--- 1/draft-ietf-sipping-config-framework-17.txt 2010-10-08 01:12:16.000000000 +0200 +++ 2/draft-ietf-sipping-config-framework-18.txt 2010-10-08 01:12:16.000000000 +0200 @@ -1,58 +1,53 @@ SIPPING D. Petrie Internet-Draft SIPez LLC. Intended status: Standards Track S. Channabasappa, Ed. -Expires: August 20, 2010 CableLabs - February 16, 2010 +Expires: April 10, 2011 CableLabs + October 7, 2010 A Framework for Session Initiation Protocol User Agent Profile Delivery - draft-ietf-sipping-config-framework-17 + draft-ietf-sipping-config-framework-18 Abstract This document specifies a framework to enable configuration of Session Initiation Protocol (SIP) User Agents in SIP deployments. The framework provides a means to deliver profile data that User Agents need to be functional, automatically and with minimal or no User and Administrative intervention. The framework describes how SIP User Agents can discover sources, request profiles and receive notifications related to profile modifications. As part of this framework, a new SIP event package is defined for notification of profile changes. The framework provides minimal data retrieval options to ensure interoperability. The framework does not include specification of the profile data within its scope. Status of this Memo - This Internet-Draft is submitted to IETF in full conformance with the + This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering - Task Force (IETF), its areas, and its working groups. Note that - other groups may also distribute working documents as Internet- - Drafts. + Task Force (IETF). Note that other groups may also distribute + working documents as Internet-Drafts. The list of current Internet- + Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - 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 August 20, 2010. + This Internet-Draft will expire on April 10, 2011. Copyright Notice + Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of @@ -50,74 +45,74 @@ document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as - described in the BSD License. + described in the Simplified BSD License. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 + 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1. Reference Model . . . . . . . . . . . . . . . . . . . . . 7 3.2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 8 3.3. Profile Types . . . . . . . . . . . . . . . . . . . . . . 11 - 3.4. Profile delivery stages . . . . . . . . . . . . . . . . . 12 + 3.4. Profile delivery stages . . . . . . . . . . . . . . . . . 11 + 3.5. Supported Device Types . . . . . . . . . . . . . . . . . . 12 4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - 4.1. Simple Deployment Scenario . . . . . . . . . . . . . . . . 12 + 4.1. Simple Deployment Scenario . . . . . . . . . . . . . . . . 13 4.2. Devices supporting multiple users from different Service Providers . . . . . . . . . . . . . . . . . . . . 14 5. Profile Delivery Framework . . . . . . . . . . . . . . . . . . 16 5.1. Profile delivery stages . . . . . . . . . . . . . . . . . 16 5.1.1. Profile Enrollment . . . . . . . . . . . . . . . . . . 17 5.1.2. Content Retrieval . . . . . . . . . . . . . . . . . . 19 5.1.3. Change Notification . . . . . . . . . . . . . . . . . 19 5.1.4. Enrollment Data and Caching . . . . . . . . . . . . . 20 - 5.2. Securing Profile Delivery . . . . . . . . . . . . . . . . 23 + 5.2. Securing Profile Delivery . . . . . . . . . . . . . . . . 24 5.2.1. Securing Profile Enrollment . . . . . . . . . . . . . 24 5.2.2. Securing Content Retrieval . . . . . . . . . . . . . . 25 5.2.3. Securing Change Notification . . . . . . . . . . . . . 26 5.3. Additional Considerations . . . . . . . . . . . . . . . . 26 5.3.1. Bootstrapping Identities and Credentials . . . . . . . 26 5.3.2. Profile Enrollment Request Attempt . . . . . . . . . . 28 - 5.3.3. Device Types . . . . . . . . . . . . . . . . . . . . . 32 - 5.3.4. Profile Data . . . . . . . . . . . . . . . . . . . . . 32 - 5.3.5. Profile Data Frameworks . . . . . . . . . . . . . . . 33 - 5.3.6. Additional Profile Types . . . . . . . . . . . . . . . 34 - 5.3.7. Deployment considerations . . . . . . . . . . . . . . 34 - 5.4. Support for NATs . . . . . . . . . . . . . . . . . . . . . 35 + 5.3.3. Profile Data . . . . . . . . . . . . . . . . . . . . . 32 + 5.3.4. Profile Data Frameworks . . . . . . . . . . . . . . . 33 + 5.3.5. Additional Profile Types . . . . . . . . . . . . . . . 33 + 5.3.6. Deployment considerations . . . . . . . . . . . . . . 34 + 5.4. Support for NATs . . . . . . . . . . . . . . . . . . . . . 34 6. Event Package Definition . . . . . . . . . . . . . . . . . . . 35 6.1. Event Package Name . . . . . . . . . . . . . . . . . . . . 35 6.2. Event Package Parameters . . . . . . . . . . . . . . . . . 35 6.3. SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . . 38 - 6.4. Subscription Duration . . . . . . . . . . . . . . . . . . 39 + 6.4. Subscription Duration . . . . . . . . . . . . . . . . . . 38 6.5. NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . 39 6.6. Notifier Processing of SUBSCRIBE Requests . . . . . . . . 39 - 6.7. Notifier Generation of NOTIFY Requests . . . . . . . . . . 40 + 6.7. Notifier Generation of NOTIFY Requests . . . . . . . . . . 39 6.8. Subscriber Processing of NOTIFY Requests . . . . . . . . . 40 6.9. Handling of Forked Requests . . . . . . . . . . . . . . . 41 6.10. Rate of Notifications . . . . . . . . . . . . . . . . . . 41 6.11. State Agents . . . . . . . . . . . . . . . . . . . . . . . 41 7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 7.1. Example 1: Device requesting profile . . . . . . . . . . . 41 7.2. Example 2: Device obtaining change notification . . . . . 44 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 48 8.1. SIP Event Package . . . . . . . . . . . . . . . . . . . . 48 8.2. Registry of SIP configuration profile types . . . . . . . 48 @@ -143,46 +138,47 @@ intervention. Many deployments of SIP User Agents require dynamic configuration and cannot rely on pre-configuration. This framework provides a standard means of providing dynamic configuration which simplifies deployments containing SIP User Agents from multiple vendors. This framework also addresses change notifications when profiles change. However, the framework does not define the content or format of the profile, leaving that to future standardization activities. - This document is organized as follows. Section 3 provides a high- + This document is organized as follows. The normative requirements + are contained in Section 5 (framework operations) and Section 6 (the + event package definition). The rest of the document provides + introductory and supporting explanations. Section 3 provides a high- level overview of the abstract components, profiles, and the profile delivery stages. Section 4 provides some motivating use cases. - Section 5 provides details of the framework operation and - requirements. Section 6 provides a concise event package definition. Section 7 follows with illustrative examples of the framework in use. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. This document also reuses the SIP terminology defined in [RFC3261] and [RFC3265], and specifies the usage of the following terms. Device: software or hardware entity containing one or more SIP user - agents. It may also contain entities such as a DHCP client. + agents. It may also contain applications such as a DHCP client. Device Provider: the entity responsible for managing a given device. Local Network Provider: the entity that controls the local network to which a given device is connected. SIP Service Provider: the entity providing SIP services to users. - This can refer to private enterprises or public entities. + This can refer to private or public enterprises. Profile: configuration data set specific to an entity (e.g., user, device, local network or other). Profile Type: a particular category of Profile data (e.g., User, Device, Local Network or other). Profile Delivery Server (PDS): the source of a Profile, it is the logical collection of the Profile Notification Component (PNC) and the Profile Content Component(PCC). @@ -220,21 +216,21 @@ messages (SUBSCRIBE and NOTIFY; [RFC3265]) and traditional file retrieval protocols, such as HTTP [RFC2616], to discover, monitor, and retrieve configuration profiles. The framework defines three types of profiles (local-network, device, and user) in order to separate aspects of the configuration which may be independently managed by different administrative domains. The initial SUBSCRIBE message for each profile allows the UA to describe itself (both its implementation and the identity requesting the profile), while requesting access to a profile by type, without prior knowledge of the profile name or location. Discovery mechanisms are specified to - help the UA form the subscription URI (the Request-URI for the SIP + help the UA form the Subscription URI (the Request-URI for the SIP SUBSCRIBE). The SIP UAS handling these subscriptions is the Profile Delivery Server (PDS). When the PDS accepts a subscription, it sends a NOTIFY to the device. The initial NOTIFY from the PDS for each profile may contain profile data or a reference to the location of the profile, to be retrieved using HTTP or similar file retrieval protocols. By maintaining a subscription to each profile, the UA will receive additional NOTIFY messages if the profile is later changed. These may contain a new profile, a reference to a new profile, or a description of profile changes, depending on the Content-Type [RFC3261] in use by the subscription. The framework @@ -394,32 +390,23 @@ the Local Network Provider. Device Profile: contains configuration data related to a specific device, provided by the Device Provider. User Profile: contains configuration data related to a specific User, as required to reflect that user's preferences and the particular services subscribed to. It is provided by the SIP Service Provider. - Additional profile types may also be specified. - - PDSs and devices will implement all the three profile types. A - device that has not been configured otherwise will try to obtain all - the three profile types, in the order specified by this framework. A - device being bootstrapped SHOULD request the device profile type (see - Section 5.3.1 for more information). The device can be configured - with a different behavior via profile data previously obtained by the - device, or by using other means such as pre-configuration or manual - configuration. The data models associated with each profile type are - out of scope for this document. Follow-on standardization activities - are expected to specify such data models. + Additional profile types may also be specified by future work within + the IETF. The data models associated with each profile type are out + of scope for this document. 3.4. Profile delivery stages The framework specified in this document requires a device to explicitly request profiles. It also requires one or more PDSs which provide the profile data. The processes that lead a device to obtain profile data, and any subsequent changes, can be explained in three stages, termed the profile delivery stages. Profile Enrollment: the process by which a device requests, and if @@ -431,20 +418,36 @@ Profile Content Retrieval: the process by which a device retrieves profile contents, if the profile enrollment resulted in content indirection information. Profile Change Notification: the process by which a device is notified of any changes to an enrolled profile. This may provide the device with modified profile data or content indirection information. +3.5. Supported Device Types + + The examples in this framework tend to associate devices with + entities that are accessible to end-users. However, this is not + necessarily the only type of device that can utilize the specified + Framework. Devices can be entities such as SIP Phones or soft + clients, with or without user interfaces (that allow for device + Configuration), entities in the network that do not directly + communicate with any users (e.g., gateways, media servers, etc) or + network infrastructure elements (e.g., SIP servers). The framework + is extensible for use with such device types. However, it is to be + noted that some of these other device types (e.g., network elements) + may also be configurable using other mechanisms. The use of this + framework in conjunction with other mechanisms (specified outside of + this document), is out of scope. + 4. Use Cases This section provides a small, non-comprehensive set of representative use cases to further illustrate how this Framework can be utilized in SIP deployments. The first use case is simplistic in nature, whereas the second is relatively complex. The use cases illustrate the effectiveness of the framework in either scenario. For Security Considerations please refer to Section 5 and Section 9. @@ -606,38 +608,47 @@ for use with this framework. The following sub-sections provide the requirements associated with each stage. 5.1.1. Profile Enrollment Profile enrollment is the process by means of which a device requests, and receives, profile data. Each profile type specified in this document requires an independent enrollment request. However, a particular PDS can support enrollment for one or more profile types. + PDSs and devices MUST implement all the three profile types. A + device that has not been configured otherwise SHOULD try to obtain + all the three profile types, in the order specified by this + framework. The exceptions are bootstrapping when it SHOULD request + the device profile type (see Section 5.3.1) or when it has been + explicitly configured with a different order via mechanisms such as: + previously retrieved profile data, pre-configuration or manual + configuration. + Profile enrollment consists of the following operations, in the specified order. Enrollment request transmission Profile enrollment is initiated when the device transmits a SIP SUBSCRIBE request [RFC3265] for the 'ua-profile' event package, specified in Section 6. The profile being requested is indicated using the 'profile-type' parameter. The device MUST transmit the SIP SUBSCRIBE message via configured outbound proxies for the destination domain, or in accordance with RFC 3263 [RFC3263]. The device needs certain data to create an enrollment request, form a Request-URI, and authenticate to the network. This - includes the profile provider's domain name, identities and - credentials. Such data can be "configured" during device - manufacturing, by the user, or via profile data enrollment (see - Section 5.3.1). The data can also be "discovered" using the + includes the profile provider's domain name, device or user + identities and credentials. Such data can be "configured" during + device manufacturing, by the user, or via profile data enrollment + (see Section 5.3.1). The data can also be "discovered" using the procedures specified by this framework. The "discovered" data can be retained across device resets (but not across factory resets) and such data is referred to as "cached". Thus, data can be configured, discovered or cached. The following requirements apply. * If the device is configured with a specific domain name (for the local network provider or device provider), it MUST NOT attempt "discovery" of the domain name. This is the case when the device is pre-configured (e.g., via a user interface) to be @@ -648,21 +659,21 @@ 'example.net', it cannot present a user AoR associated with the local domain 'example.com'. * The device SHOULD adhere to the following order of data usage: configured, cached and discovered. An exception is when the device is explicitly configured to use a different order. Upon failure to obtain the profile using any methods specified in this framework, the device MAY provide a user interface to allow for user intervention. This can result in temporary, one-time data to bootstrap the device. Such temporary data is not - considered to be "configured" and SHOULD NOT not be cached across + considered to be "configured" and SHOULD NOT be cached across resets. The configuration obtained using such data MAY provide the configuration data required for the device to continue functioning normally. Devices attempting enrollment MUST comply with the SIP-specific event notification specified in [RFC3265], the event package requirements specified in Section 6.2, and the security requirements specified in Section 5.2. Enrollment request admittance @@ -762,21 +773,21 @@ describes the requirements for creating a SIP SUBSCRIBE for enrollment, the caching requirements and how data can be discovered. 5.1.4.1. Local-Network Profile To create a Subscription URI to request the local-network profile a device needs the local network domain name, the device identifier and optionally a user AoR with associated credentials (if one is configured). Since the device can be potentially initialized in a different local-network each time, it SHOULD NOT cache the local - network domain, the SIP subscription URI or the local-network profile + network domain, the SIP Subscription URI or the local-network profile data across resets. An exception to this is when the device can confirm that it is reinitialized in the same network (using means outside the scope of this document). Thus, in most cases, the device needs to discover the local network domain name. The device discovers this by establishing IP connectivity in the local network (such as via DHCP or pre-configured IP information). Once established, the device MUST attempt to use the local network domain obtained via pre-configuration, if available. If it is not pre- configured, it MUST employ dynamic discovery using DHCPv4 ([RFC2132], Domain Name option) or DHCPv6 ([RFC4704]). Once the local network @@ -775,30 +786,31 @@ outside the scope of this document). Thus, in most cases, the device needs to discover the local network domain name. The device discovers this by establishing IP connectivity in the local network (such as via DHCP or pre-configured IP information). Once established, the device MUST attempt to use the local network domain obtained via pre-configuration, if available. If it is not pre- configured, it MUST employ dynamic discovery using DHCPv4 ([RFC2132], Domain Name option) or DHCPv6 ([RFC4704]). Once the local network domain is obtained, the device creates the SIP SUBSCRIBE for enrollment as described below. + o The device MUST NOT populate the user part of the Request-URI. The device MUST set the host portion of the Request-URI to the dot-separated concatenation of "_sipuaconfig" and the local network domain (see example below). o If the device has been configured with a user AoR for the local - network domain (verified as explained in Section 5.2) it MUST use - it to populate the "From" field, unless configured not to (due to - privacy concerns, for example). Otherwise, the device MUST set - the "From" field to a value of "anonymous@anonymous.invalid". - + network domain (verified as explained in Section 5.2) the device + MUST use it to populate the "From" field, unless configured not to + (due to privacy concerns, for example). Otherwise, the device + MUST set the "From" field to a value of + "anonymous@anonymous.invalid". o The device MUST include the +sip.instance parameter within the 'Contact' header, as specified in [RFC5626]. The device MUST ensure that the value of this parameter is the same as that included in any subsequent profile enrollment request. For example, if the device requested and received the local domain name via DHCP to be: airport.example.net, then the local-network Profile SUBSCRIBE Request-URI would look like: sip:_sipuaconfig.airport.example.net @@ -826,21 +838,21 @@ change frequently. Thus, the device is allowed to, and SHOULD cache the Subscription URI for the device profile upon successful enrollment. Exceptions include cases where the device identifier has changed (e.g., new network card), device provider information has changed (e.g., user initiated change) or the device cannot obtain its profile using the Subscription URI. Thus, when available, the device MUST use a cached Subscription URI. If no cached URI is available then it needs to create a Subscription URI. To create a Subscription URI, the device needs a device identity and the device provider's domain name. Unless already configured, the device needs to discover - the necessary information and form the subscription URI. In such + the necessary information and form the Subscription URI. In such cases, the following requirements apply for creating a Subscription URI for requesting the device profile: o The device MUST populate the user part of the Request-URI with the device identifier. The device MUST set the host portion of the Request-URI to the domain name of the device provider. The device identifier format is explained in detail later in this section. o The device MUST set the "From" field to a value of anonymous@ . o The device MUST include the +sip.instance parameter within the @@ -864,21 +876,21 @@ domain name of the outbound proxy during the DHCP process, using the DHCP option for SIP servers defined in [RFC3361] or [RFC3319] (for IPv4 and IPv6 respectively). o Option 2: Devices that support DHCP MUST attempt to obtain the local IP network domain during the DHCP process (refer to [RFC2132] and [RFC4704] ). o Option 3: Devices MUST use the local network domain name (configured or discovered to retrieve the local-network profile), prefixing it with the label "_sipuaconfig". - If the device needs to create a subscription URI and needs to use its + If the device needs to create a Subscription URI and needs to use its device identifier, it MUST use the UUID-based URN representation as specified in [RFC4122]. The following requirements apply: o When the device has a non-alterable MAC address it SHOULD use version 1 UUID representation with the timestamp and clock sequence bits set to a value of '0'. This will allow for easy recognition, and uniqueness of MAC address based UUIDs. An exception is the case where the device supports independent device configuration for more than one SIP UA. An example would be multiple SIP UAs on the same platform. o If the device cannot use a non-alterable device identifier, it @@ -894,94 +905,99 @@ in the user part of an addr-spec ([RFC4122]), and must be escaped. For example, the instance ID: urn:uuid:f81d4fae-7ced-11d0-a765-00a0c91e6bf6@example.com would be escaped to look as follows in a URI: sip:urn%3auuid%3af81d4fae-7ced-11d0-a765-00a0c91e6bf6@ example.com - The ABNF for the UUID representation is provided in [RFC4122] + The ABNF ([RFC5234]) for the UUID representation is provided in + [RFC4122] 5.1.4.3. User Profile Type To create a Subscription URI to request the user profile on behalf of a user, the device needs to know the user's AoR. This can be statically or dynamically configured on the device (e.g., user input, or propagated as part of the device profile). Similar to device profiles, the content and propagation of user profiles may differ, based on deployment scenarios (i.e., users belonging to the same domain may - or may not - be provided the same profile). To create a - subscription URI, the following rules apply: + Subscription URI, the following rules apply: o The device MUST set the Request-URI to the user AoR. o The device MUST populate the "From" field with the user AoR. An authoritative SIP proxy for a SIP provider's network that receives a profile enrollment request for the user profile type will route based on the Event Header field values, thus allowing a subscription to the user's AoR to be routed to the appropriate PDS. 5.2. Securing Profile Delivery Profile data can contain sensitive information that needs to be secured, such as identities and credentials. Security involves - authentication, message integrity and privacy. Authentication is the - process by which you verify that an entity is who it claims to be, - such as a user AoR presented during profile enrollment. Message - integrity provides the assurance that the message contents - transmitted between two entities, such as between the PDS and the - device, has not been modified during transit. Privacy ensures that - the message contents have not been subjected to monitoring by - unwanted elements during transit. Authentication and message - integrity are required to ensure that the profile contents were + authentication, data integrity and data confidentiality. + Authentication is the process by which you verify that an entity is + who it claims to be, such as a user AoR presented during profile + enrollment. Message integrity provides the assurance that the + message contents transmitted between two entities, such as between + the PDS and the device, has not been modified during transit. + Privacy ensures that the message contents have not been subjected to + monitoring by unwanted elements during transit. Authentication and + data integrity are required to ensure that the profile contents were received by a valid entity, from a valid source, and without any modifications during transit. For profiles that contain sensitive - data, privacy is also required. + data, data confidentiality is also required. For an overview of potential security threats, refer to Section 9. For information on how the device can be configured with identities and credentials, refer to Section 5.3.1. The following subsections provide the security requirements associated with each profile delivery stage, and applies to each of profile types specified by this framework. 5.2.1. Securing Profile Enrollment Profile enrollment may result in sensitive profile data. In such cases, the PDS MUST authenticate the device, except during the bootstrapping scenario when the device does not have existing credentials (see Section 5.3.1 for more information on bootstrapping). Additionally, the device MUST authenticate the PDS to ensure that it is obtaining sensitive profile data from a valid PDS. To authenticate a device that has been configured with identities and credentials as specified in Section 5.3.1 and support profiles - containing sensitive profile data (refer to Section 5.3.4), devices - and PDSs MUST support Digest Authentication as specified in - [RFC3261]. Future enhancements may provide other authentication + containing sensitive profile data (refer to Section 5.3.3), devices + and PDSs MUST support Digest Authentication (over TLS) as specified + in [RFC3261]. Future enhancements may provide other authentication methods such as authentication using X.509 certificates. For the device to authenticate the PDS, the device MUST mutually authenticate with the PDS during digest authentication (device challenges the PDS, which responds with the Authorization header). Transmission of - sensitive profile data also requires message integrity. This can be + sensitive profile data also requires data integrity. This can be accomplished by configuring the device with, or by ensuring that the discovery process during profile enrollment provides, a SIPS URI resulting in TLS establishment ([RFC5246]). TLS also prevents offline dictionary attacks when digest authentication is used. Thus, in the absence of TLS, the device MUST NOT respond to any authentication challenges. It is to be noted that the digest credentials used for obtaining profile data via this framework may, or may not, be the same as that used for SIP registration (see - Section 5.3.1). + Section 5.3.1). In addition, while [RFC3261] considers MD5 to be a + reasonable choice to compute the hash, and this may have been true + when [RFC3261] was published, implementers are recommended to use + stronger alternatives such as SHA-256. Refer to [FIPS-180-3] and + [RFC4634] for more information about SHA-256. When the PDS challenges a profile enrollment request, and it fails, the PDS MAY refuse enrollment or provide profile data without the user-specific information (e.g., to bootstrap a device as indicated in Section 5.3.1). If the device challenges, but fails to authenticate the PDS, it MUST reject the initial notification and retry the profile enrollment process. If the device is configured with, or discovers, a SIPS URI but TLS establishment fails because the next-hop SIP entity does not support TLS, the device SHOULD attempt other resolved next-hop SIP entities. When the device @@ -1020,39 +1036,39 @@ If the profile is provided via content indirection and contains sensitive profile data then the PDS MUST use a HTTPS URI for content indirection. PCCs and devices MUST NOT use HTTP for sensitive profile data, except for bootstrapping a device via the device profile. A device MUST authenticate the PCC as specified in [RFC2818], Section 3.1. A device that is being provided with profile data that contains sensitive data MUST be authenticated using digest authentication as specified in [RFC2617], with the exception of a device that is being bootstrapped for the first time via the device - profile. The resulting TLS channel also provides message integrity - and privacy. + profile. The resulting TLS channel also provides data integrity and + data confidentiality. 5.2.3. Securing Change Notification If the device requested enrollment via a SIP subscription with a non- zero 'Expires' parameter, it can also result in change notifications for the duration of the subscription. For change notifications containing sensitive profile data, this framework RECOMMENDS the use of the SIP Identity header as specified in [RFC4474]. When the SIP Identity header is used, the PDS MUST set the host portion of the AoR in the 'From' header to the Provider's domain (the user portion is a entity-specific identifier). This provides header and body integrity - as well. However, for sensitive profile data requiring privacy, if - the contact URI to which the NOTIFY request is to be sent is not - SIPS, the PDS MUST use content indirection. Additionally, the PDS - MUST also use content indirection for notifications containing - sensitive profile data, when the profile enrollment was not - authenticated. + as well. However, for sensitive profile data requiring data + confidentiality , if the contact URI to which the NOTIFY request is + to be sent is not SIPS, the PDS MUST use content indirection. + Additionally, the PDS MUST also use content indirection for + notifications containing sensitive profile data, when the profile + enrollment was not authenticated. 5.3. Additional Considerations This section provides additional considerations such as details on how a device obtains identities and credentials, backoff and retry methods, guidelines on profile data and additional profile types. 5.3.1. Bootstrapping Identities and Credentials When requesting a profile the profile delivery server will likely @@ -1098,27 +1114,32 @@ For example, the profile data can direct the end-user to a web portal to obtain a subscription. Upon obtaining a successful subscription, the end-user or the device can be provided with the necessary identities and credentials. * Content indirection information to a PCC that can provide identities and credentials. As an example, consider a device that has a X.509 certificate that can be authenticated by the PCC. In such a case, the PCC can use HTTPS to provide identities and associated credentials. * Profile data containing identities and credentials that can be - used to bootstrap the device (see Section 5.3.4 for profile + used to bootstrap the device (see Section 5.3.3 for profile data recommendations). This can be used in cases where the device is initialized for the first time, or after a factory reset. This can be considered only in cases where the device is initialized in the Provider's network, for obvious security reasons. + For interoperability purposes, this framework requires PDSs and + devices to support the last option (above), which is to use this + framework. Specifically, the option of providing identities and + credentials via the profile data MUST be supported. + Additionally, AoRs are typically known by PDSs that serve the domain indicated by the AoR. Thus, devices can only present the configured AoRs in the respective domains. An exception is the use of federated identities. This allows a device to use a user's AoR in multiple domains. Further even within the same domain, the device's domain proxy and the PDS may be in two different realms, and as such may be associated with different credentials for digest authentication. In such cases, multiple credentials may be configured, and associated with the realms in which they are to be used. This framework specifies only digest authentication for profile enrollment and the @@ -1254,117 +1275,104 @@ supported by the profile data model; not to be confused with an empty NOTIFY), or via an explicit profile data element that invalidates the data. A device receiving such a NOTIFY MUST discard the applicable profile (i.e., it cannot even store it in the cache). Additionally, if a factory reset is available and performed on a device, it MUST reset the device to its initial state prior to any configuration. Specifically, the device MUST set the device back to the state when it was originally distributed. The order of profile enrollment is important. For the profiles - specified in this framework, the device must enroll in the following + specified in this framework, the device MUST enroll in the following default order: local-network, device and user. The pseudo-code presented earlier (Figure 7) differentiates between 'mandatory' and 'non-mandatory' profiles. This distinction is left to profile data definitions. It is to be noted that this framework does not allow the devices to inform the PDSs of profile retrieval errors such as invalid data. Follow-on standardization activities are expected to address this feature. -5.3.3. Device Types - - The examples in this framework tend to associate devices with - entities that are accessible to end-users. However, this is not - necessarily the only type of device that can utilize the specified - Framework. Devices can be entities such as SIP Phones or soft - clients, with or without user interfaces (that allow for device - Configuration), entities in the network that do not directly - communicate with any users (e.g., gateways, media servers, etc) or - network infrastructure elements e.g., SIP servers). - -5.3.4. Profile Data +5.3.3. Profile Data This framework does not specify the contents for any profile type. Follow-on standardization activities are expected to address profile contents. However, the framework provides the following requirements and recommendations for profile data definitions: o The device profile type SHOULD specify parameters to configure the identities and credentials for use in scenarios such as bootstrapping (see Section 5.3.1) and run-time modifications to identities and credentials. This framework recommends the device - profile to provide the identities and credentials due to a couple - of reasons. The local-network profile may not always be - available, and even if present, may not be controlled by the - device provider who controls device configuration to provide - services. Further, the device may not have any users configured - prior to being bootstrapped, resulting in an absence of user - profile requests. However, this framework does not prevent other - profile types from providing identities and credentials to meet - deployment needs. For example, the user profile can contain - identities and credentials for communicating with specific - applications. + profile provide the identities and credentials due to a couple of + reasons. The local-network profile may not always be available, + and even if present, may not be controlled by the device provider + who controls device configuration to provide services. Further, + the device may not have any users configured prior to being + bootstrapped, resulting in an absence of user profile requests. + However, this framework does not prevent other profile types from + providing identities and credentials to meet deployment needs. + For example, the user profile can contain identities and + credentials for communicating with specific applications. o Each profile MUST clearly identify if it may contain any sensitive data. Such profiles MUST also identify the data elements that are - considered sensitive, i.e., data that cannot be compromised. As - an example, a device profile definition may identify itself as - containing sensitive data and indicate data such as device - credentials to be sensitive. + considered sensitive, i.e., data that cannot be disclosed to + unauthorized parties. As an example, a device profile definition + may identify itself as containing sensitive data and indicate data + such as device credentials to be sensitive. o When the device receives multiple profiles, the contents of each profile type SHOULD only contain data relevant to the entity it represents. As an example, consider a device that obtains all the defined profiles. Information pertaining to the local network is contained in the 'local-network' profile and not the 'user' profile. This does not preclude relevant data about a different entity from being included in a profile type, e.g., the 'device' profile type may contain information about the users allowed to access services via the device. A profile may also contain starting information to obtain subsequent Profiles. o Data overlap SHOULD be avoided across profile types, unless necessary. If data overlap is present, prioritization of the data is left to data definitions. As an example, the device profile may contain the list of codecs to be used by the device and the user Profile (for a user on the device) may contain the codecs preferred by the user. Thus, the same data (usable codecs) is present in two profiles. However, the data definitions may indicate that to function effectively, any codec chosen for communication needs to be present in both the profiles. -5.3.5. Profile Data Frameworks +5.3.4. Profile Data Frameworks The framework specified in this document does not address profile data representation, storage or retrieval protocols. It assumes that the PDS has a PCC based on existing or other Profile Data Frameworks. While this framework does not impose specific constraints on any such framework, it does allow for the propagation of profile content to - the PDS (specifically the PCC) from a network element or the device. - Thus, Profile Data or Retrieval frameworks used in conjunction with - this framework MAY consider techniques for propagating incremental, - atomic changes to the PDS. One means for propagating changes to a - PDS is defined in XCAP ([RFC4825]). + the PDS (specifically the PCC). Thus, Profile Data or Retrieval + frameworks used in conjunction with this framework MAY consider + techniques for propagating incremental, atomic changes to the PDS. + One means for propagating changes to a PDS is XCAP ([RFC4825]). -5.3.6. Additional Profile Types +5.3.5. Additional Profile Types This document specifies three profile types: local-network, device and user. However, there may be use cases for additional profile types. e.g., profile types for application specific profile data or to provide enterprise-specific policies. Definition of such additional profile types is not prohibited, but considered out of scope for this document. Such profile definitions MUST specify the order of retrieval with respect to all the other profiles such as the local-network, device and user profile types defined in this document. -5.3.7. Deployment considerations +5.3.6. Deployment considerations The framework defined in this document was designed to address various deployment considerations, some of which are highlighted below. Provider relationships: o The local network provider and the SIP service provider can often be different entities, with no administrative or business relationship with each other. o There may be multiple SIP service providers involved, one for each @@ -1473,41 +1481,44 @@ 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. 6.2.2. vendor, model and version 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 PDS to affect the profiles - provided. In some scenarios it is desirable to provide different - profiles based upon these parameters. e.g., feature property X in a - profile may work differently on two versions of the same user agent. - This gives the PDS the ability to compensate for or take advantage of - the differences. In the following ABNF defining the syntax, EQUAL - and quoted-string are defined in [RFC3261]. + the value of the "vendor" parameter so that it is known to be unique, + unless there is a good reason not to. Examples of exceptions + include: if the vendor does not have an assigned DNS domain name, if + they are using a different vendor's implementation etc. These + parameters are useful to the PDS to affect the profiles provided. In + some scenarios it is desirable to provide different profiles based + upon these parameters. e.g., feature property X in a profile may work + differently on two versions of the same user agent. This gives the + PDS the ability to compensate for or take advantage of the + differences. In the following ABNF defining the syntax, EQUAL and + quoted-string are defined in [RFC3261]. Vendor = "vendor" EQUAL quoted-string Model = "model" EQUAL quoted-string Version = "version" EQUAL quoted-string 6.2.3. effective-by parameter 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" + 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 + user agent MUST attempt to make the profiles effective immediately (despite possible service interruptions). This gives the PDS the power to control when the profile is effective. This may be important to resolve an emergency problem or disable a user agent immediately. If it is absent, the device SHOULD attempt to make the profile data effective at the earliest possible opportunity that does not disrupt any services being offered. 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 @@ -1535,23 +1546,23 @@ The following table shows the use of Event header parameters in SUBSCRIBE requests for the three profile types: profile-type || device | user | local-network ============================================= vendor || m | m | m model || m | m | m version || m | m | m effective-by || | | - m - mandatory + m - MUST be provided s - SHOULD be provided - o - optional + o - OPTIONAL to be provided 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 three profile types: profile-type || device | user | local-network ============================================= vendor || | | @@ -1670,21 +1681,21 @@ This Event package allows the creation of only one dialog as a result of an initial SUBSCRIBE request as described in section 4.4.9 of [RFC3265]. It does not support the creation of multiple subscriptions using forked SUBSCRIBE requests. 6.10. Rate of Notifications The rate of notifications for the profiles in this framework is deployment specific, but expected to be infrequent. Hence, the Event Package specification does not specify a throttling or minimum period - between NOTIFY requests + between NOTIFY requests. 6.11. State Agents State agents are not applicable to this Event Package. 7. Examples This section provides examples along with sample SIP message bodies relevant to this framework. Both the examples are derived from the use case illustrated in Section 4.1, specifically the request for the @@ -2049,65 +2060,66 @@ other SIP proxies, if required). When a PDS receives the enrollment request, it can either challenge any contained identity or admit the enrollment. Authorization rules then decide if the enrollment gets accepted. If accepted, the PDS sends an initial notification that contains either the profile data, or content indirection information. The profile data can contain generic profile data (common across multiple devices) or information specific to an entity (such as the device or a user). If specific to an entity, it may contain sensitive information such as credentials. - Compromise of sensitive data can lead to threats such as + Disclosure of sensitive data can lead to threats such as impersonation attacks (establishing rogue sessions), theft of service (if services are obtainable), and zombie attacks. It is important for the device to ensure the authenticity of the PNC and the PCC since impersonation of the SIP service provider can lead to Denial of Service and Man-in-the-Middle attacks. Profile content retrieval allows a device to retrieve profile data via content indirection from a PCC. This communication is accomplished using one of many profile delivery protocols or frameworks, such as HTTP or HTTPS as specified in this document. However, since the profile data returned is subject to the same considerations as that sent via profile notification, similar threats exist. For example, denial of service attacks (rogue devices bombard the PCC with requests for a specific profile) and attempts to modify erroneous data onto the PCC (since the location and format may be known). Thus, for the delivery of any sensitive profile data, authentication of the entity requesting profile data is required. It is also important for the requesting entity to authenticate the profile source via content indirection, and ensure that the sensitive - profile data is protected via message integrity. For sensitive data - that should not be subject to snooping, privacy is also required. + profile data is protected via data integrity. For sensitive data + that should not be disclosed to unauthorized parties, data + confidentiality is also required. The following sub-sections highlight the security considerations that are specific to each profile type. 9.1. Local-network profile A local network may or may not (e.g., home router) support local- network profiles as specified in this framework. Even if supported, the PDS may only be configured with a generic local-network profile that is provided to every device that requests the local-network profile. Such a PDS may not implement any authentication requirements or TLS. Alternatively, certain deployments may require the entities - device and the PDS - to authenticate each other prior to successful profile enrollment. Such networks may pre-configure user identities to the devices and allow user-specific local-network profiles. In such - networks the PDS will support digest, and the devices are configured - with user identities and credentials as specified in Section 5.3.1. - If sensitive profile data is being transmitted, the user identity is - a SIPS URI that results in TLS with the next-hop (which is - authenticated), and digest authentication is used by the PDS and the - device. + networks the PDS will support digest authentication, and the devices + are configured with user identities and credentials as specified in + Section 5.3.1. If sensitive profile data is being transmitted, the + user identity is a SIPS URI that results in TLS with the next-hop + (which is authenticated), and digest authentication is used by the + PDS and the device. This framework supports both use cases and any variations in-between. However, devices obtaining local-network profiles from an unauthenticated PDS are cautioned against potential Man-in-the-Middle or PDS impersonation attacks. This framework requires that a device reject sensitive data, such as credentials, from unauthenticated local-network sources. It also prohibits devices from responding to authentication challenges in the absence of TLS on all hops as a result of using a SIPS URI. Responding to unauthenticated challenges allows for dictionary attacks that can reveal weak passwords. The @@ -2153,121 +2165,118 @@ If not, the device can still guarantee header and body integrity if the profile data contains the domain certificate (but the data can still be invalid or malicious). In such cases, devices supporting user interfaces may obtain confirmation from the user trying to bootstrap the device (confirming header and body integrity). However, when the SIP Identity header is not present, or the device is not capable of validating it, the bootstrapping data is unauthenticated and obtained without any integrity protection. Such bootstrapping data, however, may contain only temporary credentials (SIPS URI and digest credentials) that can be used to reconnect to - the network to ensure message integrity and privacy prior to - obtaining long-term credentials. It is to be noted that such devices - are at the mercy of the network they request the device profile from. - If they are initialized in a rogue network, or get hijacked by a - rogue PDS, the end-user may be left without desired device operation - or, worse, unwanted operation. To mitigate such factors the device - provider may communicate temporary credentials (e.g., passwords that - can be entered via an interface) or permanent credentials (e.g., a - USB device) to the end-user for connectivity. If such methods are - used, those credentials MUST be quickly replaced by large-entropy - credentials, to minimize the impact of dictionary attacks. Future - enhancements to this framework may specify device capabilities that - allow for authentication without any provider specific configuration - (e.g., X.509 certificates using PKI can allow for authentication by - any provider with access to the CA certificate). Alternatively, the - device may be pre-configured with with credentials for use with - content indirection mechanisms. In such circumstances a PDS can use - secure content indirection mechanism, such as HTTPS, to provide the - bootstrapping data. + the network to ensure data integrity and data confidentiality prior + to obtaining long-term credentials. It is to be noted that such + devices are at the mercy of the network they request the device + profile from. If they are initialized in a rogue network, or get + hijacked by a rogue PDS, the end-user may be left without desired + device operation or, worse, unwanted operation. To mitigate such + factors the device provider may communicate temporary credentials + (e.g., passwords that can be entered via an interface) or permanent + credentials (e.g., a USB device) to the end-user for connectivity. + If such methods are used, those credentials MUST be quickly replaced + by large-entropy credentials, to minimize the impact of dictionary + attacks. Future enhancements to this framework may specify device + capabilities that allow for authentication without any provider + specific configuration (e.g., X.509 certificates using PKI can allow + for authentication by any provider with access to the CA + certificate). Alternatively, the device may be pre-configured with + with credentials for use with content indirection mechanisms. In + such circumstances a PDS can use secure content indirection + mechanism, such as HTTPS, to provide the bootstrapping data. Once a device is associated with a device provider the device profile is vital to device operation. This is because the device profile can contain important