Internet Printing Protocol WG Hugo Parra INTERNET-DRAFT Novell, Inc. Tom Hastings Updates: RFC 2910 and 2911 Xerox Corp. [Target Category: standards track] July 17, 2001 Expires: January 17, 2002 Internet Printing Protocol (IPP): The 'indp' Delivery Method for Event Notifications and Protocol/1.0 Copyright (C) The Internet Society (2001). All Rights Reserved. Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of [RFC2026]. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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". The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed as http://www.ietf.org/shadow.html. Abstract This document describes an extension to the Internet Printing Protocol/1.0 (IPP) [RFC2566, RFC2565] and IPP/1.1 [RFC2911, RFC2910]. This document specifies the 'indp' Delivery Method and Protocol/1.0 for use with the "IPP Event Notifications and Subscriptions" specification [ipp-ntfy]. When IPP Notification [ipp-ntfy] is supported, the Delivery Method defined in this document is one of the RECOMMENDED Delivery Methods for Printers to support. This Delivery Method is a simple protocol consisting of a single operation: the Send-Notifications operation which uses the same encoding and transport as IPP [RFC2565, RFC2910]. For this Delivery Method, when an Event occurs, the Printer immediately sends (pushes) an Event Notification via the Send-Notifications operation to the Parra, Hastings Expires: January 17, 2002 [page 1] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Notification Recipient specified in the Subscription Object. The Event Notification content consists of Machine Consumable attributes and a Human Consumable "notify-text" attribute. The Notification Recipient returns a response to the Printer. Parra, Hastings Expires: January 17, 2002 [page 2] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Table of Contents 1 Introduction.....................................................5 2 Terminology......................................................6 3 Model and Operation..............................................6 4 General Information..............................................7 5 Subscription object attributes..................................10 5.1 Subscription Template Attribute Conformance...................10 5.2 Additional Information about Subscription Template Attributes.10 5.2.1 notify-recipient-uri (uri)..................................10 5.3 Subscription Description Attribute Conformance................10 6 New Values for Existing Printer Description Attributes..........11 6.1 notify-schemes-supported (1setOf uriScheme)...................11 6.2 operations-supported (1setOf type2 enum)......................11 7 Attributes Only in Event Notifications..........................11 8 Operations for Notification.....................................12 8.1 Send-Notifications operation..................................12 8.1.1 Send-Notifications Request..................................12 8.1.2 Send-Notifications Response.................................17 9 Status Codes....................................................18 9.1 Additional Status Codes.......................................18 9.1.1 successful-ok-ignored-notifications (0x0004)................19 9.1.2 client-error-ignored-all-notifications (0x0416).............19 9.2 Status Codes returned in Event Notification Attributes Groups.19 9.2.1 client-error-not-found (0x0406).............................19 9.2.2 successful-ok-but-cancel-subscription (0x0006)..............20 10 Encoding and Transport.........................................20 10.1 Encoding of the Operation Layer..............................20 10.2 Encoding of Transport Layer..................................20 11 Conformance Requirements.......................................20 11.1 Conformance Requirements for Printers........................21 11.2 Conformance Requirements for INDP Notification Recipients....21 12 INDP URL Scheme................................................22 12.1 INDP URL Scheme Applicability and Intended Usage.............22 Parra, Hastings Expires: January 17, 2002 [page 3] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 12.2 INDP URL Scheme Associated INDP Port.........................22 12.3 INDP URL Scheme Associated MIME Type.........................22 12.4 INDP URL Scheme Character Encoding...........................22 12.5 INDP URL Scheme Syntax in ABNF...............................23 12.5.1 INDP URL Examples..........................................23 12.5.2 INDP URL Comparisons.......................................24 13 IANA Considerations............................................24 13.1 Operation Registrations......................................25 13.2 Additional attribute value registrations for existing attributes 25 13.2.1 Additional values for the "notify-schemes-supported" Printer attribute..............................................25 13.2.2 Additional values for the "operations-supported" Printer attribute..............................................26 13.3 Status code Registrations....................................26 14 Internationalization Considerations............................26 15 Security Considerations........................................27 15.1 Security Conformance.........................................27 16 References.....................................................28 17 Author's Addresses.............................................29 18 Summary of Base IPP documents..................................30 19 Full Copyright Statement.......................................32 Tables Table 1 - Information about the Delivery Method....................8 Table 2 - Operation-id assignments................................11 Table 3 - Attributes in Event Notification Content................15 Table 4 - Additional Attributes in Event Notification Content for Job Events ........................................................16 Table 5 - Combinations of Events and Subscribed Events for "job- impressions-completed" ........................................16 Table 6 - Additional Attributes in Event Notification Content for Printer Events ................................................17 Table 7 - The "event-notification-attributes-tag" value...........20 Parra, Hastings Expires: January 17, 2002 [page 4] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 1 Introduction The "IPP Event Notifications and Subscriptions" document [ipp-ntfy] defines an OPTIONAL extension to Internet