | name-length | |
| document-uri | document-uri | name |
| 0x0019 | value-length | |
| ftp://foo.example.com/foo | ftp://foo.example.com/foo | value |
| 0x42 | nameWithoutLanguage type | value-tag |
| 0x0008 | name-length | |
| job-name | job-name | name |
| 0x0006 | value-length | |
| foobar | foobar | value |
| 0x02 | start job-attributes | job-attributes-tag |
| 0x21 | integer type | value-tag |
| 0x0006 | name-length | |
| copies | copies | name |
| 0x0004 | value-length | |
| 0x00000001 | 1 | value |
| 0x03 | end-of-attributes | end-of-attributes-tag |
The following is an example of Create-Job request with no parameters and no attributes:
| Octets | Symbolic Value | Protocol field |
|---|---|---|
| 0x0101 | 1.1 | version-number |
| 0x0005 | Create-Job | operation-id |
| 0x00000001 | 1 | request-id |
| 0x01 | start operation-attributes | operation-attributes-tag |
| 0x47 | charset type | value-tag |
| 0x0012 | name-length | |
| attributes-charset | attributes-charset | name |
| 0x0005 | value-length | |
| utf-8 | UTF-8 | value |
| 0x48 | natural-language type | value-tag |
| 0x001B | name-length | |
| attributes-natural-language | attributes-natural-language | name |
| 0x0005 | value-length | |
| en-us | en-US | value |
| 0x45 | uri type | value-tag |
| 0x000B | name-length | |
| printer-uri | printer-uri | name |
| 0x002C | value-length | |
| ipp://printer.example.com/ipp/print/pinetree | printer pinetree | value |
| 0x03 | end-of-attributes | end-of-attributes-tag |
The following is an example of Create-Job request with the "media-col" collection attribute [PWG5100.3] with the value "media-size={x-dimension=21000 y-dimension=29700} media-type='stationery'":
| Octets | Symbolic Value | Protocol field |
|---|---|---|
| 0x0101 | 1.1 | version-number |
| 0x0005 | Create-Job | operation-id |
| 0x00000001 | 1 | request-id |
| 0x01 | start operation-attributes | operation-attributes-tag |
| 0x47 | charset type | value-tag |
| 0x0012 | name-length | |
| attributes-charset | attributes-charset | name |
| 0x0005 | value-length | |
| utf-8 | UTF-8 | value |
| 0x48 | natural-language type | value-tag |
| 0x001B | name-length | |
| attributes-natural-language | attributes-natural-language | name |
| 0x0005 | value-length | |
| en-us | en-US | value |
| 0x45 | uri type | value-tag |
| 0x000B | name-length | |
| printer-uri | printer-uri | name |
| 0x002C | value-length | |
| ipp://printer.example.com/ipp/print/pinetree | printer pinetree | value |
| 0x34 | begCollection | value-tag |
| 0x0009 | 9 | name-length |
| media-col | media-col | name |
| 0x0000 | 0 | value-length |
| 0x4A | memberAttrName | value-tag |
| 0x0000 | 0 | name-length |
| 0x000A | 10 | value-length |
| media-size | media-size | value (member-name) |
| 0x34 | begCollection | member-value-tag |
| 0x0000 | 0 | name-length |
| 0x0000 | 0 | member-value-length |
| 0x4A | memberAttrName | value-tag |
| 0x0000 | 0 | name-length |
| 0x000B | 11 | value-length |
| x-dimension | x-dimension | value (member-name) |
| 0x21 | integer | member-value-tag |
| 0x0000 | 0 | name-length |
| 0x0004 | 4 | member-value-length |
| 0x00005208 | 21000 | member-value |
| 0x4A | memberAttrName | value-tag |
| 0x0000 | 0 | name-length |
| 0x000B | 11 | value-length |
| y-dimension | y-dimension | value (member-name) |
| 0x21 | integer | member-value-tag |
| 0x0000 | 0 | name-length |
| 0x0004 | 4 | member-value-length |
| 0x00007404 | 29700 | member-value |
| 0x37 | endCollection | end-value-tag |
| 0x0000 | 0 | end-name-length |
| 0x0000 | 0 | end-value-length |
| 0x4A | memberAttrName | value-tag |
| 0x0000 | 0 | name-length |
| 0x000A | 10 | value-length |
| media-type | media-type | value (member-name) |
| 0x44 | keyword | member-value-tag |
| 0x0000 | 0 | name-length |
| 0x000A | 10 | member-value-length |
| stationery | stationery | member-value |