operational information such as users that are to be allowed access (white-list or black-list), user credentials (if required) and other sensitive information. Thus, it is necessary to ensure that any device profile containing sensitive information is obtained via an authenticated source, with integrity protection, and delivered to an authenticated device. For sensitive information such - as credentials, privacy is also required. The framework requires - that devices obtain sensitive information only from authenticated - entities except while it is being bootstrapped. In cases where - privacy needs to be mandated for notifications, the device provider - can configure the device with a SIPS URI, to be used as the - subscription URI, during profile enrollment. The framework also - requires a PDS presenting sensitive profile data to use digest - authentication. This ensures that the data is delivered to an - authenticated entity. Authentication of profile retrieval via - content indirection for sensitive profiles is via HTTPS utilizing - HTTP digest. + as credentials, data confidentiality is also required. The framework + requires that devices obtain sensitive information only from + authenticated entities except while it is being bootstrapped. In + cases where data confidentiality needs to be mandated for + notifications, the device provider can configure the device with a + SIPS URI, to be used as the Subscription URI, during profile + enrollment. The framework also requires a PDS presenting sensitive + profile data to use digest authentication. This ensures that the + data is delivered to an authenticated entity. Authentication of + profile retrieval via content indirection for sensitive profiles is + via HTTPS utilizing HTTP digest. 9.3. User profile Devices can only request user profiles for users that are known by a SIP service provider. PDSs are required to reject user profile enrollment requests for any users that are unknown in the network. For known user AoRs that are allowed to retrieve profiles, the security considerations are similar to that of the device profile (except for bootstrapping). 10. Acknowledgements The author appreciates all those who contributed and commented on the many iterations of this document. Detailed comments were provided by - the following individuals: Jonathan Rosenberg from Cisco, Henning - Schulzrinne from Columbia University, Cullen Jennings from Cisco, - Rohan Mahy from Plantronics, 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, Francois Audet from Nortel, Roni Even from - Polycom, Jason Fischl from Counterpath, Josh Littlefield from Cisco, - Nhut Nguyen from Samsung. + the following individuals: Jonathan Rosenberg, Henning Schulzrinne, + Cullen Jennings, Rohan Mahy, Rich Schaaf, Volker Hilt, Adam Roach, + Hisham Khartabil, Henry Sinnreich, Martin Dolly, John Elwell, Elliot + Eichen, Robert Liao, Dale Worley, Francois Audet, Roni Even, Jason + Fischl, Josh Littlefield, and Nhut Nguyen. The final revisions of this document were a product of design team discussions. The editor wishes to extend special appreciation to the following design team members for their numerous reviews and specific - contributions to various sections: Josh Littlefield from Cisco - (Overview, Section 6), Peter Blatherwick from Mitel (Section 6), - Cullen Jennings (Security), Sam Ganesan (Section 6) and Mary Barnes - (layout, Section 6). + contributions to various sections: Josh Littlefield (Overview, + Section 6), Peter Blatherwick (Section 6), Cullen Jennings + (Security), Sam Ganesan (Section 6) and Mary Barnes (layout, Section + 6). The following design team members are thanked for numerous reviews and general contributions: Martin Dolly from AT&T Labs, Jason Fischl from Counterpath, Alvin Jiang of Engin and Francois Audet from Nortel. The following SIPPING WG members are thanked for numerous reviews, - comments and recommendations: John Elwell from Siemens, Donald Lukacs - from Telcordia, Roni Even from Polycom, David Robbins from Verizon, - Shida Schubert from NTT Advanced Technology Corporation, and Eugene - Nechamkin from Broadcom. The editor would also like to extend a - special thanks to the comments and recommendations provided by the - SIPPING WG, specifically Keith Drage from Lucent (restructuring - proposal) and John Elwell from Siemens (numerous reviews and + comments and recommendations: John Elwell, Donald Lukacs, Roni Even, + David Robbins, Shida Schubert, and Eugene Nechamkin. The editor + would also like to extend a special thanks to the comments and + recommendations provided by the SIPPING WG, specifically Keith Drage + (restructuring proposal) and John Elwell (numerous reviews and recommendations). Additionally, appreciation is also due to Peter Koch for expert DNS advice. And finally, sincere appreciation is extended to the chairs (Mary - Barnes from Nortel and Gonzalo Camarillo from Ericsson), the past/ - current Area Directors (Cullen Jennings from Cisco, Jon Peterson from - Neustar, and Robert Sparks from Tekelec) for facilitating + Barnes and Gonzalo Camarillo), the past/current Area Directors + (Cullen Jennings, Jon Peterson, and Robert Sparks) for facilitating discussions, reviews and contributions; and, the expert reviewers - from the IESG (Peter McCann from Motorola, Catherine Meadows from - Naval Research Laboratory). + from the IESG (Peter McCann, Catherine Meadows). 11. References 11.1. Normative References + [FIPS-180-3] + National Institute of Standards and Technology (NIST), + "Secure Hash Standard (SHS)", FIPS PUB 180-3, + October 2008. + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [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", @@ -2308,53 +2317,59 @@ May 2006. [RFC4704] Volz, B., "The Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Client Fully Qualified Domain Name (FQDN) Option", RFC 4704, October 2006. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. + [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax + Specifications: ABNF", STD 68, RFC 5234, January 2008. + [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, August 2008. [RFC5626] Jennings, C., Mahy, R., and F. Audet, "Managing Client- Initiated Connections in the Session Initiation Protocol (SIP)", RFC 5626, October 2009. 11.2. Informative References [I-D.ietf-ecrit-phonebcp] Rosen, B. and J. Polk, "Best Current Practice for Communications Services in support of Emergency Calling", - draft-ietf-ecrit-phonebcp-14 (work in progress), - January 2010. + draft-ietf-ecrit-phonebcp-15 (work in progress), + July 2010. [RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol", STD 9, RFC 959, October 1985. [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. [RFC4510] Zeilenga, K., "Lightweight Directory Access Protocol (LDAP): Technical Specification Road Map", RFC 4510, June 2006. + [RFC4634] Eastlake, D. and T. Hansen, "US Secure Hash Algorithms + (SHA and HMAC-SHA)", RFC 4634, July 2006. + [RFC4825] Rosenberg, J., "The Extensible Markup Language (XML) Configuration Access Protocol (XCAP)", RFC 4825, May 2007. Authors' Addresses Daniel Petrie SIPez LLC. - 34 Robbins Rd + 246A Park Ave Arlington, MA 02476 USA Email: dan.ietf AT SIPez DOT com URI: http://www.SIPez.com/ Sumanth Channabasappa (Editor) CableLabs 858 Coal Creek Circle Louisville, Co 80027