Printing Protocol/1.0 (IPP) [RFC2566, RFC2565] and IPP/1.1 [RFC2911, RFC2910] (for a description of the base IPP documents, see section 18). That extension defines operations that a client can perform in order to create Subscription Objects in a Printer and carry out other operations on them. A Subscription Object represents a Subscription abstraction. A client associates Subscription Objects with a particular Job by performing the Create-Job-Subscriptions operation or by submitting a Job with subscription information. A client associates Subscription Objects with the Printer by performing a Create-Printer-Subscriptions operation. Four other operations are defined for Subscription Objects: Get-Subscriptions-Attributes, Get-Subscriptions, Renew- Subscription, and Cancel-Subscription. The Subscription Object specifies that when one of the specified Events occurs, the Printer sends an asynchronous Event Notification to the specified Notification Recipient via the specified Delivery Method (i.e., protocol). The "IPP Event Notifications and Subscriptions" document [ipp-ntfy] specifies that each Delivery Method is defined in another document. This document is one such document, and it specifies the 'indp' Delivery Method. When IPP Notification [ipp-ntfy] is supported, the Delivery Method defined in this document is one of the RECOMMENDED Delivery Methods for Printers to support. This Delivery Method is a simple protocol consisting of a single operation: the Send- Notifications operation which uses the same encoding and transport as IPP. This document defines version '1.0' of the protocol. For the 'indp' Delivery Method, an IPP Printer sends (pushes) a Send- Notifications operation request containing one or more Event Notifications to the Notification Recipient specified in the Subscription Object. The Event Notification content consists of Machine Consumable attributes and a Human Consumable "notify-text" attribute. The Notification Recipient receives the Event Notification as a Send- Notifications operation, in the same way as an IPP Printer receives IPP operations. The Notification Recipient returns a response to the Printer. Parra, Hastings Expires: January 17, 2002 [page 5] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 2 Terminology This section defines the following terms that are used throughout this document: This document uses the same terminology as [RFC2911], such as "client", "Printer", "attribute", "attribute value", "keyword", "operation", "request", "response", and "support". Capitalized terms, such as MUST, MUST NOT, REQUIRED, SHOULD, SHOULD NOT, MAY, NEED NOT, and OPTIONAL, have special meaning relating to conformance as defined in RFC 2119 [RFC2119] and [RFC2911] section 12.1. If an implementation supports the extension defined in this document, then these terms apply; otherwise, they do not. These terms define conformance to this document only; they do not affect conformance to other documents, unless explicitly stated otherwise. Event Notification Attributes Group - The attributes group in a request that contains Event Notification Attributes in a request or response. Other capitalized terms, such as Notification Recipient, Event Notification, Compound Event Notification, Printer, etc., are defined in [ipp-ntfy], have the same meanings, and are not reproduced here. 3 Model and Operation See [ipp-ntfy] for the description of the Event Notification Model and Operation. This Delivery Method takes advantage of combining several Event Notifications into a single Compound Event Notification that is delivery by a single Send-Notification operation to a single Notification Recipient. When creating each Subscription object, the client supplies the "notify-recipient" (uri) Subscription Template attribute. The "notify-recipient" attribute specifies both a single Notification Recipient that is to receive the Notifications when subsequent events occur and the method for notification delivery that the IPP Printer is to use. For the Notification Delivery Method defined in this document, the notification method is 'indp' and the rest of the URI is the address of the Notification Recipient to which the IPP Printer will send the Send-Notifications operation. The 'indp' Notification Delivery Method defined in this document uses a client/server protocol paradigm. The "client" in this relationship Parra, Hastings Expires: January 17, 2002 [page 6] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 is the Printer described in [ipp-ntfy] while the "server" is the Notification Recipient. The Printer invokes the Send-Notifications operation to communicate IPP Event Notification contents to the Notification Recipient. The Notification Recipient only conveys information to the Printer in the form of responses to the operations initiated by the Printer. Printers that implement the 'indp' Notification Delivery Method will need to include an HTTP client stack while Notification Recipients that implement this Delivery Method will need to support an HTTP server stack. See section 10.2 for more details. If the client wants the Printer to send Event Notifications via the 'indp' Delivery Method, the client MUST choose a value for "notify- recipient-uri" attribute which conforms to the rules of section 5.2.1. When an Event occurs, the Printer MUST immediately: 1.Find all pertinent Subscription Objects P according to the rules of section 9 of [ipp-ntfy], AND 2.Find the subset M of these Subscription Objects P whose "notify- recipient-uri" attribute has a scheme value of 'indp', AND 3.For each Subscription Object in M, the Printer MUST a)generate a Send-Notifications request as specified in section 8.1.1 AND b)send the Send-Notifications request to the Notification Recipient specified by the address part of the "notify- recipient-uri" attribute value (see section 5.2.1). If several events occur sufficiently close to one another for the same or different Subscription objects, but with the same Notification Recipient, the Printer MAY combine them into a single Send-Notifications request using a separate Event Notification Attributes group for each event (see section 8.1.1). 4 General Information If a client or Printer supports this Delivery Method, Table 1 lists its characteristics. Parra, Hastings Expires: January 17, 2002 [page 7] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Table 1 - Information about the Delivery Method Document Method conformance 'indp' realization requirement 1. What is the URL scheme name indp for the Delivery Method? 2. Is the Delivery Method is REQUIRED, RECOMMENDED, or OPTIONAL for an IPP Printer to support? RECOMMENDED 3. What transport and delivery protocol does the Printer use complete HTTP/1.1 stack to deliver the Event [RFC2616] Notification content, i.e., what is the entire network stack? A Printer MUST support a 4. Can several Event A Printer implementation MAY Notifications be combined into combine several Event a Compound Event Notification? Notifications into a single Event Notifications request as separate Event Notification Attributes Groups, see section 8.1.1 5. Is the Delivery Method This Delivery Method is a push. initiated by the Notification Recipient (pull), or by the Printer (push)? 6. Is the Event Notification Machine Consumable with the content Machine Consumable or "notify-text" attribute being Human Consumable? Human Consumable 7. What section in this document The representation and encoding answers the following is the same as IPP. See question? For a Machine section 8.1.1 Consumable Event Notification, what is the representation and encoding of values defined in section 9.1 of [ipp-ntfy] and the conformance requirements thereof? For a Human Parra, Hastings Expires: January 17, 2002 [page 8] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Document Method conformance 'indp' realization requirement thereof? For a Human Consumable Event Notification, what is the representation and encoding of pieces of information defined in section 9.2 of [ipp-ntfy] and the conformance requirements thereof? 8. What are the latency and reliability of the transport itself (see [RFC2911]). and delivery protocol? Same as for IPP/1.0 or IPP/1.1 9. What are the security aspects See section 15 of the transport and delivery protocol, e.g., how it is handled in firewalls? 10. What are the content length They are the same as for restrictions? IPP/1.0 and IPP/1.1 itself (see [RFC2911]). 11. What are the additional values A new Event Notifications or pieces of information that attribute group (see section a Printer sends in an Event 10.1) and additional status Notification and the codes for use in the response conformance requirements (see section 9) thereof? 12. What are the additional None Subscription Template and/or Subscription Description attributes and the conformance requirements thereof? 13. What are the additional None Printer Description attributes and the conformance requirements thereof? The remaining sections of this document parallel the sections of [ipp-ntfy]. Parra, Hastings Expires: January 17, 2002 [page 9] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 5 Subscription object attributes This section defines the Subscription object conformance requirements for Printers. 5.1 Subscription Template Attribute Conformance The 'indp' Delivery Method has the same conformance requirements for Subscription Template attributes as defined in [ipp-ntfy]. The 'indp' Delivery Method does not define any addition Subscription Template attributes. 5.2 Additional Information about Subscription Template Attributes This section defines additional information about Subscription Template attributes defined in [ipp-ntfy]. 5.2.1 notify-recipient-uri (uri) This section describes the syntax of the value of this attribute for the 'indp' Delivery Method. The syntax for values of this attribute for other Delivery Method is defined in other Delivery Method Documents. In order to support the 'indp' Delivery Method and Protocol, the Printer MUST support the following syntax: The 'indp://' URI scheme. The remainder of the URI indicates the host name or host address (and optional path) of the Notification Recipient that is to receive the Send- Notification operation. See section 12 for a complete definition of the syntax of the INDP URL. 5.3 Subscription Description Attribute Conformance The 'indp' Delivery Method has the same conformance requirements for Subscription Description attributes as defined in [ipp-ntfy]. The 'indp' Delivery Method does not define any addition Subscription Description attributes. Parra, Hastings Expires: January 17, 2002 [page 10] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 6 New Values for Existing Printer Description Attributes This Delivery Method does not define any additional Printer Description attribute from those defined in [ipp-ntfy]. However, it does define additional values for existing Printer Description attributes defined in [ipp-ntfy]. This section defines those additional values. 6.1 notify-schemes-supported (1setOf uriScheme) The following value of the "notify-schemes-supported" Printer attribute (see [ipp-ntfy] section 5.3.1) is added in order to support the new Delivery Method defined in this document: 'indp' - The IPP Notification Delivery Method defined in this document. 6.2 operations-supported (1setOf type2 enum) Table 2 lists the value of the "operation-id" operation parameter (see [RFC2911]) and the value of the "operations-supported" Printer Description attribute (see [RFC2911]) added in order to support the new operation defined in this document. The operation-id is assigned in the same name space as other operations that a Printer supports. However, a Printer MUST NOT include this value in its "operations- supported" attribute unless it can accept the Send-Notifications request. Table 2 - Operation-id assignments Value Operation Name 0x001D Send-Notifications 7 Attributes Only in Event Notifications No additional attributes are defined only for use in Event Notifications besides those defined in [ipp-ntfy]. Parra, Hastings Expires: January 17, 2002 [page 11] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 8 Operations for Notification This section defines the operation for Event Notification using the 'indp' Delivery Method. There is only one operation defined: Send-Notifications. Section 6.2 assigns of the "operation-id" for the Send-Notifications operation and the following section defined the operation. 8.1 Send-Notifications operation This REQUIRED operation allows a Printer to send one or more Event Notifications to a Notification Recipient using HTTP. The Printer composes the information defined for an IPP Notification [ipp-ntfy] and sends it using the Send-Notifications operation to the Notification Recipient supplied in the Subscription object. The ordering of separate Send-Notifications operations that a Printer sends MUST follow the "Event Notification Ordering" requirements in [ipp-ntfy] section 9. The Send-Notifications operation uses the operations model defined by IPP [RFC2566]. This includes, the use of a URI as the identifier for the target of each operation, the inclusion of a version number, operation-id, and request-id in each request, and the definition of attribute groups. The Send-Notifications operation uses the Operation Attributes group, but currently has no need for the Unsupported Attributes, Printer Object Attributes, and Job-Object Attributes groups. However, it uses a new attribute group, the Event Notification Attributes group. The Notification Recipient MUST accept the request in any state. There is no state defined for the Notification Recipient for this Delivery Method. Access Rights: Notification Recipient MAY enforce access rights. If the Printer receives a rejection with these status codes: 'client- error-forbidden', 'client-error-not-authenticated', or 'client-error- not-authorized' status code , the Printer SHOULD cancel the subscription. 8.1.1 Send-Notifications Request Every operation request MUST contains the following parameters (see [RFC2911] section 3.1.1): Parra, Hastings Expires: January 17, 2002 [page 12] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 - a "version-number" '1.0' - the version of the 'indp' protocol is '1.0'. - an "operation-id" - the value defined in Table 2 - a "request-id" - the request id (see [RFC2911] section 3.1.2). The following groups of attributes MUST be part of the Send- Notifications Request: Group 1: Operation Attributes Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as defined in [RFC2911] section 3.1.4.1. The Printer MUST use the values of "notify-charset" and "notify-natural-language", respectively, from one Subscription Object associated with the Event Notifications in this request. Normally, there is only one matched Subscription Object, or the value of the "notify-charset" and "notify-natural-language" attributes is the same in all Subscription Objects. If not, the Printer MUST pick one Subscription Object from which to obtain the value of these attributes. The algorithm for picking the Subscription Object is implementation dependent. The choice of natural language is not critical because 'text' and 'name' values can override the "attributes-natural-language" Operation attribute. The Printer's choice of charset is critical because a bad choice may leave it unable to send some 'text' and 'name' values accurately. Target: A copy of the Subscription object's "notify-recipient-uri" (uri) attribute which is the target of this operation as described in [RFC2911] section 3.1.5, i.e., the URI of the 'indp' Notification Recipient (see section 5.2.1). Group 2 to N: Event Notification Attributes In each group 2 to N, each attribute is encoded using the IPP rules for encoding attributes [RFC2910] and the attributes within a group MAY be encoded in any order. Note: the Get-Jobs response in [RFC2911] acts as a model for encoding multiple groups of attributes. The entire request is considered a single Compound Event Notification and MUST follow the "Event Notification Ordering" requirements for Event Notifications within a Compound Event Notification specified in [ipp-ntfy] section 9. Parra, Hastings Expires: January 17, 2002 [page 13] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Each Event Notification Group MUST contain all of attributes specified in [ipp-ntfy] section 9.1 ("Content of Machine Consumable Event Notifications") with exceptions denoted by asterisks in the tables below. The tables below are copies of the tables in [ipp-ntfy] section 9.1 ("Content of Machine Consumable Event Notifications") except that each cell in the "Sends" column is a "MUST". For an Event Notification for all Events, the Printer sends the following attributes. Parra, Hastings Expires: January 17, 2002 [page 14] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Table 3 - Attributes in Event Notification Content Source Value Sends Source Object notify-subscription-id (integer(1:MAX)) MUST Subscription notify-printer-uri (uri) MUST Subscription notify-subscribed-event (type2 keyword) MUST Event Notification printer-up-time (integer(MIN:MAX)) MUST Printer printer-current-time (dateTime) MUST * Printer notify-sequence-number (integer (0:MAX)) MUST Subscription notify-charset (charset) MUST Subscription notify-natural-language (naturalLanguage) MUST Subscription notify-user-data (octetString(63)) MUST ** Subscription notify-text (text (MAX)) MUST Event Notification attributes from the "notify-attributes" MUST *** Printer attribute, if any attributes from the "notify-attributes" MUST *** Job attribute, if any attributes from the "notify-attributes" MUST *** Subscription attribute, if any * The Printer MUST send "printer-current-time" if and only if it supports the "printer-current-time" attribute on the Printer object. ** If the associated Subscription Object does not contain a "notify-user-data" attribute, the Printer MUST send an octet- string of length 0. *** If the "notify-attributes" attribute is present on the Subscription Object, the Printer MUST send all attributes Parra, Hastings Expires: January 17, 2002 [page 15] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 specified by the "notify-attributes" attribute. Note: if the Printer doesn't support the "notify-attributes" attribute, it is not present on the associated Subscription Object and the Printer does not send any client-requested attributes. For Event Notifications for Job Events, the Printer sends the following additional attributes shown in Table 4. Table 4 - Additional Attributes in Event Notification Content for Job Events Source Value Sends Source Object job-id (integer(1:MAX)) MUST Job job-state (type1 enum) MUST Job job-state-reasons (1setOf type2 keyword) MUST Job job-impressions-completed (integer(0:MAX)) MUST * Job * The Printer MUST send the "job-impressions-completed" attribute in an Event Notification only for the combinations of Events and Subscribed Events shown in Table 5. Table 5 - Combinations of Events and Subscribed Events for "job- impressions-completed" Job Event Subscribed Job Event 'job-progress' 'job-progress' 'job-completed' 'job-completed' 'job-completed' 'job-state-changed' For Event Notification for Printer Events, the Printer sends the following additional attributes shown in Table 6. Parra, Hastings Expires: January 17, 2002 [page 16] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Table 6 - Additional Attributes in Event Notification Content for Printer Events Source Value Sends Source Object printer-state (type1 enum) MUST Printer printer-state-reasons (1setOf type2 keyword) MUST Printer printer-is-accepting-jobs (boolean) MUST Printer 8.1.2 Send-Notifications Response The Notification Recipient MUST return (to the client which is the Printer) the following sets of attributes as part of a Send- Notifications response: Every operation response contains the following REQUIRED parameters (see [RFC2911] section 3.1.1}: - a "version-number" - a "status-code" - the "request-id" that was supplied in the corresponding request Group 1: Operation Attributes Status Message: As defined in [RFC2911]. The Notification Recipient can return any status codes defined in [RFC2911] and section 9.1 that applies to all of the Event Notification Attribute groups. The following is a description of the important status codes: 'successful-ok': the Notification Recipient received all of the Event Notification Attribute Groups and was expecting each of them. 'successful-ok-ignored-notifications': the Notification Recipient was able to consume some, but not all of the Event Notification Attributes Groups sent. The Event Notification Attributes Groups with a "notify-status- code" attribute are the ones that were ignored or are to be canceled. Parra, Hastings Expires: January 17, 2002 [page 17] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 'client-error-ignored-all-notifications': the Notification Recipient was unable to consume any of the Event Notification Attributes Groups sent. The Event Notification Attributes Groups with a "notify-status- code" attribute are the ones that were ignored or are to be canceled. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as defined in [RFC2911] section 3.1.4.1. Group 2 to N: Notification Attributes These groups MUST be returned if and only if the "status-code" parameter returned in Group 1 is anything but the 'successful-ok' status code. "notify-status-code" (type2 enum) Indicates whether the Notification Recipient was able to consume the n-th Notification Report as follows: 'successful-ok' - this Event Notification Attribute Group was consumed 'client-error-not-found' - this Event Notification Attribute Group was not able to be consumed. The Printer MUST cancel the Subscription and MUST NOT attempt to send any further Event Notifications from the associated Subscription object. 'successful-ok-but-cancel-subscription' - the Event Notification Attribute Group was consumed, but the Notification Recipient wishes to cancel the Subscription object. The Printer MUST cancel the Subscription and MUST NOT attempt to send any further Event Notifications from the associated Subscription object. 9 Status Codes This section lists status codes whose meaning have been extended and/or defined for returning in Event Notification Attribute Groups as the value of the "notify-status-code" operation attribute. The code values are allocated in the same space as the status codes in [RFC2911]. 9.1 Additional Status Codes The following status codes are defined as extensions for Notification and are returned as the value of the "status-code" parameter in the Parra, Hastings Expires: January 17, 2002 [page 18] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Operation Attributes Group of a response (see [RFC2911] section 3.1.6.1). Operations in this document can also return the status codes defined in section 13 of [RFC2911]. The 'successful-ok' status code is an example of such a status code. 9.1.1 successful-ok-ignored-notifications (0x0004) The Notification Recipient was able to consume some, but not all, of the Event Notifications Attributes Groups sent by the Printer in the Send-Notifications request. See section 8.1.2 for further details. 9.1.2 client-error-ignored-all-notifications (0x0416) The Notification Recipient was unable to consume any of the Event Notification Attributes Groups sent by the Printer. The Event Notification Attributes Groups with a "notify-status-code" attribute are the ones that were ignored or are to be canceled. The Printer MAY remove subscriptions for future events which this client was unable to consume. 9.2 Status Codes returned in Event Notification Attributes Groups This section contains values of the "notify-status-code" attribute that the Notification Recipient returns in a Event Notification Attributes Group in a response when the corresponding Event Notification Attributes Group in the request: 1.was not consumed OR 2.was consumed, but the Notification Recipient wants to cancel the corresponding Subscription object The following sections are ordered in decreasing order of importance of the status-codes. 9.2.1 client-error-not-found (0x0406) This status code is defined in [RFC2911]. This document extends its meaning and allows it to be returned in an Event Notification Attributes Group of a response. The Notification Recipient was unable to consume this Event Notification Attributes Group because it was not expected. See section 8.1.2 for further details. Parra, Hastings Expires: January 17, 2002 [page 19] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 9.2.2 successful-ok-but-cancel-subscription (0x0006) The Notification Recipient was able to consume this Event Notification Attributes Group that the Printer sent, but wants the corresponding Subscription object to be canceled none-the-less. See section 8.1.2 for further details. 10 Encoding and Transport This section defines the encoding and transport used by the 'indp' Delivery Method. 10.1 Encoding of the Operation Layer The 'indp' Delivery Method uses the IPP operation layer encoding described in [RFC2910] and the Event Notification Attributes Group tag allocated by [ipp-ntfy] as shown in Table 7: Table 7 - The "event-notification-attributes-tag" value Tag Value (Hex) Meaning 0x07 "event-notification-attributes-tag" 10.2 Encoding of Transport Layer The 'indp' Notification Delivery Method uses the IPP transport layer encoding described in [RFC2910]. It is REQUIRED that an 'indp' Notification Recipient implementation support HTTP over the IANA-assigned well known system port assigned to the 'indp' Delivery Method as its default port by IANA (see section 13), though a Notification Recipient implementation MAY support HTTP over some other port as well. 11 Conformance Requirements This section defines conformance requirements for Printers and Notification Recipients. Parra, Hastings Expires: January 17, 2002 [page 20] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 11.1 Conformance Requirements for Printers The 'indp' Delivery Method is RECOMMENDED for a Printer to support. IPP Printers that conform to this specification: 1.MUST meet the conformance requirements defined in [ipp-ntfy]. 2.MUST support the conformance requirements for Subscription object attributes defined in section 5, including the syntax for the "notify-recipient-uri" Subscription Object attribute defined in section 5.2.1. 3.MUST support the conformance requirements for Printer Description object attributes defined in section 6. 4.MUST support the 'indp' protocol by sending Event Notifications using the Send-Notifications operation defined in section 8.1. 5.MUST send INDP URLs (e.g., in the "notify-recipient-uri" attribute in 'Send-Notifications') that conform to the ABNF specified in section 12.5 of this document; 6.MUST send the Send-Notifications operation via the port specified in the INDP URL (if present) or otherwise via the IANA-assigned well-known system port xxx [TBA by IANA]; 7.MUST convert INDP URLs for use in the Send-Notifications operation to their corresponding HTTP URL forms for use in the HTTP layer by the same rules used to convert IPP URLs to their corresponding HTTP URL forms (see section 5 'IPP URL Scheme' in [RFC2910]). 11.2 Conformance Requirements for INDP Notification Recipients INDP Notification Recipients that conform to this specification: 1.MUST accept Send-Notifications requests and return Send- Notifications responses as defined in sections 8 and 9. 2.SHOULD reject received INDP URLs in "application/ipp" request bodies (e.g., in the "notify-recipient-uri" attribute in 'Send- Notifications') that do not conform to the ABNF for INDP URLs specified in section 12.5 of this document; 3.MUST listen for INDP operations on IANA-assigned well-known system port xxx [TBA by IANA], unless explicitly configured by system administrators or site policies; Parra, Hastings Expires: January 17, 2002 [page 21] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 4.SHOULD NOT listen for INDP operations on any other port, unless explicitly configured by system administrators or site policies. 12 INDP URL Scheme 12.1 INDP URL Scheme Applicability and Intended Usage This section is intended for use in registering the "indp" URL scheme with IANA and fully conforms to the requirements in [RFC2717]. This document defines the "indp" URL (Uniform Resource Locator) scheme for specifying the location of an INDP Notification Recipient object which implements IPP Notification Delivery Protocol (INDP) specified in this document. The intended usage of the "indp" URL scheme is COMMON. 12.2 INDP URL Scheme Associated INDP Port All INDP URLs which do NOT explicitly specify a port MUST be used over IANA-assigned well-known system port xxx [TBA by IANA] for the INDP protocol. See: IANA Port Numbers Registry [IANA-PORTREG]. 12.3 INDP URL Scheme Associated MIME Type All INDP protocol operations (requests and responses) MUST be conveyed in an "application/ipp" MIME media type as registered in [IANA-MIMEREG]. INDP URLs MUST refer to INDP Notification Recipient objects which support this "application/ipp" MIME media type. See: IANA MIME Media Types Registry [IANA-MIMEREG]. 12.4 INDP URL Scheme Character Encoding The INDP URL scheme defined in this document is based on the ABNF for the HTTP URL scheme defined in HTTP/1.1 [RFC2616], which is derived from the URI Generic Syntax [RFC2396] and further updated by [RFC2732] and [RFC2373] (for IPv6 addresses in URLs). The INDP URL scheme is case-insensitive in the 'scheme' and 'host' (host name or host address) part; however the 'abs_path' part is case-sensitive, as in [RFC2396]. Code points outside [US-ASCII] MUST be hex escaped by the mechanism specified in [RFC2396]. Parra, Hastings Expires: January 17, 2002 [page 22] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 12.5 INDP URL Scheme Syntax in ABNF The IPP protocol places a limit of 1023 octets (NOT characters) on the length of a URI (see section 4.1.5 'uri' in [RFC2911]). An INDP Notification Recipient MUST return 'client-error-request-value-too- long' (see section 13.1.4.10 in [RFC2911]) when a URI received in a request is too long. Note: INDP Notification Recipients ought to be cautious about depending on URI lengths above 255 bytes, because some older client or proxy implementations might not properly support these lengths. INDP URLs MUST be represented in absolute form. Absolute URLs always begin with a scheme name followed by a colon. For definitive information on URL syntax and semantics, see "Uniform Resource Identifiers (URI): Generic Syntax and Semantics" [RFC2396]. This specification adopts the definitions of "port", "host", "abs_path", and "query" from [RFC2396], as updated by [RFC2732] and [RFC2373] (for IPv6 addresses in URLs). The INDP URL scheme syntax in ABNF is as follows: indp_URL = "indp:" "//" host [ ":" port ] [ abs_path [ "?" query ]] If the port is empty or not given, IANA-assigned well-known system port xxx [TBA by IANA] is assumed. The semantics are that the identified resource (see section 5.1.2 of [RFC2616]) is located at the INDP Notification Recipient listening for HTTP connections on that port of that host, and the Request-URI for the identified resource is 'abs_path'. Note: The use of IP addresses in URLs SHOULD be avoided whenever possible (see [RFC1900]). If the 'abs_path' is not present in the URL, it MUST be given as "/" when used as a Request-URI for a resource (see section 5.1.2 of [RFC2616]). If a proxy receives a host name which is not a fully qualified domain name, it MAY add its domain to the host name it received. If a proxy receives a fully qualified domain name, the proxy MUST NOT change the host name. 12.5.1 INDP URL Examples The following are examples of valid INDP URLs for Notification Recipient objects (using DNS host names): indp://abc.com Parra, Hastings Expires: January 17, 2002 [page 23] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 indp://abc.com/listener Note: The use of IP addresses in URLs SHOULD be avoided whenever possible (see [RFC1900]). The following literal IPv4 addresses: 192.9.5.5 ; IPv4 address in IPv4 style 186.7.8.9 ; IPv4 address in IPv4 style are represented in the following example INDP URLs: indp://192.9.5.5/listener indp://186.7.8.9/listeners/tom The following literal IPv6 addresses (conformant to [RFC2373]): ::192.9.5.5 ; IPv4 address in IPv6 style ::FFFF:129.144.52.38 ; IPv4 address in IPv6 style 2010:836B:4179::836B:4179 ; IPv6 address per RFC 2373 are represented in the following example INDP URLs: indp://[::192.9.5.5]/listener indp://[::FFFF:129.144.52.38]/listener indp://[2010:836B:4179::836B:4179]/listeners/tom 12.5.2 INDP URL Comparisons When comparing two INDP URLs to decide if they match or not, the comparer MUST use the same rules as those defined for HTTP URI comparisons in [RFC2616], with the sole following exception: ? A port that is empty or not given MUST be treated as equivalent to the well-known system port xxx [TBA by IANA] for that INDP URL; 13 IANA Considerations IANA shall register the indp URL scheme as defined in section 12 according to the procedures of [RFC2717] and assign a well-known system port. Parra, Hastings Expires: January 17, 2002 [page 24] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 The rest of this section contains the exact information for IANA to add to the IPP Registries according to the procedures defined in RFC 2911 [RFC2911] section 6. Note to RFC Editors: Replace RFC NNNN below with the RFC number for this document, so that it accurately reflects the content of the information for the IANA Registry. 13.1 Operation Registrations The following table lists the operation defined in this document. This is to be registered according to the procedures in RFC 2911 [RFC2911] section 6.4. Operations: Ref. Section: Send-Notifications operation RFC NNNN 8.1 The resulting operation registration will be published in the ftp://ftp.iana.org/in-notes/iana/assignments/ipp/operations/ area. 13.2 Additional attribute value registrations for existing attributes This section lists additional attribute value registrations for use with existing attributes defined in other documents. 13.2.1 Additional values for the "notify-schemes-supported" Printer attribute The following table lists the uriScheme value defined in this document as an additional uriScheme value for use with the "notify- schemes-supported" Printer attribute defined in [ipp-ntfy]. This is to be registered according to the procedures in RFC 2911 [RFC2911] section 6.1. uriScheme Attribute Values: Ref. Section: indp RFC NNNN 6.1 The resulting URI scheme attribute value registration will be published in the ftp://ftp.iana.org/in-notes/iana/assignments/ipp/attribute- values/notify-schemes-supported/ Parra, Hastings Expires: January 17, 2002 [page 25] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 area. 13.2.2 Additional values for the "operations-supported" Printer attribute The following table lists the enum attribute value defined in this document as an additional type2 enum value for use with the "operations-supported" Printer attribute defined in [RFC2911]. This is to be registered according to the procedures in RFC 2911 [RFC2911] section 6.1. type2 enum Attribute Values: Value Ref. Section: Send-Notifications 0x001D RFC NNNN 6.2 The resulting enum attribute value registration will be published in the ftp://ftp.iana.org/in-notes/iana/assignments/ipp/attribute- values/operations-supported/ area. 13.3 Status code Registrations The following table lists all the status codes defined in this document. These are to be registered according to the procedures in RFC 2911 [RFC2911] section 6.6. Status codes: Ref. Section: successful-ok-ignored-notifications (0x0004) RFC NNNN 9.1.1 client-error-ignored-all-notifications (0x0416) RFC NNNN 9.1.2 Status Codes in Event Notification Attributes Groups: client-error-not-found (0x0406) RFC NNNN 9.2.1 successful-ok-but-cancel-subscription (0x0006) RFC NNNN 9.2.2 The resulting status code registrations will be published in the ftp://ftp.iana.org/in-notes/iana/assignments/ipp/status-codes/ area. 14 Internationalization Considerations When the client requests Human Consumable form by supplying the "notify-text-format" operation attribute (see [ipp-ntfy]), the IPP Parra, Hastings Expires: January 17, 2002 [page 26] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Printer (or any Notification Service that the IPP Printer might be configured to use) supplies and localizes the text value of the "human-readable-report" attribute in the Notification according to the charset and natural language requested in the notification subscription. 15 Security Considerations The IPP Model and Semantics document [RFC2911] 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. The Notification Recipient can cancel unwanted Subscriptions created by other parties without having to be the owner of the subscription by returning the 'successful-ok-but-cancel-subscription' status code in the Send-Notifications response returned to the Printer. 15.1 Security Conformance Printers (client) MAY support Digest Authentication [RFC2617]. If Digest Authentication is supported, then MD5 and MD5-sess MUST be supported, but the Message Integrity feature NEED NOT be supported. Notification Recipient (server) MAY support Digest Authentication [RFC2617]. If Digest Authentication is supported, then MD5 and MD5- sess MUST be supported, but the Message Integrity feature NEED NOT be supported. Notification Recipients MAY support TLS for client authentication, server authentication and operation privacy. If a Notification Recipient supports TLS, it MUST support the TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA cipher suite as mandated by RFC 2246 [RFC2246]. All other cipher suites are OPTIONAL. Notification recipients MAY support Basic Authentication (described in HTTP/1.1 [RFC2616]) for client authentication if the channel is secure. TLS with the above mandated cipher suite can provide such a secure channel. Parra, Hastings Expires: January 17, 2002 [page 27] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 16 References [ipp-iig] Hastings, T., Manros, C., Kugler, K, Holst H., Zehler, P., "Internet Printing Protocol/1.1: draft-ietf-ipp-implementers- guide-v11-03.txt, work in progress, July 17, 2001 [ipp-ntfy] Isaacson, S., Martin, J., deBry, R., Hastings, T., Shepherd, M., Bergman, R., "Internet Printing Protocol/1.1: IPP Event Notifications and Subscriptions", , July 17, 2001. [IANA-MIMEREG] IANA MIME Media Types Registry. ftp://ftp.iana.org/in- notes/iana/assignments/media-types/ [IANA-PORTREG] IANA Port Numbers Registry. ftp://ftp.iana.org/in- notes/iana/assignments/port-numbers [RFC1900] B. Carpenter, Y. Rekhter. Renumbering Needs Work, RFC 1900, February 1996. [RFC2026] S. Bradner, "The Internet Standards Process -- Revision 3", RFC 2026, October 1996. [RFC2373] R. Hinden, S. Deering. IP Version 6 Addressing Architecture, RFC 2373, July 1998. [RFC2396] Berners-Lee, T. et al. Uniform Resource Identifiers (URI): Generic Syntax, RFC 2396, August 1998 [RFC2565] Herriot, R., Butler, S., Moore, P., and R. Turner, "Internet Printing Protocol/1.0: Encoding and Transport", RFC 2565, April 1999. Parra, Hastings Expires: January 17, 2002 [page 28] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 [RFC2566] R. deBry, T. Hastings, R. Herriot, S. Isaacson, and P. Powell, "Internet Printing Protocol/1.0: Model and Semantics", RFC 2566, April 1999. [RFC2567] Wright, D., "Design Goals for an Internet Printing Protocol", RFC 2567, April 1999. [RFC2568] Zilles, S., "Rationale for the Structure and Model and Protocol for the Internet Printing Protocol", RFC 2568, April 1999. [RFC2569] Herriot, R., Hastings, T., Jacobs, N., Martin, J., "Mapping between LPD and IPP Protocols", RFC 2569, April 1999. [RFC2616] R. Fielding, J. Gettys, J. Mogul, H. Frystyk, L. Masinter, P. Leach, T. Berners-Lee, "Hypertext Transfer Protocol - HTTP/1.1", RFC 2616, June 1999. [RFC2617] J. Franks, P. Hallam-Baker, J. Hostetler, S. Lawrence, P. Leach, A. Luotonen, L. Stewart, "HTTP Authentication: Basic and Digest Access Authentication", RFC 2617, June 1999. [RFC2717] R. Petke and I. King, "Registration Procedures for URL Scheme Names", RFC 2717, November 1999. [RFC2732] R. Hinden, B. Carpenter, L. Masinter. Format for Literal IPv6 Addresses in URL's, RFC 2732, December 1999. [RFC2910] Herriot, R., Butler, S., Moore, P., Tuner, R., "Internet Printing Protocol/1.1: Encoding and Transport", RFC 2910, September 2001. [RFC2911] R. deBry, T. Hastings, R. Herriot, S. Isaacson, P. Powell, "Internet Printing Protocol/1.1: Model and Semantics", RFC 2911, September 2001. 17 Author's Addresses Hugo Parra Parra, Hastings Expires: January 17, 2002 [page 29] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Novell, Inc. 1800 South Novell Place Provo, UT 84606 Phone: 801-861-3307 Fax: 801-861-2517 e-mail: hparra@novell.com Tom Hastings Xerox Corporation 737 Hawaii St. ESAE 231 El Segundo, CA 90245 Phone: 310-333-6413 Fax: 310-333-5514 e-mail: hastings@cp10.es.xerox.com IPP Web Page: http://www.pwg.org/ipp/ IPP Mailing List: ipp@pwg.org To subscribe to the ipp mailing list, send the following email: 1) send it to majordomo@pwg.org 2) leave the subject line blank 3) put the following two lines in the message body: subscribe ipp end Implementers of this specification document are encouraged to join the IPP Mailing List in order to participate in any discussions of clarification issues and review of registration proposals for additional attributes and values. In order to reduce spam the mailing list rejects mail from non-subscribers, so you must subscribe to the mailing list in order to send a question or comment to the mailing list. 18 Summary of Base IPP documents The base IPP documents includes: Design Goals for an Internet Printing Protocol [RFC2567] Rationale for the Structure and Model and Protocol for the Internet Printing Protocol [RFC2568] Internet Printing Protocol/1.1: Model and Semantics [RFC2911] Internet Printing Protocol/1.1: Encoding and Transport [RFC2910] Internet Printing Protocol/1.1: Implementer's Guide [ipp-iig] Parra, Hastings Expires: January 17, 2002 [page 30] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 Mapping between LPD and IPP Protocols [RFC2569] Internet Printing Protocol (IPP): IPP Event Notifications and Subscriptions [ipp-ntfy] The "Design Goals for an Internet Printing Protocol" document takes a broad look at distributed printing functionality, and it enumerates real-life scenarios that help to clarify the features that need to be included in a printing protocol for the Internet. It identifies requirements for three types of users: end users, operators, and administrators. It calls out a subset of end user requirements that are satisfied in IPP/1.0 [RFC2566, RFC2565]. A few OPTIONAL operator operations have been added to IPP/1.1 [RFC2911, RFC2910]. The "Rationale for the Structure and Model and Protocol for the Internet Printing Protocol" document describes IPP from a high level view, defines a roadmap for the various documents that form the suite of IPP specification documents, and gives background and rationale for the IETF working group's major decisions. The "Internet Printing Protocol/1.1: Model and Semantics" document describes a simplified model with abstract objects, their attributes, and their operations that are independent of encoding and transport. It introduces a Printer and a Job object. The Job object optionally supports multiple documents per Job. It also addresses security, internationalization, and directory issues. The "Internet Printing Protocol/1.1: Encoding and Transport" document is a formal mapping of the abstract operations and attributes defined in the model document onto HTTP/1.1 [RFC2616]. It defines the encoding rules for a new Internet MIME media type called "application/ipp". This document also defines the rules for transporting a message body over HTTP whose Content-Type is "application/ipp". This document defines the 'ipp' scheme for identifying IPP printers and jobs. The "Internet Printing Protocol/1.1: Implementer's Guide" document gives insight and advice to implementers of IPP clients and IPP objects. It is intended to help them understand IPP/1.1 and some of the considerations that may assist them in the design of their client and/or IPP object implementations. For example, a typical order of processing requests is given, including error checking. Motivation for some of the specification decisions is also included. The "Mapping between LPD and IPP Protocols" document gives some advice to implementers of gateways between IPP and LPD (Line Printer Daemon) implementations. Parra, Hastings Expires: January 17, 2002 [page 31] INTERNET-DRAFT IPP: The 'indp' Method and Protocol July 17, 2001 The "Internet Printing Protocol (IPP): IPP Event Notifications and Subscriptions" document defines an extension to IPP/1.0 [RFC2566, RFC2565] and IPP/1.1 [RFC2911, RFC2910]. This extension allows a client to subscribe to printing related Events by creating a Subscription Object and defines the semantics for delivering asynchronous Event Notifications to the specified Notification Recipient via a specified Delivery Method (i.e., protocols) defined in (separate) Delivery Method documents. 19 Full Copyright Statement Copyright (C) The Internet Society (2001). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Parra, Hastings Expires: January 17, 2002 [page 32]