| 0x37 | endCollection | end-value-tag |
| 0x0000 | 0 | end-name-length |
| 0x0000 | 0 | end-value-length |
| 0x03 | end-of-attributes | end-of-attributes-tag |
The following is an example of Get-Jobs request with parameters but no attributes:
| Octets | Symbolic Value | Protocol field |
|---|---|---|
| 0x0101 | 1.1 | version-number |
| 0x000A | Get-Jobs | operation-id |
| 0x0000007B | 123 | request-id |
| 0x01 | start operation-attributes | operation-attributes-tag |
| 0x47 | charset type | value-tag |
| 0x0012 | name-length | |
| attributes-charset | attributes-charset | name |
| 0x0005 | value-length | |
| utf-8 | UTF-8 | value |
| 0x48 | natural-language type | value-tag |
| 0x001B | name-length | |
| attributes-natural-language | attributes-natural-language | name |
| 0x0005 | value-length | |
| en-us | en-US | value |
| 0x45 | uri type | value-tag |
| 0x000B | name-length | |
| printer-uri | printer-uri | name |
| 0x002C | value-length | |
| ipp://printer.example.com/ipp/print/pinetree | printer pinetree | value |
| 0x21 | integer type | value-tag |
| 0x0005 | name-length | |
| limit | limit | name |
| 0x0004 | value-length | |
| 0x00000032 | 50 | value |
| 0x44 | keyword type | value-tag |
| 0x0014 | name-length | |
| requested-attributes | requested-attributes | name |
| 0x0006 | value-length | |
| job-id | job-id | value |
| 0x44 | keyword type | value-tag |
| 0x0000 | additional value | name-length |
| 0x0008 | value-length | |
| job-name | job-name | value |
| 0x44 | keyword type | value-tag |
| 0x0000 | additional value | name-length |
| 0x000F | value-length | |
| document-format | document-format | value |
| 0x03 | end-of-attributes | end-of-attributes-tag |
The following is an of Get-Jobs response from previous request with 3 jobs. The Printer returns no information about the second Job (because of security reasons):
| Octets | Symbolic Value | Protocol field |
|---|---|---|
| 0x0101 | 1.1 | version-number |
| 0x0000 | successful-ok | status-code |
| 0x0000007B | 123 | request-id (echoed back) |
| 0x01 | start operation-attributes | operation-attributes-tag |
| 0x47 | charset type | value-tag |
| 0x0012 | name-length | |
| attributes-charset | attributes-charset | name |
| 0x0005 | value-length | |
| utf-8 | UTF-8 | value |
| 0x48 | natural-language type | value-tag |
| 0x001B | name-length | |
| attributes-natural-language | attributes-natural-language | name |
| 0x0005 | value-length | |
| en-us | en-US | value |
| 0x41 | textWithoutLanguage type | value-tag |
| 0x000E | name-length | |
| status-message | status-message | name |
| 0x000D | value-length | |
| successful-ok | successful-ok | value |
| 0x02 | start job-attributes (1st object) | job-attributes-tag |
| 0x21 | integer type | value-tag |
| 0x0006 | name-length | |
| job-id | job-id | name |
| 0x0004 | value-length | |
| 147 | 147 | value |
| 0x36 | nameWithLanguage | value-tag |
| 0x0008 | name-length | |
| job-name | job-name | name |
| 0x000C | value-length | |
| 0x0005 | sub-value-length | |
| fr-ca | fr-CA | value |
| 0x0003 | sub-value-length | |
| fou | fou | name |
| 0x02 | start job-attributes (2nd object) | job-attributes-tag |
| 0x02 | start job-attributes (3rd object) | job-attributes-tag |
| 0x21 | integer type | value-tag |
| 0x0006 | name-length | |
| job-id | job-id | name |
| 0x0004 | value-length | |
| 148 | 149 | value |
| 0x36 | nameWithLanguage | value-tag |
| 0x0008 | name-length | |
| job-name | job-name | name |
| 0x0012 | value-length | |
| 0x0005 | sub-value-length | |
| de-CH | de-CH | value |
| 0x0009 | sub-value-length | |
| isch guet | isch guet | name |
| 0x03 | end-of-attributes | end-of-attributes-tag |
This section is strictly informative. The MIME media type listed in this section should not be re-registered by IANA when this document is published.
