SIPPING D. Petrie Internet-Draft SIPez LLC. Expires: January 18, 2006 July 17, 2005 A Framework for Session Initiation Protocol User Agent Profile Delivery draft-ietf-sipping-config-framework-07.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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 at http://www.ietf.org/shadow.html. This Internet-Draft will expire on January 18, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document defines the application of a set of protocols for providing profile data to SIP user agents. The objective is to define a means for automatically providing profile data a user agent needs to be functional without user or administrative intervention. The framework for discovery, delivery, notification and updates of user agent profile data is defined here. As part of this framework a new SIP event package is defined here for the notification of profile changes. This framework is also intended to ease ongoing administration and upgrading of large scale deployments of SIP user Petrie Expires January 18, 2006 [Page 1] Internet-Draft SIP UA Profile Framework July 2005 agents. The contents and format of the profile data to be defined is outside the scope of this document. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Requirements Terminology . . . . . . . . . . . . . . . . . . 4 3. Profile Delivery Framework Terminology . . . . . . . . . . . 4 4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.1 Service Provider Use Case Scenario Bootstrapping with Digest Authentication . . . . . . . . . . . . . . . . . . 7 5.2 Service Provider Use Case Scenario Bootstrapping with Device Certificate . . . . . . . . . . . . . . . . . . . . 9 6. Data Model . . . . . . . . . . . . . . . . . . . . . . . . . 9 7. Profile Change Event Notification Package . . . . . . . . . 11 7.1 Event Package Name . . . . . . . . . . . . . . . . . . . . 11 7.2 Event Package Parameters . . . . . . . . . . . . . . . . . 11 7.3 SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . . 16 7.4 Subscription Duration . . . . . . . . . . . . . . . . . . 16 7.5 NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . 17 7.6 Notifier processing of SUBSCRIBE requests . . . . . . . . 17 7.7 Notifier generation of NOTIFY requests . . . . . . . . . . 19 7.8 Subscriber processing of NOTIFY requests . . . . . . . . . 19 7.9 Handling of forked requests . . . . . . . . . . . . . . . 20 7.10 Rate of notifications . . . . . . . . . . . . . . . . . 20 7.11 State Agents . . . . . . . . . . . . . . . . . . . . . . 20 7.12 Examples . . . . . . . . . . . . . . . . . . . . . . . . 20 7.13 Use of URIs to Retrieve State . . . . . . . . . . . . . 21 7.13.1 Device URIs . . . . . . . . . . . . . . . . . . . . 22 7.13.2 User and Application URIs . . . . . . . . . . . . . 23 7.13.3 Local Network URIs . . . . . . . . . . . . . . . . . 24 8. Profile Delivery Framework Details . . . . . . . . . . . . . 24 8.1 Discovery of Subscription URI . . . . . . . . . . . . . . 24 8.1.1 Discovery of Local Network URI . . . . . . . . . . . . 25 8.1.2 Discovery of Device URI . . . . . . . . . . . . . . . 25 8.1.3 Discovery of User and Application URI . . . . . . . . 28 8.2 Enrollment with Profile Server . . . . . . . . . . . . . . 29 8.3 Notification of Profile Changes . . . . . . . . . . . . . 29 8.4 Retrieval of Profile Data . . . . . . . . . . . . . . . . 29 8.5 Upload of Profile Changes . . . . . . . . . . . . . . . . 30 8.6 Usage of XCAP with the Profile Package . . . . . . . . . . 30 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . 33 9.1 SIP Event Package . . . . . . . . . . . . . . . . . . . . 33 10. Security Considerations . . . . . . . . . . . . . . . . . . 33 10.1 Confidential Profile Content in NOTIFY Request . . . . . 34 10.2 Confidential Profile Content via Content Indirection . . 34 10.3 Integrity protection for non-confidential profiles . . . 36 Petrie Expires January 18, 2006 [Page 2] Internet-Draft SIP UA Profile Framework July 2005 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 36 12. Change History . . . . . . . . . . . . . . . . . . . . . . . 36 12.1 Changes from draft-ietf-sipping-config-framework-06.txt . . . . . . . 36 12.2 Changes from draft-ietf-sipping-config-framework-05.txt . . . . . . . 37 12.3 Changes from draft-ietf-sipping-config-framework-04.txt . . . . . . . 37 12.4 Changes from draft-ietf-sipping-config-framework-03.txt . . . . . . . 38 12.5 Changes from draft-ietf-sipping-config-framework-02.txt . . . . . . . 38 12.6 Changes from draft-ietf-sipping-config-framework-01.txt . . . . . . . 38 12.7 Changes from draft-ietf-sipping-config-framework-00.txt . . . . . . . 38 12.8 Changes from draft-petrie-sipping-config-framework-00.txt . . . . . . 39 12.9 Changes from draft-petrie-sip-config-framework-01.txt . 39 12.10 Changes from draft-petrie-sip-config-framework-00.txt . 39 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 40 13.1 Normative References . . . . . . . . . . . . . . . . . . 40 13.2 Informative References . . . . . . . . . . . . . . . . . 41 Author's Address . . . . . . . . . . . . . . . . . . . . . . 42 Intellectual Property and Copyright Statements . . . . . . . 43 Petrie Expires January 18, 2006 [Page 3] Internet-Draft SIP UA Profile Framework July 2005 1. Introduction Today all SIP (Session Initiation Protocol) [RFC3261] user agent implementers use proprietary means of delivering user, device, application and local network policy profiles to the user agent. The profile delivery framework defined in this document is intended to enable a first phase migration to a standard means of providing profiles to SIP user agents. It is expected that UA (User Agent) implementers will be able to use this framework as a means of delivering their existing proprietary data profiles (i.e. using their existing proprietary binary or text formats). This in itself is a tremendous advantage in that a SIP environment can use a single profile delivery server for profile data to user agents from multiple implementers. Follow-on standardization activities can: 1. define a standard profile content format framework (e.g. XML with namespaces [W3C.REC-xml-names11-20040204] or name-value pairs [RFC0822]). 2. specify the content (i.e. name the profile data parameters, xml schema, name spaces) of the data profiles. One of the objectives of the framework described in this document is to provide a start up experience similar to that of users of an analog telephone. When you plug in an analog telephone it just works (assuming the line is live and the switch has been provisioned). There is no end user configuration required to make analog phone work, at least in a basic sense. So the objective here is to be able to take a new SIP user agent out of the box, plug it in or install the software and have it get its profiles without human intervention other than security measures. This is necessary for cost effective deployment of large numbers of user agents. Another objective is to provide a scalable means for ongoing administration of profiles. Administrators and users are likely to want to make changes to profiles. Additional requirements for the framework defined in this document are described in: [I-D.ietf-sipping-ua-prof-framewk-reqs], [I-D.sinnreich-sipdev-req] 2. Requirements Terminology Keywords "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT" and "MAY" that appear in this document are to be interpreted as described in [RFC2119]. 3. Profile Delivery Framework Terminology Petrie Expires January 18, 2006 [Page 4] Internet-Draft SIP UA Profile Framework July 2005 profile - data set specific to a user, device, user's application or the local network. device - software or hardware appliance containing one or more SIP user agents. profile content server - The server that provides the content of the profiles using the protocol specified by the URI scheme. notifier - As defined in [RFC3265] the SIP user agent server which processes SUBSCRIBE requests for events and sends NOTIFY requests with profile data or URIs (Uniform Resource Identifiers) that point to the data. profile delivery server - The logical collection of the notifier and the server which provides the contents of the notification either directly in the NOTIFY requests or indirectly via profile URI(s). hotelling- when a user moves to a new user agent (i.e. that is not already provisioned to know the user's identity, credentials or profile data) and gives the user agent sufficient information to retrieve the user's profile(s). The user agent either permanently or temporarily makes the user's profiles effective on that user agent. roaming- when the user agent moves to a different local network 4. Overview The profile life cycle can be described by five functional steps. These steps are not necessarily discrete. However it is useful to describe these steps as logically distinct. These steps are named as follows: Discovery - discover a profile delivery server Enrollment - enroll with the profile delivery server Profile Retrieval - retrieve profile data Profile Change Notification - receive notification of profile changes Profile Change Upload - upload profile data changes back to the profile delivery server Discovery is the process by which a UA finds the address and port at which it enrolls with the profile delivery server. As there is no single discovery mechanism which will work in all network environments, a number of discovery mechanisms are defined with a prescribed order in which the UA tries them until one succeeds. The means of discovery is described in Section 8.1. Enrollment is the process by which a UA makes itself known to the profile delivery server. In enrolling, the UA provides identity information, requested profile type(s) and supported protocols for profile retrieval. It also subscribes to a mechanism for notification of profile changes. As a result of enrollment, the UA receives the data or the URI for each of the profiles that the Petrie Expires January 18, 2006 [Page 5] Internet-Draft SIP UA Profile Framework July 2005 profile delivery server is able to provide. Each profile type (set) requires a separate enrollment or SUBSCRIBE session. A profile type may represent one or more data sets (e.g. one profile data set for each of a user's applications). Enrollment which is performed by the device by constructing and sending a SUBSCRIBE request to profile delivery server for the event package described in Section 7. Profile Retrieval is the process of retrieving the content for each of the profiles the UA requested. The profiles are retrieved either directly or indirectly from the NOTIFY request body as describe in Section 7.5 and Section 8.4. Profile Change Notification is the process by which the profile delivery server notifies the UA that the content of one or more of the profiles has changed. If the content is provided indirectly the UA MAY retrieve the profile from the specified URI upon receipt of the change notification. Profile change notification is provided by the NOTIFY request for the event package as described in Section 7.8 and Section 8.3. Profile Change Upload is the process by which a UA or other entity (e.g. corporate directory or configuration management server) pushes a change to the profile data back up to the profile delivery server. This process is described in Section 8.5. This framework defines a new SIP event package [RFC3265] to solve enrollment and profile change notification steps. The event package in Section 7 defines everything but the mandatory content type. This makes this event package abstract until the content type is bound. The profile content type(s) will be defined outside the scope of this document. It is the author's belief that it would be a huge accomplishment if all SIP user agents used this framework for delivering their existing proprietary profiles. Even though this does not accomplish interoperability of profiles, it is a big first step in easing the administration of SIP user agents. The definition of standard profiles and data sets (see [I-D.petrie-sipping-profile- datasets] ) will enable interoperability as a subsequent step. The question arises as to why SIP should be used for the profile delivery framework. In this document SIP is used for only a small portion of the framework. Other existing protocols are more appropriate for transport of the profile contents (to and from the user agent) and are suggested in this document. The discovery step is simply a specified order and application of existing protocols (see Section 8.1). SIP is only needed for the enrollment (see Section 8.2) and change notification functionality (see Section 8.3) of the profile delivery framework. In many SIP environments (e.g. carrier/subscriber and multi-site enterprise) firewall, NAT (Network Petrie Expires January 18, 2006 [Page 6] Internet-Draft SIP UA Profile Framework July 2005 Address Translation) and IP addressing issues make it difficult to get messages between the profile delivery server and the user agent requiring the profiles. With SIP the users and devices already are assigned globally routable addresses. In addition the firewall and NAT problems are already presumably solved in the environments in which SIP user agents are to be used. The local network profile (see Section 6, Section 7.13.3 and Section 8.1.1) provides the means to get firewall and NAT traversal mechanism information to the device. Therefore SIP is the best solution for allowing the user agent to enroll with the profile delivery server, which may require traversal of multiple firewalls and NATs. For the same reason the notification of profile changes is best solved by SIP. It should be noted that this document is scoped to providing profiles for devices which contain one or more SIP user agents. This framework may be applied to non-SIP devices, however more general requirements for non-SIP devices are beyond the scope of this document. The content delivery server may be either in the public network or accessible through a private network. The user agents requiring profiles may be behind firewalls and NATs and many protocols, such as HTTP, may be used for profile content retrieval without special consideration in the firewalls and NATs (e.g. an HTTP client on the UA can typically pull content from a server outside the NAT/ firewall.). 5. Use Cases The following use case are intented to help give a understanding of how the profile delivery framework can be used. These use cases are not intended to be exhaustive in demonstrating all the capabilities or ways the framework can be applied. 5.1 Service Provider Use Case Scenario Bootstrapping with Digest Authentication The following describes a use case scenario for bootstrapping a new user agent, which has had no prior provisioned information, to the point of being functional with a SIP Service Provider's system. In this example scenario, the user has purchased a new SIP user agent. The user signs up for the service to obtain three pieces of information: a hostname, a user ID and a password. These three pieces of information may be one-time use, that become invalid after the one use. This scenario assumes that no association or mapping between the device and the user's account is created before the following steps: Petrie Expires January 18, 2006 [Page 7] Internet-Draft SIP UA Profile Framework July 2005 1. The user plugs the device in to provide power and network connectivity the first time (or installs the software in the case of a software user agent). The device subscribes to the local network to get the local network profile. However as the device is plugged into a residential LAN or router, there is no profile delivery server for the local network profile (see Section 8.1.1 and Section 7.13.3). The device assumes symmetric SIP signalling as there is not local network profie which may have provided other firewall or NAT traversal mechanism information. 2. The device prompts the user for the hostname to subscribe to for the device profile. The hostname was provided by the service provider and use as the host part of the SUBSCRIBE profile URI described in Section 7.13.1. Note: in a scenario where the system operator (e.g. enterprise) has control of the network, the hostname for the SUBSCRIBE can be discovered (see Section 8.1.2) to avoid the need for the user to enter the hostname. 3. The device creates a TLS connection for the SIP SUBSCRIBE request to the provided hostname. The device verifies the server's certificate. If the common name does not match the hostname or the certificate is not valid, the device warns the user and prompts whether to continue. 4. The profile delivery server receives the SUBSCRIBE request for the device profile and sends a NOTIFY with content indirection containing the HTTPS URI for the device profile (see Section 7.5). 5. The device receives the NOTIFY request with the device profile URI. The device prompts the user for the user ID and password provided by the service provider. The device does an HTTPS GET to retrieve the device profile (see Section 8.4 and Section 7.8). The profile delivery server challenges for Digest authentication. The device re-sends the HTTPS GET with Digest credentials using the user ID and password entered by the user. Note: for devices with only DTMF style input, the service provider may provide the host, user ID and password in octal format that can be entered requiring only digits. 6. The profile delivery server receives the HTTP GET request for the device profile along with the user ID and password for the specific user. At this point the profile delivery server has authenticated the user and can create an association between a specific device identified in the HTTPS URI and the user or user account (see Section 10.2). The profile delivery server provides the device profile which contains the on-going SUBSCRIBE request URIs for the device, user and application profiles along with credentials for retrieving the profiles. 7. The device receives the device profile from the HTTPS response, re-SUBSCRIBEs using the device profile URI provided in the profile. The device profile also may contain URIs for the default user's user and application profile SUBSCRIBE request Petrie Expires January 18, 2006 [Page 8] Internet-Draft SIP UA Profile Framework July 2005 URIs for the SIP event package defined in Section 7. The device uses these URIs to retrieve user and application profiles in a similar way to the device profile. After retriving these profiles the device is fully functional in the service provider's SIP service. 5.2 Service Provider Use Case Scenario Bootstrapping with Device Certificate The following describes another use case scenario where the device implementor provides a certificate for the device which authenticates the device ID. In this scenario, the user signs up for the SIP service with the service provider and provides the device ID (see Section 7.13.1 for more information on device ID) to the service provider prior to the following steps, so that the service provider has an association or mapping between the device ID and the user account ahead of time. The service provide gives the user a hostname to be entered on the device. 1. Step 1-3 occur the same as in the prior use case described in Section 5.1. 2. The device receives the NOTIFY request with the device profile URI. The device does an HTTPS GET to retrieve the device profile (see Section 8.4 and Section 7.8). 3. The profile delivery server requests the device certficate in the TLS connection used for the HTTPS GET. The device has a certificate which has a SIP URI in the Subject Alternative Name field that contains the device ID. The device certificate is signed and provided by the implementor for the purpose of authenticating the device ID in the initial bootstrapping process only. The profile delivery server validates the device ID and encrypts the device profile using the public key in the device's certificate as described in Section 10.2 4. The device receives the encrypted device profile from the HTTPS response, decrypts the profile using it private key. The process continues in a similar way to step 6 in the above use case. The device profile contains a more perminent device certificate and private key or Digest authentication credentials which is used for on-going device ID authentication. 6. Data Model A conscious separation of device, user, application and local network profiles is made in this document. This is useful to provide features such as hotelling (described above) as well as securing or restricting user agent functionality. By maintaining this separation, a user may walk up to someone else's user agent and direct that user agent to get the new user's profile data. In doing Petrie Expires January 18, 2006 [Page 9] Internet-Draft SIP UA Profile Framework July 2005 so the user agent can replace the previous user's profile data while still keeping the device's and the local network's profile data which may be necessary for core functionality and communication described in this document. The local network profiles are relevant to a visiting device which gets plugged in to a foreign network. The concept of the local network providing profile data is useful to provide roaming (described above) as well as local policy data that may constrain the user or device behavior relative to the local network. For example media types and codecs may be constrained to reflect the network's capabilities. The separation of these profiles also enables the separation of the management of the profiles. The user profile may be managed by a profile delivery server operated by the user's ISP. The device profile may be delivered from a profile delivery server operated by the user's employer. The application profile(s) may be delivered from the user's ASP (Application Service Provider). The local network profile may delivered by a WLAN (Wireless LAN) hotspot service provider. Some interesting services and mobility applications are enabled with this separation of profiles. A very high level data model is implied here with the separation of these four profile types. Each profile type instance requires a separate subscription to retrieve the profile. A loose hierarchy exists mostly for the purpose of bootstrapping and discovery or formation of the profile URIs. No other meaning is implied by this hierarchy. However the profile format and data sets to be defined outside this document may define additional meaning to this hierarchy. In the bootstrapping scenario, a device straight out of the box (software or hardware) does not know anything about its user or local network. The one thing that is does know is it's instance id. So the hierarchy of the profiles exists as follows. The local network profile is subscribed to and retrieved based upon a URI formed from the local network domain. The local network profile is subscribed to first as it may contain information on how to communicate to the Internet or primary network from the local network (e.g. HTTP proxy, SIP firewall or NAT traversal information). The device instance id is used to form the user id part of the URI for subscribing to the device and local network profiles. The device profile may contain a default user AOR (Address of Record) for that device. The default user AOR may then be used to retrieve the user profile. Applications to be used on the device may be defined in the device and user profiles. The user's AOR is also used to retrieve any application profiles for that user. Petrie Expires January 18, 2006 [Page 10] Internet-Draft SIP UA Profile Framework July 2005 7. Profile Change Event Notification Package This section defines a new SIP event package [RFC3265]. The purpose of this event package is to send to subscribers notification of content changes to the profile(s) of interest and to provide the location of the profile(s) via content indirection [I-D.ietf-sip- content-indirect-mech] or directly in the body of the NOTIFY. Frequently the profiles delivered to the user agent are much larger (e.g. several KB or even several MB) than the MTU of the network. These larger profiles will cause larger than normal SIP messages and consequently higher impact on the SIP servers and infrastructure. To avoid the higher impact and load on the SIP infrastructure, content indirection SHOULD be used if the profile is large enough to cause packet fragmentation over the transport protocol. The presence of the MIME type for content indirection [I-D.ietf-sip-content-indirect- mech] in the Accept header indicates that the user agent supports content indirection and that the profile delivery server SHOULD use content indirection. Similarly the content type for the differential notification of profile changes [I-D.ietf-simple-xcap-package] may be used in the Accept header to express support for receiving profile change deltas. The MIME types or formats of profiles to be delivered via this framework are to be defined in the documents that define the profile contents. These profile MIME types specified in the Accept header along with the profile types specified in the Event header parameter "profile-type" MAY be used to specify which profiles get delivered either directly or indirectly in the NOTIFY requests. As this event package does not specify the mandatory content type, this package is abstract. The profile definition documents will specify the mandatory content type to make a concrete event package. 7.1 Event Package Name The name of this package is "ua-profile". This value appears in the Event header field present in SUBSCRIBE and NOTIFY requests for this package as defined in [RFC3265]. 7.2 Event Package Parameters This package defines the following new parameters for the event header: "profile-type", "vendor", "model", "version", "effective-by", "document", "auid", "network-user". The "effective-by" parameter is for use in NOTIFY requests only. The "effective-by" parameter is ignored if it appears in a SUBSCRIBE request. The other parameters are for use in the SUBSCRIBE request and are ignored if they appear in NOTIFY requests. Petrie Expires January 18, 2006 [Page 11] Internet-Draft SIP UA Profile Framework July 2005 The "profile-type" parameter is used to indicate the token name of the profile type the user agent wishes to obtain data or URIs for and to be notified of subsequent changes. Using a token in this parameter allows the URI semantics for retrieving the profiles to be opaque to the subscribing user agent. All it needs to know is the token value for this parameter. This document defines four logical types of profiles and their token names. The contents or format of the profiles is outside the scope of this document. The four types of profiles defined here are "device", "user", "application" and "local-network". Specifying "device" type profile(s) indicates the desire for the profile data (URI when content indirection is used) and change notification of the contents of the profile that is specific to the device or user agent. Specifying "user" type profile indicates the desire for the profile data (URI when content indirection is used) and change notification of the profile content for the user. Specifying "application" type profile indicates the desire for the profile data (URI when content indirection is used) and change notification of the profile content for the user's applications. Specifying "local-network" type profile indicates the desire for profile data (URI when content indirection is used) specific to the local network. The device, user, application or local network is identified in the URI of the SUBSCRIBE request. A separate SUBSCRIBE dialog is used for each profile type. The profile type associated with the dialog can then be used to infer which profile type changed and is contained in the NOTIFY or content indirection URI. The Accept header of the SUBSCRIBE request MUST include the MIME types for all profile content types for which the subscribing user agent wishes to retrieve profiles or receive change notifications. In the following ABNF, EQUAL and token are defined in [RFC3261]. Profile-type = "profile-type" EQUAL profile-value profile-value = profile-types / token profile-types = "device" / "user" / "application" / "local-network" The "device", "user", "application" or "local-network" token in the profile-type parameter may represent a class or set of profile properties. As standards are defined for specific profile contents related to the user, device or local network, it may be desirable to define additional tokens for the profile-type parameter. Also additional content types may be defined along with the profile formats that can be used in the Accept header of the SUBSCRIBE to filter or indicate what data sets of the profile are desired. The rational for the separation of user, device, application and local network type profiles is provided in Section 4. It should be Petrie Expires January 18, 2006 [Page 12] Internet-Draft SIP UA Profile Framework July 2005 noted that any of the types may result in zero or more profiles or URIs being provided in the NOTIFY request. As discussed, a default user may be assigned to a device. The default user's AOR, if defined in the device profile, may in turn be used as the URI to SUBSCRIBE to the "user" and "application" profile types. The data provided in the four types of profiles may overlap. As an example the codecs that a user prefers to use, the codecs that the device supports (and the enterprise or device owner wishes to use), the codecs that the local network can support (and the network operator wishes to allow) all may overlap in how they are specified in the three corresponding profiles. This policy for merging the constraints across the multiple profile types can only unambiguously be defined in the context of the profile syntax and semantics. This is out of scope for this document. The "vendor", "model" and "version" parameter values are tokens specified by the implementer of the user agent. These parameters MUST be provided in the SUBSCRIBE request for all profile types. The implementer SHOULD use their DNS domain name (e.g. example.com) as the value of the "vendor" parameter so that it is known to be unique. These parameters are useful to the profile delivery server to affect the profiles provided. In some scenarios it is desirable to provide different profiles based upon these parameters. For example feature property X in a profile may work differently on two versions of user agent. This gives the profile delivery server the ability to compensate for or take advantage of the differences. In the following ABNF, EQUAL and quoted-string are defined in [RFC3261]. Vendor = "vendor" EQUAL quoted-string Model = "model" EQUAL quoted-string Version = "version" EQUAL quoted-string The "network-user" parameter SHOULD be set when subscribing for device and local network profiles if the user's AOR is known. When the profile-type is "device" or "local-network", the SUBSCRIBE URI addresses the device or local network profile delivery server. It by design cannot indicate the user's identity. The "network-user" parameter is used to indicate the user's AOR. The SUBSCRIBE server SHOULD authenticate the subscriber to verify the AOR in the "network- user" parameter if the profile provided is specific to the AOR. If the value of the "profile-type" parameter is not "device" or "local- network", the "network-user" parameter has no defined meaning and is ignored. If the "network-user" parameter is provided in the SUBSCRIBE request, it MUST be present in the NOTIFY request as well. In the following ABNF, name-addr, addr-spec are defined in [RFC3261]. Network-User = "network-user" EQUAL name-addr / addr-spec Petrie Expires January 18, 2006 [Page 13] Internet-Draft SIP UA Profile Framework July 2005 When the profile-type is "device", the user agent SHOULD set the "network-user" parameter to the user's AOR if it is known. This is an indication to the profile delivery server to set or change the association of the default user with the device indicated in the SUBSCRIBE URI. If the profile delivery server implements and allows this policy of setting the default user with a device, the user agent can utilize this mechanism to allow a user to login and make the user agent and user association permanent. In the case where the profile-type is "local-network", the user agent SHOULD set the "network-user" parameter if the user's AOR is known. If the user has special privileges beyond that of an anonymous user in the local network, the "network-user" parameter identifies the user to the local network. The value of this parameter is the user's address of record. The "effective-by" parameter in the Event header of the NOTIFY request specifies the maximum number of seconds before the user agent must attempt to make the new profile effective. The "effective-by" parameter MAY be provided in the NOTIFY request for any of the profile types. A value of 0 (zero) indicates that the subscribing user agent must attempt to make the profiles effective immediately (despite possible service interruptions). This gives the profile delivery server the power to control when the profile is effective. This may be important to resolve an emergency problem or disable a user agent immediately. The "effective-by" parameter is ignored in all messages other than the NOTIFY request. In the following ABNF, EQUAL and DIGIT are defined in [RFC3261]. Effective-By = "effective-by" EQUAL 1*DIGIT The "document" parameter is used to specify a relative URI for a specific profile document that the user agent wishes to retrieve and for which it wishes to receive change notification. This is useful for profile content like XCAP [I-D.ietf-simple-xcap] where there is a well defined URI schema and the user agent knows the specific content that it wants. This provides a filtering mechanism to restrict the content to be retrieved and for which change notification is to be received. (The size of the content is important in limited bandwidth environments.) The "document" parameter value syntax is a quoted string. The values for the "document" parameter are defined as part of the profile data format, which is out of scope for this document. To use the "document" parameter, the profile data format, must also define a URL path schema. For more details on the use of this package and the "document" parameter with XCAP see Section 8.6. The "document" parameter MAY be set in SUBSCRIBE requests for any of the profile types. It is ignored in all other messages. In the following ABNF EQUAL and quoted-string is defined in [RFC3261]. Petrie Expires January 18, 2006 [Page 14] Internet-Draft SIP UA Profile Framework July 2005 Document = "document" EQUAL quoted-string The "auid" parameter MAY be set when the "profile-type" parameter value is "application". The "auid" indicates that the user agent wishes to retrieve the profile data or URI and change notification for the application profile data for the specific application indicated in the value of the "auid" parameter. Like the "document" parameter, the "auid" parameter provides a filtering mechanism on the profile content. The "auid" parameter value is a quoted string. The values for the "auid" parameter are defined as part of the profile data format to be used with XCAP (see [I-D.ietf-simple-xcap] ), which is out of scope for this document. The "auid" parameter has meaning only in SUBSCRIBE requests when the "profile-type" Event header parameter is set to "application". It is an error to set both the "document" and "auid" parameters in a SUBSCRIBE request. The "auid" parameter is ignored in all other messages. AUID = "auid" EQUAL quoted-string SUBSCRIBE request Event header examples: Event: ua-profile;profile-type=device; vendor="vendor.example.com";model="Z100";version="1.2.3" Event: ua-profile;profile-type="user"; document="user-aor/"; vendor="premier";model="trs8000";version="5.5" NOTIFY request Event header examples: Event: ua-profile;effective-by=0 Event: ua-profile;effective-by=3600 The following table shows the use of Event header parameters in SUBSCRIBE requests for the four profile types: Petrie Expires January 18, 2006 [Page 15] Internet-Draft SIP UA Profile Framework July 2005 profile-type || device | user | application | local-network =========================================================== vendor || m | m | m | m model || m | m | m | m version || m | m | m | m network-user || | | | s document || o | o | o | o auid || | | o | effective-by || | | | m - manditory s - SHOULD be provided o - optional Non-specified means that the parameter has no meaning and should be ignored. The following table shows the use of Event header parameters in NOTIFY requests for the four profile types: profile-type || device | user | application | local-network =========================================================== vendor || | | | model || | | | version || | | | network-user || | | | s document || o/m | o/m | o/m | o/m auid || | | o/m | effective-by || o | o | o | o o/m - manditory if provided in the SUBSCRIBE request 7.3 SUBSCRIBE Bodies This package defines no new use of the SUBSCRIBE request body. Future documents may specify a filter-like mechanism using etags to minimize the delivery or notification of profiles where the user agent already has a current version. 7.4 Subscription Duration As the presence (or lack of) a device or user agent is not very time critical to the functionality of the profile delivery server, it is recommended that default subscription duration be 86400 seconds (one day). A one-time fetch of a profile can be accomplished by setting the Expires parameter to 0 as defined in [RFC3265] resulting in a single NOTIFY with no change notification. Petrie Expires January 18, 2006 [Page 16] Internet-Draft SIP UA Profile Framework July 2005 7.5 NOTIFY Bodies The size of profile content is likely to be hundreds to several thousand of bytes in size. For this reason if the Accept header of the SUBSCRIBE included the MIME type message/external-body indicating support for content indirection the profile delivery server SHOULD use content indirection [I-D.ietf-sip-content-indirect-mech] in the NOTIFY body for providing the profiles. When delivering profiles via content indirection the profile delivery server MUST include the Content-ID MIME header described in [I-D.ietf-sip-content-indirect-mech] for each profile URI. This is to avoid unnecessary download of the profiles. Some user agents are not able to make a profile effective without rebooting or restarting. Rebooting is something to be avoided on a user agent performing services such as telephony. In this way the Content-ID allows the user agent to avoid unnecessary interruption of service as well. The Content-Type MUST be specified for each URI. For minimal interoperability, the profile delivery server MUST support the "http:" and "https:" URI schemes for content indirection. Other URI schemes MAY also be provided in the content indirection. However the security considerations are define for content indirection using HTTP and HTTPS. Other protocols MAY be supported for content indirection, but are out of scope of this document. Initially user agent implementers may use a proprietary content type for the profiles retrieved from the URI(s). This is a good first step towards easing the management of user agents. Standard profile contents, content type and formats will need to be defined for true interoperability of profile delivery. The specification of the content is out of the scope of this document. The URI scheme [RFC2396] used in content indirection may be dictated by the profile content that is required. It is expected that FTP [RFC0959], HTTP [RFC2616], HTTPS [RFC2818], LDAP [RFC3377], XCAP [I-D.ietf-simple-xcap] and other URI schemes could be used by this package and framework if the subscribing user agent and profile delivery server both support the same scheme. The negotiation of the URI scheme is described in the following sections. 7.6 Notifier processing of SUBSCRIBE requests The general rules for processing SUBSCRIBE requests [RFC3265] apply to this package. If content indirection is used for delivering the profiles, the notifier does not need to authenticate the subscription as the profile content is not transported in the SUBSCRIBE or NOTIFY transaction messages. With content indirection only URIs are transported in the NOTIFY request which may be secured using the Petrie Expires January 18, 2006 [Page 17] Internet-Draft SIP UA Profile Framework July 2005 techniques in Section 10. If content indirection is not used, the subscribe server SHOULD reject SUBSCRIBE requests from conections that are not over TLS and SHOULD challenge the SUBSCRIBE request with SIP Digest authentication. The subscriber MUST support the "http:" or "https:" URI scheme for content indirection. If the subscriber wishes to use a URI scheme other than "http:", the subscriber must use the "schemes" Contact header field parameter to indicate the URI scheme as defined in [I-D.ietf-sip-content-indirect-mech]. For example the subscriber may request that content indirection use the "ldaps:" URI scheme by including "ldaps" in the "scheme" Contact header parameter of the SUBSCRIBE request. If the subscriber does not specify the URI scheme, the notifier may use either "http:" or "https:". The profile generation behavior of the profile delivery server is left to the implementer. The profile delivery server may be as simple as a SIP SUBSCRIBE UAS and NOTIFY UAC front end to a simple HTTP server delivering static files that are hand edited. At the other extreme the profile delivery server can be part of a configuration management system that integrates with a corporate directory and IT system or carrier operations support systems, where the profiles are automatically generated. The design of this framework intentionally provides the flexibility of implementation from simple/cheap to complex/expensive. If the user or device is not known to the profile delivery server, the implementer MAY accept the subscription or reject it. It is recommended that the implementer accept the subscription. It is useful for the profile delivery server to maintain the subscription for unprovisioned users or devices as an administrator may add the user or device to the system after the initial subscription, defining the profile contents. This allows the profile delivery server to immediately send a NOTIFY request with the profile URIs. If the profile delivery server does not accept the subscription from an unknown user or device, the administer or user must manually provoke the user agent to re-subscribe. This may be difficult if the user agent and administrator are at different locations. A user agent can provide hotelling by collecting a user's AOR and credentials needed to SUBSCRIBE and retrieve the user's profiles. Hotelling functionality is achieved by subscribing to the user's AOR and specifying the "user" profile type. This same mechanism can also be used to secure a user agent, requiring a non-mobile user to login to enable functionality beyond the default user's restricted functionality. When the Event header "profile-type" is "device" and the user agent has provided the user's AOR in the "network-user" parameter, the Petrie Expires January 18, 2006 [Page 18] Internet-Draft SIP UA Profile Framework July 2005 profile delivery server MAY set or change the default user associated with the device indicated in the SUBSCRIBE URI. This is an implementation or policy decision. The profile delivery server SHOULD authenticate the user for the SUBSCRIBE request before changing the default user associated with the device. 7.7 Notifier generation of NOTIFY requests As in [RFC3265], the profile delivery server MUST always send a NOTIFY request upon accepting a subscription. If the device or user is unknown to the profile delivery server and it chooses to accept the subscription, the implementer has two choices. A NOTIFY MAY be sent with no body or content indirection containing the profile URI(s). Alternatively a NOTIFY MAY be sent with a body or content indirection containing URI(s) pointing to a default data set. The data sets provided may allow for only limited functionality of the user agent (e.g. for a user agent with telephony capabilities, to enable calls to help desk and emergency services.). This is an implementation and business policy decision for the profile delivery server. If the URI in the SUBSCRIBE request is a known identity and is provisioned with the requested profile type (i.e. as specified in the profile-type parameter of the Event header), the profile delivery server SHOULD send a NOTIFY with profile data or content indirection (if the content indirection mime type was included in the Accept header) containing the URI for the profile. To protect the integrety of the profile data or indirect content profile data URIs, the notifier SHOULD send the NOTIFY request on the same TLS connection as the SUBSCRIBE request came in on if TLS was used. The profile delivery server may specify when the new profiles must be made effective by the user agent. The profile delivery server MAY specify a maximum time in seconds (zero or more), in the "effective-by" event header parameter, by which the user agent is required to make the new profiles effective for all dialogs. 7.8 Subscriber processing of NOTIFY requests The user agent subscribing to this event package MUST adhere to the NOTIFY request processing behavior specified in [RFC3265]. The user agent MUST attempt to make the profiles effective within the time in seconds given in the "effective-by" Event header parameter if present in the NOTIFY request (see Section 7.7). By default the user agent makes the profiles effective as soon as it thinks that it is non- obtrusive to do so (e.g. when there are no active calls). Profile changes SHOULD affect behavior on all new dialogs which are created after the notification, but may not be able to affect existing Petrie Expires January 18, 2006 [Page 19] Internet-Draft SIP UA Profile Framework July 2005 dialogs. The user agent SHOULD use one of the techniques specified in Section 10 to securely retrieve the profiles. If the subscriber included the MIME type message/external-body for content indirection in the SUBSCRIBE request Accept header, the subscriber MUST support the http: or https: URI schemes for content indirection. If the subscriber indicated alternative URI schemes for content indirection it MUST also indicate support for http: or https:. The subscriber should still be prepared to use http: or https: as the profile delivery server may not support the alternative URI schemes. 7.9 Handling of forked requests This event package allows the creation of only one dialog as a result of an initial SUBSCRIBE request. The techniques to achieve this are described in section 4.4.9 of [RFC3265]. 7.10 Rate of notifications It is anticipated that the rate of change for user and device profiles will be very infrequent (i.e. days or weeks apart). For this reason no throttling or minimum period between NOTIFY requests is specified for this package. 7.11 State Agents State agents are not applicable to this event package. 7.12 Examples Example SUBSCRIBE and NOTIFY request using content indirection: Petrie Expires January 18, 2006 [Page 20] Internet-Draft SIP UA Profile Framework July 2005 SUBSCRIBE sip:MAC%3aFF00000036C5@acme.example.com SIP/2.0 Event: ua-profile;profile-type=device;vendor="vendor.example.com"; model="Z100";version="1.2.3" From: sip:MAC%3aFF00000036C5@acme.example.com;tag=1234 To: sip:MAC%3aFF00000036C5@acme.example.com;tag=abcd Call-ID: 3573853342923422@10.1.1.44 CSeq: 2131 SUBSCRIBE Contact: sip:MAC%3aFF00000036C5@10.1.1.44 Via: SIP/2.0/TCP 10.1.1.41; branch=z9hG4bK6d6d35b6e2a203104d97211a3d18f57a Accept: message/external-body, application/z100-device-profile Content-Length: 0 NOTIFY sip:MAC%3aFF00000036C5@10.1.1.44 SIP/2.0 Event: ua-profile;effective-by=3600 From: sip:MAC%3aFF00000036C5@acme.example.com;tag=abcd To: sip:MAC%3aFF00000036C5@acme.example.com;tag=1234 Call-ID: 3573853342923422@10.1.1.44 CSeq: 321 NOTIFY Via: SIP/2.0/UDP 192.168.0.3; branch=z9hG4bK1e3effada91dc37fd5a0c95cbf6767d1 MIME-Version: 1.0 Content-Type: multipart/mixed; boundary=boundary42 Content-Length: ... --boundary42 Content-Type: message/external-body; access-type="URL"; expiration="Mon, 24 June 2002 09:00:00 GMT"; URL="http://www.example.com/devices/ff00000036c5"; size=1234 Content-Type: application/z100-device-profile Content-ID: <39EHF78SA@example.com> --boundary42-- 7.13 Use of URIs to Retrieve State The URI for the SUBSCRIBE request is formed differently depending upon which profile type the subscription is for. This allows the different profile types to be potentially managed by different profile delivery servers (perhaps even operated by different entities). Petrie Expires January 18, 2006 [Page 21] Internet-Draft SIP UA Profile Framework July 2005 7.13.1 Device URIs The URI for the "device" type profile (device URI) is based upon the identity of the device. The device URI MUST be unique across all devices and implementations. If an instance id is used as the user part of the device URI, it SHOULD remain the same for the lifetime of the user agent. The device URI is used to identify which profile is associated with a specific instance of a user agent. If the user agent changed its device URI, the profile delivery server would not know the association between the profile and the device. This would also make it difficult for the profile delivery server to track user agents under profile management. The profile delivery server may decide to provide the same device profile to all devices of the same vendor, model and version. However this is a implementation choice of the profile delivery server. The subscribing device has no way of knowing whether the profiles for each device are different. For this reason the device must always use a unique id in the device SUBSCRIBE request URI. As an example the device profile for similar devices may differ with properties such as the default user. This is how the bootstrapping mechanism works as described in Section 8.1.3. The URI for the device type profile MUST use a unique identifier as the user portion of the URI. The host and port portion of the URI is set to that of the domain or address of the profile delivery server which manages that user agent. A means of discovering the host and port portion is discussed in Section 8.1. There is an administration aspect of the unique identifier, that makes it desirable for the id to be obtainable or predictable prior to installation of the device (hard or soft). Also from a human factors perspective, ids that are easily distinguished and communicated will make the administrators job a little easier. The MAC address or UUID SHOULD be used for constructing a unique identifier to be used in the user portion of the device URI. If the identifier is a MAC address, it MUST be formatted as the letters "MAC:" followed by a 12 digit hexadecimal representation of the MAC address. The address can not include ":", whitespace, or other formatting. The MAC address of the device may be used if there will always be no more than one user agent using that MAC address over time (e.g. a dedicated telephone appliance). The MAC address may not be used if more than one user agent instance exists using the same MAC address (e.g. multiple instances of a softphone may run on a general purpose computing device). The advantage of the MAC address is that many vendors put bar codes on the device with the actual MAC address on it. A bar code scanner is a convenient Petrie Expires January 18, 2006 [Page 22] Internet-Draft SIP UA Profile Framework July 2005 means of collecting the instance id for input and provisioning on the profile delivery server. If the MAC address is used, it is recommended that the MAC address is rendered in all upper case with no punctuation for consistency across implementations. A prefix of "MAC:" should be added to the MAC address to form a proper URN [RFC2141]. For example a device managed by sipuaconfig.example.com using its MAC address to form the device URI might look like: sip:MAC%3a00DF1E004CD0@sipuaconfig.example.com. UHEX = DIGIT / %x41-46 ;uppercase A-F MAC = %x4d.41.43 ; MAC in caps mac-ident = MAC ":" 12UHEX When the MAC address is not used in the device URI, UUID SHOULD be used. For devices where there is no MAC address or the MAC address is not unique to an instance of a user agent (e.g. multiple softphones on a computer or a gateway with multiple logical user agents) it is recommended that a UUID is used as the user portion of the device URI. The same approach to defining a user agent instance ID as [I-D.ietf-sip-gruu] should be used. When constructing the instance id the implementer should also consider that a human may need to manually enter the instance id to provision the device in the profile delivery server (e.g. longer strings are more error prone in data entry). When the URN is used as the user part of URI, it MUST be URL escaped. The ":" is not a legal character (without being escaped) in the user part of a name-addr. For example the instance ID: urn:uuid:f81d4fae-7ced-11d0-a765-00a0c91e6bf6 would be escaped to look as follows in a URI: sip:urn%3auuid%3af81d4fae-7ced-11d0-a765-00a0c91e6bf6@example.com. Soft user agents are likely to need to use this approach due to the multi-user nature of general purpose computers. The software installer program might generate the uuid as part of the install process so that it remains persistent for the installation. It may also be desirable that any upgrades of the software maintain the unique id. However these are all implementation choices. 7.13.2 User and Application URIs The URI for the "user" and "application" type profiles is based upon the identity of the user. The user's address of record (AOR) is used as the URI in the SUBSCRIBE request. A new user agent or device may not know the user's AOR. The user's AOR may be obtained as part of a default user property in the device profile. Alternatively the user Petrie Expires January 18, 2006 [Page 23] Internet-Draft SIP UA Profile Framework July 2005 agent may prompt the user for an AOR and credentials to be used to authenticate the request. This can provide a login and/or hotelling feature on the user agent. The user agent may be pre-provisioned with the user's AOR or provided as information on a SIM or flash key. These are only examples not an exhaustive list of sources for the user AOR. 7.13.3 Local Network URIs The URI for the "local-network" type profile is based upon the identity of the local network. When subscribing to the local network profile, the user part of the URI SHOULD be the same device ID used as the user part of the device profile SUBSCRIBE request URI defined in Section 7.13.1. The host and port part of the URI is the local network name/domain. The discovery of the local network name or domain is discussed in Section 8.1. The user agent may provide the user's AOR as the value to the "network-user" event header parameter. This is useful if the user has privileges in the local network beyond those of the default user. When "network-user" is provided the profile delivery server SHOULD authenticate the user before providing the profile if additional privileges are granted. Example URI: sip:MAC%3a00DF1E004CD0@example.com The local network profile SUBSCRIBE request URI uses the device ID in the user part of the local network request URI so that every device in the network has a unique and constant request URI. Even though every device may get the same or similar local network profiles, the uniqueness of the URI provides an important capability. Having unique URIs allows the management of the local network to track user agents present in the network and consequently also manage resources such as bandwidth and port allocation. 8. Profile Delivery Framework Details The following describes how different functional steps of the profile delivery framework work. Also described here is how the event package defined in this document provides the enrollment and notification functions within the framework. 8.1 Discovery of Subscription URI The discovery approach varies depending upon which profile type URI is to be discovered. The order of discovery is important in the bootstrapping situation as the user agent may not have any information provisioned. The local network profile should be discovered first as it may contain key information such as how to traverse a NAT/firewall to get to outside services (e.g. the user's Petrie Expires January 18, 2006 [Page 24] Internet-Draft SIP UA Profile Framework July 2005 profile delivery server). The device profile URI should be discovered next. The device profile may contain the default user's AOR or firmware/software information that should be updated first before proceeding with the discovery process. The user and application profile subscription URIs should be discovered last. The URIs are formed differently for each of the profile types. This is to support the delegation of the profile management to potentially four different entities. However all four profile types may be provided by the same entity. As the user agent has no way of knowing whether the profiles are provide by one or more different profile delivery servers ahead of time, it must subscribe to all four profile types in separate SUBSCRIBE requests to get the profiles. 8.1.1 Discovery of Local Network URI The "discovered" host for the "local-network" profile subscription URI is the local IP network domain for the user agent, either provisioned as part of the device's static network configuration or discovered via DHCP. The local network profile subscription URI SHOULD not be remembered if the user agent moves from one local network to another other. The user agent should perform the local network discovery to construct the network profile subscription request URI every time it starts up or network connectivity is regained. For example: The user agent requested and received the local domain name via DHCP: airport.example.net. If the device ID is: MAC:00DF1E004CD0, the local network profile SUBSCRIBE request URI would look like: sip:MAC%3a00DF1E004CD0@airport.example.net. The user agent should send this request using the normal SIP locating mechanisms defined in [RFC3263]. The Event header would look like the following if the user agent decided to provide sip:alice@example.com as the user's AOR. (Alice may have a prior arrangement with the local network operator giving her special privileges.): Event: ua-profile;profile-type=local-network; network-user="sip:alice@example.com" 8.1.2 Discovery of Device URI The discovery function is needed to bootstrap user agents to the point of knowing where to enroll with the profile delivery server. Section 7.13.1 describes how to form the user part of the device profile SUBSCRIBE request URI used for enrollment. However the bootstrapping problem for the user agent (out of the box) is what to use for the host and port in the device URI. Due to the wide Petrie Expires January 18, 2006 [Page 25] Internet-Draft SIP UA Profile Framework July 2005 variation of environments in which the enrolling user agent may reside (e.g. behind residential router, enterprise LAN, WLAN hotspot, ISP, dialup modem) and the limited control that the administrator of the profile delivery server (e.g. enterprise, service provider) may have over that environment, no single discovery mechanism works everywhere. Therefore a number of mechanisms should be tried in the specified order: SIP DHCP option [RFC3361], SIP DNS SRV [RFC3263], DNS A record and manual. The user agent may be pre-provisioned with the host and port (e.g. service providers may pre-provision a device before sending it to a subscriber, provide a SIM or flash key, etc.) in which case this discovery mechanism is not needed. Before performing the discovery steps, the user agent should provide a means to skip the discovery stage and manually enter the device URI host and port. In addition the user agent should allow the user to accept or reject the discovered host and port, in case an alternate to the discovered host and port are desired. 1. The first discovery mechanism that should be tried to construct the device SUBSCRIBE request URI, as described in Section 7.13.1, is to use the host and port of the outbound proxy discovered by the SIP DHCP option as described in [RFC3361]. If the SIP DHCP option is not provided in the DHCP response; or no SIP response is received for the SUBSCRIBE request; or a SIP failure response other than for authorization is received for the SUBSCRIBE request to the ua-profile event, the next discovery mechanism should be tried. For example: Consider a dedicated hardware device with a single user agent having the MAC address: abc123efd456. The user agent sends a DHCP request including the request for the DHCP option for SIP: 120 (see [RFC3361]). If the DHCP response includes an answer for option 120, then the DNS name or IP address included is used in the host part of the device URI. For this example let's assume: example.com. The device URI would look like: sip:MAC%3aABC123EFD456@example.com. The user agent should send this request using the normal SIP locating mechanisms defined in [RFC3263]. If the response fails then, the next discovery mechanism is tried. 2. The local IP network domain for the user agent, either configured or discovered via DHCP, should be used with the technique in [RFC3263] to obtain a host and port to use in the SUBSCRIBE URI. If no SIP response or a SIP failure response other than for authorization is received for the SUBSCRIBE request to the ua- profile event, the next discovery mechanism should be tried. Petrie Expires January 18, 2006 [Page 26] Internet-Draft SIP UA Profile Framework July 2005 For example: The user agent requested and received the local domain name (option 15) in the DHCP response: boston.example.com. The device URI would look like: sip:MAC%3aABC123EFD456@boston.example.com. The user agent should send this request using the normal SIP locating mechanisms defined in [RFC3263]. If the response fails then, the next discovery mechanism is tried. 3. The fully qualified host name constructed by concatenating "sipuaconfig" and the local IP network domain (as provided via DHCP or provisioned) should be tried next using the technique in [RFC3263] to obtain a host and port to use in the SUBSCRIBE URI. If no SIP response or a SIP failure response other than for authorization is received for the SUBSCRIBE request to the ua- profile event, the next discovery mechanism should be tried. For example: The user agent requested and received the local domain name via DHCP as in the above example: boston.example.com. The device URI would look like: sip:MAC%3aABC123EFD456@sipuaconfig.boston.example.com. The user agent should send this request using the normal SIP locating mechanisms defined in [RFC3263]. If the response fails then, the next discovery mechanism is tried. 4. If all other discovery techniques fail, a manual means for the user to enter the host and port used to construct the SUBSCRIBE request URI MUST be provided by the user agent. Two approaches to the manual discovery process are suggested. In the first approach using SIP, the user agent provides a means for entering the subscription host and port information for the request URI along with the user id and password to be used for authentication of the SUBSCRIBE request. With this approach the user agent begins with the enrollment process followed by the change notification and profile retrieve steps. An alternative to the manual discovery using SIP, is to start with the retrieve process. The user agent provides a means of entering a HTTPS URI along with the user id and password to be used for authentication of the retrieval of the profile. The retrieved device profile may contain the properties for the SUBSCRIBE request URI and credentials to enroll and get change notification of profile changes. This approach bootstraps the process in a different step in the cycle, but uses the same profile framework. When the device starts with retrieval of the profile via HTTPS (instead of a SIP SUBSCRIBE to the event package), the device MUST provide the Event header in the HTTPS request using the same format as described for the Petrie Expires January 18, 2006 [Page 27] Internet-Draft SIP UA Profile Framework July 2005 SUBSCRIBE request (see Section 7.2) . The Event header is necessary to determine which profile is requested as well as for providing specific information about the device. Once a user agent has successfully discovered, enrolled and received a NOTIFY response with profile data or URI(s), the user agent should cache (i.e. store persistantly) the device profile SUBSCRIBE request URI (rather than reconstructing it as described in the discovery process every time the device is restarted) to avoid having to rediscover the profile delivery server again in the future. Caching of the device URI is necessary when the user agent is likely to move to different local network domains as the local network may not be the provider for the device's profile. The user agent should not cache the device URI until it receives a NOTIFY with profile data or URI(s). The reason for this is that a profile delivery server may send 202 responses to SUBSCRIBE requests and NOTIFY responses to unknown user agent (see Section 7.6) with no profile data or URIs. Until the profile delivery server has sent a NOTIFY request with profile data or URI(s), it has not agreed to provide profiles. To illustrate why the user agent should not cache the device profile SUBSCRIBE URI until profile data or URI(s) are provided in the NOTIFY, consider the following example: a user agent running on a laptop plugged into a visited LAN in which a foreign profile delivery server is discovered. The profile delivery server never provides profile URIs in the NOTIFY request as it is not provisioned to accept the user agent. The user then takes the laptop to their enterprise LAN. If the user agent cached the SUBSCRIBE URI from the visited LAN (which did not provide profiles), when subsequently placed in the enterprise LAN which is provisioned to provide profiles to the user agent, the user agent would not attempt to discover the profile delivery server. 8.1.3 Discovery of User and Application URI The user's AOR may be preprovisioned or provided via SIM or flash key, etc. The device profile may define a default user and AOR. If provided in the device profile and a preprovisioned user AOR is not provided, the default user's AOR is used to subscribe to the "user" and "application" profiles. If not provided through the above two approaches, the AOR to be used for the "user" and "application" subscription URI, is "discovered" manually by prompting the user. The URI obtained in the discovery steps described above for the "user" and "application" profile subscriptions is stored persistantly in the device until explicitly reset or updated by the user or profile. Petrie Expires January 18, 2006 [Page 28] Internet-Draft SIP UA Profile Framework July 2005 8.2 Enrollment with Profile Server Enrollment is accomplished by subscribing to the event package described in Section 7. The enrollment process is useful to the profile delivery server as it makes the server aware of user agents to which it may deliver profiles (those user agents the profile delivery server is provisioned to provide profiles to; those present to which the server may provide profiles in the future; and those that the server can automatically provide default profiles). It is an implementation choice and business policy as to whether the profile delivery server provides profiles to user agents that it is not explicitly provisioned to do so. However the profile delivery server SHOULD accept (with 2xx response) SUBSCRIBE requests from any user agent as explained in Section 7.5. 8.3 Notification of Profile Changes The NOTIFY request in the ua-profile event package serves two purposes. First it provides the user agent with a means to obtain the profile data directly or via URI(s) for desired profiles without requiring the end user to manually enter them. It also provides the means for the profile delivery server to notify the user agent that the content of the profiles has changed and should be made effective. Optionally the differential changes may be obtained by notification by including the content-type: "application/xcap-diff+xml" defined in [I-D.ietf-simple-xcap-package] in the Accept header of the SUBSCRIBE request. 8.4 Retrieval of Profile Data The user agent retrieves its needed profile(s) directly or via the URI(s) provided in the NOTIFY request as specified in Section 7.5. The profile delivery server SHOULD secure the content of the profiles using one of the techniques described in Section 10. The user agent SHOULD make the new profiles effective in the timeframe described in Section 7.2. The contents of the profiles SHOULD be cached (i.e. stored persistently) by the user agent. The cache should be used if the user agent is unable to successfully SUBSCRIBE or receive the NOTIFY providing the most recent profile. The cached profile should be replaced each time a profile is received in a NOTIFY or retrieved via content indirection. This it to avoid the situation where the content delivery server being not available, leaves the user agent non-functional. The user agent should verify that it has the latest profile content using the "hash" parameter defined in [I-D.ietf-sip- content-indirect-mech]. Petrie Expires January 18, 2006 [Page 29] Internet-Draft SIP UA Profile Framework July 2005 8.5 Upload of Profile Changes The user agent or other service MAY push changes up to the profile delivery server using the technique appropriate to the profile's URL scheme (e.g. HTTP PUT method, FTP put command). The technique for pushing incremental or atomic changes MUST be described by the specific profile data framework. A means for pushing changes up into the profile delivery server for XCAP is defined in [I-D.ietf-simple- xcap]. 8.6 Usage of XCAP with the Profile Package This framework allows for the usage of several different protocols for the retrieval of profiles. One protocol which is suitable is XCAP [I-D.ietf-simple-xcap], which allows for HTTP URIs to represent XML documents, elements and attributes. XCAP defines a specific hierarchy for how documents are organized. As a result, it is necessary to discuss how that organization relates to the rough data model presented here. When a user or device enrolls with a SUBSCRIBE request, the request URI will contain identifying information for that user or device. This identity is mapped to an XCAP User ID (XUID) based on an implementation specific mapping. The "profile-type" along with the "auid" Event header parameters specify the specific XCAP application usage. In particular, when the Event header parameter "profile-type" is "application", the "auid" MAY be included to contain the XCAP Application Unique ID (AUID) [I-D.ietf-simple-xcap]. When the "profile-type" is "application", but the "auid" parameter is absent, this specifies that the user wishes to SUBSCRIBE to all documents for all application usages associated with the user in the request-uri. This provides a convenient way for a single subscription to be used to obtain all application data. The XCAP root is determined by a local mapping. When the "profile-type" is "device", or "user" or "local-network", this maps to an AUID and document selector for representing device, user and local-network data, respectively. The mapping is a matter of local policy. This allows different providers to use different XCAP application usages and document schemas for representing these profiles, without having to configure the device with the specific AUID which is being used. Furthermore, when the "document" attribute is present, it identifies a specific document that is being requested. The "auid" SHOULD NOT be present if the "document" is also present. The "document" Petrie Expires January 18, 2006 [Page 30] Internet-Draft SIP UA Profile Framework July 2005 attribute specifies a relative path reference. The path is constucted from a set of path segments (e.g. directories) using the "/" separator. For XCAP the relative document path is constructed using the following steps:" 1. Its first path segment is either "global", specifying global data, or "user", specifying user data for the user in the request URI. 2. If the prior path segment is "user", the next path segment identifies the the user's home directory. That is the next path segment is the user's directory name. The user's directory name is appended onto the "document" path with the "/" separator. If the prior path segment is "global" nothing is appended to the document path for this step. 3. When the "profile-type" is "application", the next path segment to append (i.e. after "global" or the user's home directory segment) MAY indicate the XCAP Application Unique ID (AUID) if the user agent wishes to subscribe to a specific application profile. 4. If the AUID was added to the document path in the prior step, additional path segments may be added according to the specific schema of the profile and the query mechanism provided in [I-D.ietf-simple-xcap]. For example, consider a phone with an instance ID of urn:uuid:00000000-0000-0000-0000-0003968cf920. To obtain its device profile, it would generate a SUBSCRIBE that contains the following Request-Line and Event header: (Note that line folding of the Request-URI is illegal in SIP. The Request URI is shown broken across the first 3-lines here only due to formatting limitations of IETF documents. The Event header is shown continued across a second line for the same reason.) SUBSCRIBE sip:urn%3auuid%3a00000000-0000-0000-0000-0003968cf920@example.com SIP/2.0 Event: ua-profile;profile-type=device;Vendor="vendor2"; Model="1";Version="2.2.2" If the profile data is stored in an XCAP server, the server would map the "device" profile to an application usage and document selector based on local policy. The user ID that might be used in the case of a device profile could be the device ID which is identified in the user part of the SUBSCRIBE URI. The XCAP server may use a root directory of: http://xcap.example.com/root. Local policy may provide a mapping for the AUID "vendor2-device-data" based upon the "vendor" parameter and a document called "index" within the user directory, Petrie Expires January 18, 2006 [Page 31] Internet-Draft SIP UA Profile Framework July 2005 the corresponding HTTP URI for the document might be: (Note that this URL is only one line; it is split across three lines due to formatting limitations of IETF documents.) http://xcap.example.com/root/users/ urn%3auuid%3a00000000-0000-0000-0000-0003968cf920/ vendor2-device-data/index and indeed, if a content indirection is returned in a NOTIFY, the URL would equal this. That user profile might specify the user identity (as a SIP AOR) and their application-usages. From that, the device can enroll to learn about its application data. To learn about all of the data: SUBSCRIBE sip:alice@example.com SIP/2.0 Event: ua-profile;profile-type=application;Vendor="vendor2"; Model="1";Version="2.2.2" The server would map the request URI to an XUI (user-aor, for example) and the xcap root based on local policy. If there are two AUIDs, "resource-lists" [I-D.ietf-simple-xcap-list-usage] and "rls- services" [I-D.ietf-simple-xcap-list-usage], this would result in a subscription to all documents within: http://xcap.example.com/root/users/user-aor/rls-services http://xcap.example.com/root/users/user-aor/resource-lists The user would not be subscribed to the global data for these two application usages, since that data is not important for users. However, the user/device could be made aware that it needs to subscribe to a specific document. In that case, its subscribe would look like: SUBSCRIBE sip:user-aor@example.com SIP/2.0 Event: ua-profile;profile-type=application;auid="resource-lists"; Vendor="vendor2";Model="1";Version="2.2.2" this would result in a subscription to the single global document for resource-lists. In some cases, these subscriptions are to a multiplicity of documents. In that case, the notification format will need to be one Petrie Expires January 18, 2006 [Page 32] Internet-Draft SIP UA Profile Framework July 2005 which can indicate what document has changed. This includes content indirection, but also the xcap diff format [I-D.ietf-simple-xcap- package]. 9. IANA Considerations There are several IANA considerations associated with this specification. 9.1 SIP Event Package This specification registers a new event package as defined in [RFC3265]. The following information required for this registration: Package Name: ua-profile Package or Template-Package: This is a package Published Document: RFC XXXX (Note to RFC Editor: Please fill in XXXX with the RFC number of this specification). Person to Contact: Daniel Petrie dan.ietf AT SIPez DOT com New event header parameters: profile-type, vendor, model, version, effective-by, document, auid, network-user 10. Security Considerations Profiles may contain sensitive data such as user credentials and personal information. The protection of this data depends upon how the data is delivered. Some profiles may be safe to deliver without the need to protect the content. For example in some environments the local network profile may contain the list of codecs that are acceptable for use in the network and information on NAT traversal such as a STUN server to use. As the information in this example local network profile does not contain passwords or sensitive information it may be acceptable to provide it without authentication or confidentiality (encryption). We refer to these as non- confidential profiles. Non-confidential profiles require message integrity and profile server authentication, as described in Section 10.3. However any profiles that contain personal information, passwords or credentials (confidential profiles) require mutual authentication, confidentiality, and message integrity, and must follow the guidance provided in the next two subsections. Profile specifications that define schemas MUST identify if they contain confidential data to indicate which of the security approaches describer here should be used. The profile data is delivered in either the NOTIFY request or via the URI scheme indicated in the content indirection in the NOTIFY request. The security approach is different for these two delivery mechanisms. Petrie Expires January 18, 2006 [Page 33] Internet-Draft SIP UA Profile Framework July 2005 Subscribers implementing this specification MUST implement either HTTP or HTTPS. Subscribers also MUST implement the hash verification scheme described in SIP content indirection [I-D.ietf-sip-content- indirect-mech]. SIP profile delivery servers MUST implement both HTTP and HTTPS, and SHOULD implement a SIP Authentication Service as described in the SIP Identity mechanism [I-D.ietf-sip-identity]. All SIP entities are already required to implement SIP Digest authentication [RFC3261]. 10.1 Confidential Profile Content in NOTIFY Request When the profile data is delivered directly in the NOTIFY request, the SUBSCRIBE request MUST be authenticated using the SIP Digest authentication mechanism. As the profile content is delivered in the resulting NOTIFY request to the subscription, authenticating the SUBSCRIBE is the only way to prevent unauthorized access to the profile data. To provide message integrity and confidentiality over the profile data, a direct TLS connection MUST be established for the SUBSCRIBE request. The device SHOULD authenticate the server via the TLS connection, which also provides a means of verifying that a direct TLS connection was used (e.g. The device may prompt the user to verify the Common Name in the server's certificate.). The server may challenge the device for its certificate, when establishing the TLS connection, to obtain the public to S/MIME encode the NOTIFY request body containing the profile data. Because the device verified that it has a direct TLS connection by verifying the server's certificate and the server verified the identity of the device using Digest Authentication, the server can assume the certficate provided by the device is authenticated. The use of S/MIME in the NOTIFY request does not relieve the need to authenticate the SUBSCRIBE request using SIP Digest authentication. In this scenario S/MIME only provides message integrity and confidentiality of the content of the profile. If S/MIME is not used for the profile data in the NOTIFY request, the notifier MUST use the same direct TLS connection established by device for the SUBSCRIBE request. In this scenario the use of user specific ID and secret in the Digest Authentication can be used to establish an association between user ID and the device ID provide in the device profile SUBSCRIBE request. 10.2 Confidential Profile Content via Content Indirection When the profile data is delivered via content indirection, authentication, integrity, confidentiality are all provided in the profile indirection retrieval scheme. When content indirection is used, the SUBSCRIBE request does not need to be authenticated. There is a TLS certificate approach and a Digest Authentication approach which may be used to provide the required security. The profile Petrie Expires January 18, 2006 [Page 34] Internet-Draft SIP UA Profile Framework July 2005 delivery server MUST support both of these methods. The device MUST support the Digest Authentication method to provide minimal interoperablity. For the TLS certificate approach, the device requests the profile using HTTPS. To provide authentication, the server challenges the device for its certificate. The server obtains the user part of the SIP URI in the Subject Alternative Name field of the device's certificate. The user part of the SIP URI in the device's certificate is used as the device ID to authenticate if the device is authorized to retieive the specified profile. The device certificates chain of authorities MUST also be verified. This approach for providing security requires that the device ID and associated user are provisioned to the content indirection retreival. For the Digest Authentication approach, HTTPS SHOULD be used to provide confidentiality of the profile data. HTTP Digest Authentication [RFC2617] MUST be used to authenticate and authorize the device to retrieve the profile. The shared secret used in the Digest Authentication is provided through out of band means to the device or user of the device. The same credentials used for SIP Digest authentication (e.g. authenication of SIP SUBSCRIBE and REGISTER requests) are used in the HTTPS request. Other URI schemes may be used, but are not defined in this document. A non-replayable authentication mechanism such as Digest authentication MUST be used for the content indirection URI scheme which provides the profile data (e.g. LDAP, HTTP and HTTPS all support Digest authentication). URI schemes which provide no authentication or only clear-text authentication SHOULD NOT be used for profile delivery as they are vulnerable to replay attacks (e.g. TFTP does not provide authentication). Without a suitable authentication mechanism, the content indirection profile delivery URI scheme is susceptible to replay attacks. Even if the profile is symmetrically encrypted, if it can be retrieved through a replay attack, the encrypted profile can be used for offline attacks to crack the encryption key. The profile delivery scheme MUST use channel security such as TLS (e.g. HTTPS) to protect the content from being snooped in transport to the user agent. Mutual authentication using the client and server certificates MAY be used to verify the authenticity of the user or device identity and the profile delivery server identity. The user agent SHOULD provide a mechanism for the user to approve the SUBSCRIBE server identity or provision the acceptable server identity through out of band means. Petrie Expires January 18, 2006 [Page 35] Internet-Draft SIP UA Profile Framework July 2005 10.3 Integrity protection for non-confidential profiles Even for non-confidential profiles, the subscriber MUST verify the authenticity of the profile delivery server, and MUST verify that the integrity of the profile data and content indirection URI, if one is provided. To meet these requirements in the SIP messaging the NOTIFY request MUST use a SIP Identity header [I-D.ietf-sip-identity], or S/MIME. If content is provided via redirection, the content indirection "hash" parameter MUST be included unless the profile data is delivered via a protocol which natively provides authentication and message integrity, such as HTTP or LDAP protected by TLS. The content retrieved via the content indirection URI MUST be integrity checked using the "hash" parameter. For example, Alice subscribes to the local domain profile for paris.example.com. She receives the following NOTIFY request which uses content indirection, including a "hash" parameter. Alice uses the Identity header from the NOTIFY to verify that the request came from paris.example.com and that the body was not modified. Then she fetches the content at the provided URI and verifies that the hash she calculates from the profile matches the hash provided in the SIP signaling. 11. Acknowledgements Many thanks to those who contributed and commented on the many iterations of this document. Detailed input was provided by Jonathan Rosenberg from Cisco, Henning Schulzrinne from Columbia University, Cullen Jennings from Cisco, Rohan Mahy from Airespace, Rich Schaaf from Pingtel, Volker Hilt from Bell Labs, Adam Roach of Estacado Systems, Hisham Khartabil from Telio, Henry Sinnreich from MCI, Martin Dolly from AT&T Labs, John Elwell from Siemens, Elliot Eichen and Robert Liao from Verizon, Dale Worley from Pingtel. 12. Change History [[RFC Editor: Please remove this entire section upon publication as an RFC.]] 12.1 Changes from draft-ietf-sipping-config-framework-06.txt Restructured the introduction and overview section to be more consistent with other Internet-Drafts. Added additional clarifcation for the Digest Authentication and Certificate based authentication cases in the security section. Added two use case scenarios with cross referencing to better illustrate how the framework works. Added better cross referencing in the overview section to help readers find where Petrie Expires January 18, 2006 [Page 36] Internet-Draft SIP UA Profile Framework July 2005 concepts and functionality is defined in the document. Clarified the section on the use of XCAP. Changed the Event parameter "App-Id" to "auid". Made "auid" mutually exclusive to "document". "auid" is now only used with XCAP. Local network subscription URI changed to @ (was anonymous@). Having a different request URI for each device allows the network management to track user agents and potentially manage bandwidth, port allocation, etc. Changed event package name from sip-profile to ua-profile per discussion on the list and last IETF meeting. Changed "local" profile type token to "local-network" per discussion on the list and last IETF meeting. Simplified "Vendor", "Model", "Version" event header parameters to allow only quoted string values (previously allowed token as well). Clarified use of the term cache. Added references for ABNF constructs. Numerous editorial changes. Thanks Dale! 12.2 Changes from draft-ietf-sipping-config-framework-05.txt Made HTTP and HTTPS profile transport schemes mandatory in the profile delivery server. The subscribing device must implement HTTP or HTTPS as the profile transport scheme. Rewrote the security considerations section. Divided references into Normative and Informative. Minor edits throughout. 12.3 Changes from draft-ietf-sipping-config-framework-04.txt Clarified usage of instance-id Specify which event header parameters are mandatory or optional and in which messages. Included complete list of event header parameters in parameter overview and IANA sections. Removed TFTP reference as protocol for profile transport. Added examples for discovery. Added ABNF for all event header parameters. Changed profile-name parameter back to profile-type. This was changed to profile-name in 02 when the parameter could contain either a token or a path. Now that the path is contained in the separate parameter: "document", profile-type make more sense as the parameter name. Fixed some statements that should have and should not have been normative. Petrie Expires January 18, 2006 [Page 37] Internet-Draft SIP UA Profile Framework July 2005 Added the ability for the user agent to request that the default user associated with the device be set/changed using the "network- user" parameter. A bunch of editorial nits and fixes. 12.4 Changes from draft-ietf-sipping-config-framework-03.txt Incorporated changes to better support the requirements for the use of this event package with XCAP and SIMPLE so that we can have one package (i.e. simple-xcap-package now defines a content type not a package). Added an additional profile type: "application". Added document and app-id Event header parameters in support of the application profile. Define a loose high level data model or relationship between the four profile types. Tried to edit and fix the confusing and ambiguous sections related to URI formation and discovery for the different profile types. Better describe the importance of uniqueness for the instance id which is used in the user part of the device URI. 12.5 Changes from draft-ietf-sipping-config-framework-02.txt Added the concept of the local network as a source of profile data. There are now three separate logical sources for profile data: user, device and local network. Each of these requires a separate subscription to obtain. 12.6 Changes from draft-ietf-sipping-config-framework-01.txt Changed the name of the profile-type event parameter to profile-name. Also allow the profile-name parameter to be either a token or an explicit URI. Allow content indirection to be optional. Clarified the use of the Accept header to indicate how the profile is to be delivered. Added some content to the Iana section. 12.7 Changes from draft-ietf-sipping-config-framework-00.txt This version of the document was entirely restructured and re-written from the previous version as it had been micro edited too much. All of the aspects of defining the event package are now organized in one section and is believed to be complete and up to date with [RFC3265]. The URI used to subscribe to the event package is now either the user or device address or record. Petrie Expires January 18, 2006 [Page 38] Internet-Draft SIP UA Profile Framework July 2005 The user agent information (vendor, model, MAC and serial number) are now provided as event header parameters. Added a mechanism to force profile changes to be make effective by the user agent in a specified maximum period of time. Changed the name of the event package from sip-config to ua-profile Three high level security approaches are now specified. 12.8 Changes from draft-petrie-sipping-config-framework-00.txt Changed name to reflect SIPPING work group item Synchronized with changes to SIP DHCP [RFC3361], SIP [RFC3261] and [RFC3263], SIP Events [RFC3265] and content indirection [I-D.ietf- sip-content-indirect-mech] Moved the device identity parameters from the From field parameters to User-Agent header parameters. Many thanks to Rich Schaaf of Pingtel, Cullen Jennings of Cisco and Adam Roach of Estacado Systems for the great comments and input. 12.9 Changes from draft-petrie-sip-config-framework-01.txt Changed the name as this belongs in the SIPPING work group. Minor edits 12.10 Changes from draft-petrie-sip-config-framework-00.txt Split the enrollment into a single SUBSCRIBE dialog for each profile. The 00 draft sent a single SUBSCRIBE listing all of the desired. These have been split so that each enrollment can be routed differently. As there is a concept of device specific and user specific profiles, these may also be managed on separate servers. For instance in a roaming situation the device might get its profile data from a local server which knows the LAN specific profile data. At the same time the user specific profiles might come from the user's home environment profile delivery server. Removed the Config-Expires header as it is largely superfluous with the SUBSCRIBE Expires header. Eliminated some of the complexity in the discovery mechanism. Suggest caching information discovered about a profile delivery Petrie Expires January 18, 2006 [Page 39] Internet-Draft SIP UA Profile Framework July 2005 server to avoid an avalanche problem when a whole building full of devices powers up. Added the User-Profile From header field parameter so that the device can request a user specific profile for a user that is different from the device's default user. 13. References 13.1 Normative References [I-D.ietf-sip-content-indirect-mech] Burger, E., "A Mechanism for Content Indirection in Session Initiation Protocol (SIP) Messages", draft-ietf-sip-content-indirect-mech-05 (work in progress), October 2004. [I-D.ietf-sip-identity] Peterson, J. and C. Jennings, "Enhancements for Authenticated Identity Management in the Session Initiation Protocol (SIP)", draft-ietf-sip-identity-05 (work in progress), May 2005. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. [RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC 2246, January 1999. [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., Leach, P., Luotonen, A., and L. Stewart, "HTTP Authentication: Basic and Digest Access Authentication", RFC 2617, June 1999. [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. Petrie Expires January 18, 2006 [Page 40] Internet-Draft SIP UA Profile Framework July 2005 [RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation Protocol (SIP): Locating SIP Servers", RFC 3263, June 2002. [RFC3265] Roach, A., "Session Initiation Protocol (SIP)-Specific Event Notification", RFC 3265, June 2002. [RFC3361] Schulzrinne, H., "Dynamic Host Configuration Protocol (DHCP-for-IPv4) Option for Session Initiation Protocol (SIP) Servers", RFC 3361, August 2002. 13.2 Informative References [I-D.ietf-simple-xcap] Rosenberg, J., "The Extensible Markup Language (XML) Configuration Access Protocol (XCAP)", draft-ietf-simple-xcap-07 (work in progress), June 2005. [I-D.ietf-simple-xcap-list-usage] Rosenberg, J., "Extensible Markup Language (XML) Formats for Representing Resource Lists", draft-ietf-simple-xcap-list-usage-05 (work in progress), February 2005. [I-D.ietf-simple-xcap-package] Rosenberg, J., "An Extensible Markup Language (XML) Document Format for Indicating Changes in XML Configuration Access Protocol (XCAP) Resources", draft-ietf-simple-xcap-package-03 (work in progress), January 2005. [I-D.ietf-sip-gruu] Rosenberg, J., "Obtaining and Using Globally Routable User Agent (UA) URIs (GRUU) in the Session Initiation Protocol (SIP)", draft-ietf-sip-gruu-04 (work in progress), July 2005. [I-D.ietf-sipping-ua-prof-framewk-reqs] Petrie, D. and C. Jennings, "Requirements for SIP User Agent Profile Delivery Framework", draft-ietf-sipping-ua-prof-framewk-reqs-00 (work in progress), March 2003. [I-D.petrie-sipping-profile-datasets] Petrie, D., "A Schema for Session Initiation Protocol User Agent Profile Data Sets", draft-petrie-sipping-profile-datasets-00 (work in progress), July 2004. Petrie Expires January 18, 2006 [Page 41] Internet-Draft SIP UA Profile Framework July 2005 [I-D.sinnreich-sipdev-req] Sinnreich, H., "SIP Telephony Device Requirements and Configuration", draft-sinnreich-sipdev-req-07 (work in progress), June 2005. [RFC0822] Crocker, D., "Standard for the format of ARPA Internet text messages", STD 11, RFC 822, August 1982. [RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol", STD 9, RFC 959, October 1985. [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [RFC2141] Moats, R., "URN Syntax", RFC 2141, May 1997. [RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998. [RFC3377] Hodges, J. and R. Morgan, "Lightweight Directory Access Protocol (v3): Technical Specification", RFC 3377, September 2002. [W3C.REC-xml-names11-20040204] Tobin, R., Hollander, D., Layman, A., and T. Bray, "Namespaces in XML 1.1", W3C REC REC-xml-names11-20040204, February 2004. Author's Address Daniel Petrie SIPez LLC. 34 Robbins Rd Arlington, MA 02476 US Phone: "+1 617 273 4000 Email: dan.ietf AT SIPez DOT com URI: http://www.SIPez.com/ Petrie Expires January 18, 2006 [Page 42] Internet-Draft SIP UA Profile Framework July 2005 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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