This appendix contains the information that IANA requires for registering a MIME media type. The information following this paragraph will be forwarded to IANA to register application/ipp whose contents are defined in Section 3 "Encoding of the Operation Layer" in this document:
MIME type name: application
MIME subtype name: ipp
A Content-Type of "application/ipp" indicates an Internet Printing Protocol message body (request or response) whose syntax is described in Section 3 "Encoding of the Operation Layer" of [RFC2910bis], and whose semantics are described in [RFC2911bis].
Required parameters: none
Optional parameters: none
Encoding considerations:
IPP protocol requests/responses MAY contain long lines and ALWAYS contain binary data (for example attribute value lengths).
Security considerations:
IPP protocol requests/responses do not introduce any security risks not already inherent in the underlying transport protocols. Protocol mixed-version interworking rules in [RFC2911bis] as well as protocol encoding rules in [RFC2910bis] are complete and unambiguous.
Interoperability considerations:
IPP requests (generated by clients) and responses (generated by servers) MUST comply with all conformance requirements imposed by the normative specifications [RFC2911bis] and [RFC2910bis]. Protocol encoding rules specified in [RFC2910bis] are comprehensive, so that interoperability between conforming implementations is guaranteed (although support for specific optional features is not ensured). Both the "charset" and "natural-language" of all IPP attribute values which are a LOCALIZED-STRING are explicit within IPP protocol requests/responses (without recourse to any external information in HTTP, SMTP, or other message transport headers).
Published specifications:
[RFC2911bis] Sweet, M., McDonald, I., "Internet Printing Protocol/1.1: Model and Semantics" draft-sweet-rfc2911bis-06.txt, December, 2015.
[RFC2910bis] Sweet, M., McDonald, I., "Internet Printing Protocol/1.1: Encoding and Transport", draft-sweet-rfc2910bis-07.txt, December, 2015.
Applications which use this media type:
Internet Printing Protocol (IPP) print clients and print servers, communicating using HTTP (see [RFC2910bis]), SMTP/ESMTP, FTP, or other transport protocol. Messages of type "application/ipp" are self-contained and transport-independent, including "charset" and "natural-language" context for any LOCALIZED-STRING value.
The authors would like to acknowledge the following individuals for their contributions to the original IPP/1.1 specification:
Robert Herriot (original RFC 2910 editor), Paul Moore, Sylvan Butler, Randy Turner, and John Wenn
The following changes are in draft-sweet-rfc2910bis-06:
The following changes are in draft-sweet-rfc2910bis-06:
The following changes are in draft-sweet-rfc2910bis-05:
The following changes are in draft-sweet-rfc2910bis-04:
The following changes are in draft-sweet-rfc2910bis-03:
The following changes are in draft-sweet-rfc2910bis-02:
The following changes are in draft-sweet-rfc2910bis-01: