< draft-ietf-sipping-config-framework-14.txt   draft-ietf-sipping-config-framework-15.txt >
SIPPING D. Petrie SIPPING D. Petrie
Internet-Draft SIPez LLC. Internet-Draft SIPez LLC.
Intended status: Standards Track S. Channabasappa, Ed. Intended status: Standards Track S. Channabasappa, Ed.
Expires: May 21, 2008 CableLabs Expires: August 16, 2008 CableLabs
November 18, 2007 February 13, 2008
A Framework for Session Initiation Protocol User Agent Profile Delivery A Framework for Session Initiation Protocol User Agent Profile Delivery
draft-ietf-sipping-config-framework-14 draft-ietf-sipping-config-framework-15
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware 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 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. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
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This Internet-Draft will expire on May 21, 2008. This Internet-Draft will expire on August 16, 2008.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2008).
Abstract Abstract
This document specifies a framework to enable configuration of This document specifies a framework to enable configuration of
Session Initiation Protocol (SIP) User Agents in SIP deployments. Session Initiation Protocol (SIP) User Agents in SIP deployments.
The framework provides a means to deliver profile data that User The framework provides a means to deliver profile data that User
Agents need to be functional, automatically and with minimal or no Agents need to be functional, automatically and with minimal or no
User and Administrative intervention. The framework describes how User and Administrative intervention. The framework describes how
SIP User Agents can discover sources, request profiles and receive SIP User Agents can discover sources, request profiles and receive
notifications related to profile modifications. As part of this notifications related to profile modifications. As part of this
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Service Providers . . . . . . . . . . . . . . . . . . . . 12 Service Providers . . . . . . . . . . . . . . . . . . . . 12
5. Profile Delivery Framework . . . . . . . . . . . . . . . . . . 14 5. Profile Delivery Framework . . . . . . . . . . . . . . . . . . 14
5.1. Profile delivery stages . . . . . . . . . . . . . . . . . 14 5.1. Profile delivery stages . . . . . . . . . . . . . . . . . 14
5.1.1. Profile Enrollment . . . . . . . . . . . . . . . . . . 15 5.1.1. Profile Enrollment . . . . . . . . . . . . . . . . . . 15
5.1.2. Content Retrieval . . . . . . . . . . . . . . . . . . 17 5.1.2. Content Retrieval . . . . . . . . . . . . . . . . . . 17
5.1.3. Change Notification . . . . . . . . . . . . . . . . . 17 5.1.3. Change Notification . . . . . . . . . . . . . . . . . 17
5.1.4. Enrollment Data and Caching . . . . . . . . . . . . . 18 5.1.4. Enrollment Data and Caching . . . . . . . . . . . . . 18
5.2. Securing Profile Delivery . . . . . . . . . . . . . . . . 21 5.2. Securing Profile Delivery . . . . . . . . . . . . . . . . 21
5.2.1. Securing Profile Enrollment . . . . . . . . . . . . . 22 5.2.1. Securing Profile Enrollment . . . . . . . . . . . . . 22
5.2.2. Securing Content Retrieval . . . . . . . . . . . . . . 23 5.2.2. Securing Content Retrieval . . . . . . . . . . . . . . 23
5.2.3. Securing Change Notification . . . . . . . . . . . . . 23 5.2.3. Securing Change Notification . . . . . . . . . . . . . 24
5.3. Additional Considerations . . . . . . . . . . . . . . . . 24 5.3. Additional Considerations . . . . . . . . . . . . . . . . 24
5.3.1. Identities and Credentials . . . . . . . . . . . . . . 24 5.3.1. Bootstrapping Identities and Credentials . . . . . . . 24
5.3.2. Profile Enrollment Request Attempt . . . . . . . . . . 25 5.3.2. Profile Enrollment Request Attempt . . . . . . . . . . 26
5.3.3. Device Types . . . . . . . . . . . . . . . . . . . . . 29 5.3.3. Device Types . . . . . . . . . . . . . . . . . . . . . 30
5.3.4. Profile Data . . . . . . . . . . . . . . . . . . . . . 29 5.3.4. Profile Data . . . . . . . . . . . . . . . . . . . . . 30
5.3.5. Profile Data Frameworks . . . . . . . . . . . . . . . 30 5.3.5. Profile Data Frameworks . . . . . . . . . . . . . . . 31
5.3.6. Additional Profile Types . . . . . . . . . . . . . . . 31 5.3.6. Additional Profile Types . . . . . . . . . . . . . . . 32
5.3.7. Deployment considerations . . . . . . . . . . . . . . 31 5.3.7. Deployment considerations . . . . . . . . . . . . . . 32
5.4. Support for NATs . . . . . . . . . . . . . . . . . . . . . 31 5.4. Support for NATs . . . . . . . . . . . . . . . . . . . . . 33
6. Event Package Definition . . . . . . . . . . . . . . . . . . . 32 6. Event Package Definition . . . . . . . . . . . . . . . . . . . 33
6.1. Event Package Name . . . . . . . . . . . . . . . . . . . . 32 6.1. Event Package Name . . . . . . . . . . . . . . . . . . . . 33
6.2. Event Package Parameters . . . . . . . . . . . . . . . . . 32 6.2. Event Package Parameters . . . . . . . . . . . . . . . . . 33
6.3. SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . . 35 6.3. SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . . 36
6.4. Subscription Duration . . . . . . . . . . . . . . . . . . 35 6.4. Subscription Duration . . . . . . . . . . . . . . . . . . 37
6.5. NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . 36 6.5. NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . 37
6.6. Notifier Processing of SUBSCRIBE Requests . . . . . . . . 36 6.6. Notifier Processing of SUBSCRIBE Requests . . . . . . . . 37
6.7. Notifier Generation of NOTIFY Requests . . . . . . . . . . 36 6.7. Notifier Generation of NOTIFY Requests . . . . . . . . . . 38
6.8. Subscriber Processing of NOTIFY Requests . . . . . . . . . 37 6.8. Subscriber Processing of NOTIFY Requests . . . . . . . . . 38
6.9. Handling of Forked Requests . . . . . . . . . . . . . . . 37 6.9. Handling of Forked Requests . . . . . . . . . . . . . . . 39
6.10. Rate of Notifications . . . . . . . . . . . . . . . . . . 38 6.10. Rate of Notifications . . . . . . . . . . . . . . . . . . 39
6.11. State Agents . . . . . . . . . . . . . . . . . . . . . . . 38 6.11. State Agents . . . . . . . . . . . . . . . . . . . . . . . 39
7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
7.1. Example 1: Device requesting profile . . . . . . . . . . . 38 7.1. Example 1: Device requesting profile . . . . . . . . . . . 39
7.2. Example 2: Device obtaining change notification . . . . . 41 7.2. Example 2: Device obtaining change notification . . . . . 42
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 45 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46
8.1. SIP Event Package . . . . . . . . . . . . . . . . . . . . 45 8.1. SIP Event Package . . . . . . . . . . . . . . . . . . . . 46
8.2. Registry of SIP configuration profile types . . . . . . . 45 8.2. Registry of SIP configuration profile types . . . . . . . 46
9. Security Considerations . . . . . . . . . . . . . . . . . . . 46 9. Security Considerations . . . . . . . . . . . . . . . . . . . 47
9.1. Local-network profile . . . . . . . . . . . . . . . . . . 47 9.1. Local-network profile . . . . . . . . . . . . . . . . . . 48
9.2. Device profile . . . . . . . . . . . . . . . . . . . . . . 48 9.2. Device profile . . . . . . . . . . . . . . . . . . . . . . 49
9.3. User profile . . . . . . . . . . . . . . . . . . . . . . . 50 9.3. User profile . . . . . . . . . . . . . . . . . . . . . . . 51
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 50 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 51
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 51 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 52
11.1. Normative References . . . . . . . . . . . . . . . . . . . 51 11.1. Normative References . . . . . . . . . . . . . . . . . . . 52
11.2. Informative References . . . . . . . . . . . . . . . . . . 52 11.2. Informative References . . . . . . . . . . . . . . . . . . 53
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 52 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 54
Intellectual Property and Copyright Statements . . . . . . . . . . 54 Intellectual Property and Copyright Statements . . . . . . . . . . 55
1. Introduction 1. Introduction
SIP User Agents require configuration data to function properly. SIP User Agents require configuration data to function properly.
Examples include local network, device and user specific information. Examples include local network, device and user specific information.
A configuration data set specific to an entity is termed a profile. A configuration data set specific to an entity is termed a profile.
For example, device profile contains the configuration data related For example, device profile contains the configuration data related
to a device. The process of providing devices with one or more to a device. The process of providing devices with one or more
profiles is termed profile delivery. Ideally, this profile delivery profiles is termed profile delivery. Ideally, this profile delivery
process should be automatic and require minimal or no user process should be automatic and require minimal or no user
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| |
| |
---- ----
|User| |User|
---- ----
Figure 2: Simple Deployment Model Figure 2: Simple Deployment Model
In more complex deployments, devices connect via a local network that In more complex deployments, devices connect via a local network that
is not controlled by the SIP Service Provider, such as devices that is not controlled by the SIP Service Provider, such as devices that
connect via available public WiFi hotspots. In such cases, local connect via available public WiFi hot spots. In such cases, local
network providers may wish to provide local network information such network providers may wish to provide local network information such
as bandwidth constraints to the devices. as bandwidth constraints to the devices.
Devices may also be controlled by device providers that are Devices may also be controlled by device providers that are
independent of the SIP service provider who provides user services, independent of the SIP service provider who provides user services,
such as kiosks that allow users to access services from remote such as kiosks that allow users to access services from remote
locations. In such cases the profile data may have to be obtained locations. In such cases the profile data may have to be obtained
from different profile sources: local network provider, device from different profile sources: local network provider, device
provider and SIP service provider. This is indicated in Figure 3 . provider and SIP service provider. This is indicated in Figure 3 .
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Device Profile: contains configuration data related to a specific Device Profile: contains configuration data related to a specific
device, provided by the Device Provider. device, provided by the Device Provider.
User Profile: contains configuration data related to a specific User Profile: contains configuration data related to a specific
User, as required to reflect that user's preferences and the User, as required to reflect that user's preferences and the
particular services subscribed to. It is provided by the SIP particular services subscribed to. It is provided by the SIP
Service Provider. Service Provider.
Additional profile types may also be specified. Additional profile types may also be specified.
PDSs and devices will implement all the three profile types. A PDSs and devices will implement all the three profile types. A
device that has not been configured otherwise will try to obtain all device that has not been configured otherwise will try to obtain all
the three profile types, in the order specified by this framework. the three profile types, in the order specified by this framework. A
The device can be configuration with a different behavior via profile device being bootstrapped SHOULD request the device profile type (see
data previously obtained by the device, other means such as pre- Section 5.3.1 for more information). The device can be configured
configuration or manual configuration. The data models associated with a different behavior via profile data previously obtained by the
with each profile type are out of scope for this document. Follow-on device, or by using other means such as pre-configuration or manual
standardization activities are expected to specify such data models. 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.
3.4. Profile delivery stages 3.4. Profile delivery stages
The framework specified in this document requires a device to The framework specified in this document requires a device to
explicitly request profiles. It also requires one or more PDSs which explicitly request profiles. It also requires one or more PDSs which
provide the profile data. The processes that lead a device to obtain provide the profile data. The processes that lead a device to obtain
profile data, and any subsequent changes, can be explained in three profile data, and any subsequent changes, can be explained in three
stages, termed the profile delivery stages. stages, termed the profile delivery stages.
Profile Enrollment: the process by which a device requests, and if Profile Enrollment: the process by which a device requests, and if
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parameters using DHCP. This also provides the local domain parameters using DHCP. This also provides the local domain
information to help with local-network profile enrollment. information to help with local-network profile enrollment.
(B) The device requests profile enrollment for the local network (B) The device requests profile enrollment for the local network
profile. It receives an enrollment notification containing profile. It receives an enrollment notification containing
content indirection information from Provider A's PDS. The content indirection information from Provider A's PDS. The
device retrieves the profile (this contains useful information device retrieves the profile (this contains useful information
such as firewall port restrictions and available bandwidth). such as firewall port restrictions and available bandwidth).
(C) The device then requests profile enrollment for the device (C) The device then requests profile enrollment for the device
profile. It receives an enrollment notification resulting in profile. It receives an enrollment notification resulting in
device profile content retrieval. The device initializes the device profile content retrieval. The device initializes the
User interface for services. user interface for services.
(D) User A with a pre-existing service relationship with Provider A (D) User A with a pre-existing service relationship with Provider A
attempts communication via the user Interface. The device uses attempts communication via the user Interface. The device uses
the user supplied information (including any credential the user supplied information (including any credential
information) and requests profile enrollment for user A's information) and requests profile enrollment for user A's
profile. Successful enrollment and profile content retrieval profile. Successful enrollment and profile content retrieval
results in services for user A. results in services for user A.
(E) At a different point in time, user B with a service relationship (E) At a different point in time, user B with a service relationship
with Provider B attempts communication via the user Interface. with Provider B attempts communication via the user Interface.
It enrolls and retrieves user B's profile and this results in It enrolls and retrieves user B's profile and this results in
services for user B. services for user B.
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Section 5.3.1). The data can also be "discovered" using the Section 5.3.1). The data can also be "discovered" using the
procedures specified by this framework. The "discovered" data can procedures specified by this framework. The "discovered" data can
be retained across device resets (but not across factory resets) be retained across device resets (but not across factory resets)
and such data is referred to as "cached". Thus, data can be and such data is referred to as "cached". Thus, data can be
configured, discovered or cached. The following requirements configured, discovered or cached. The following requirements
apply. apply.
* If the device is configured with a specific domain name (for * If the device is configured with a specific domain name (for
the local network provider or device provider), it MUST NOT the local network provider or device provider), it MUST NOT
attempt "discovery" of the domain name. This is the case when attempt "discovery" of the domain name. This is the case when
the device is pre-configured (e.g., via a UI) to be managed by the device is pre-configured (e.g., via a user interface) to be
specific entities. managed by specific entities.
* The device MUST only use data associated with the provider's * The device MUST only use data associated with the provider's
domain in an enrollment request. As an example, when the domain in an enrollment request. As an example, when the
device is requesting a local-network profile in the domain device is requesting a local-network profile in the domain
'example.net', it cannot present a user AoR associated with the 'example.net', it cannot present a user AoR associated with the
local domain 'example.com'. local domain 'example.com'.
* The device SHOULD adhere to the following order of data usage: * The device SHOULD adhere to the following order of data usage:
configured, cached and discovered. An exception is when the configured, cached and discovered. An exception is when the
device is explicitly configured to use a different order. device is explicitly configured to use a different order.
Upon failure to obtain the profile using any methods specified in Upon failure to obtain the profile using any methods specified in
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in the Request-URI (the same way it would handle any other in the Request-URI (the same way it would handle any other
SUBSCRIBE message). The authoritative proxy is required to SUBSCRIBE message). The authoritative proxy is required to
examine the request (e.g., event package) and transmit it to a PDS examine the request (e.g., event package) and transmit it to a PDS
capable of addressing the profile enrollment request. capable of addressing the profile enrollment request.
A PDS receiving the enrollment request SHOULD respond to the A PDS receiving the enrollment request SHOULD respond to the
request, or proxy it to a PDS that can respond. An exception is request, or proxy it to a PDS that can respond. An exception is
when a policy prevents a response (e.g., recognition of a DoS when a policy prevents a response (e.g., recognition of a DoS
attack, an invalid device, etc.). The PDS then verifies the attack, an invalid device, etc.). The PDS then verifies the
identity presented in the request and performs any necessary identity presented in the request and performs any necessary
authentication. Once authentication is successful, the PDS MAY authentication. Once authentication is successful, the PDS MUST
admit or reject the enrollment request, based on applicable either admit or reject the enrollment request, based on applicable
authorization policies. A PDS admitting the enrollment request authorization policies. A PDS admitting the enrollment request
indicates it via a 2xx-class response, as specified in [RFC3265]. indicates it via a 2xx-class response, as specified in [RFC3265].
Refer to Section 6.6 and Section 5.2 for more information on Refer to Section 6.6 and Section 5.2 for more information on
subscription request handling and security requirements, subscription request handling and security requirements,
respectively. respectively.
Enrollment request acceptance Enrollment request acceptance
A PDS that admits the enrollment request verifies applicable A PDS that admits the enrollment request verifies applicable
policies, identifies the requested profile data and prepares a SIP policies, identifies the requested profile data and prepares a SIP
NOTIFY message to the device. Such a notification can either NOTIFY message to the device. Such a notification can either
contain the profile data or contain content indirection contain the profile data or contain content indirection
information that results in the device performing profile content information that results in the device performing profile content
retrieval. The PDS then transmits the prepared SIP notification. retrieval. The PDS then transmits the prepared SIP notification.
When the device successfully receives and accepts the SIP When the device successfully receives and accepts the SIP
notification, profile enrollment is complete. notification, profile enrollment is complete.
When it receives the SIP NOTIFY message, indicating successful When it receives the SIP NOTIFY message, indicating successful
profile enrollment, the device MUST make the new profile effective profile enrollment, the device SHOULD make the new profile
within the specified timeframe, as described in Section 6.2. effective within the specified time frame, as described in
Section 6.2. The exception is when the profile data is delivered
via content indirection, and the device cannot obtain the profile
data within the specified time frame.
Once profile enrollment is successful, the PDS MUST consider the Once profile enrollment is successful, the PDS MUST consider the
device enrolled for the specific profile, for the duration of the device enrolled for the specific profile, for the duration of the
subscription. subscription.
5.1.2. Content Retrieval 5.1.2. Content Retrieval
A successful profile enrollment leads to an initial SIP notification, A successful profile enrollment leads to an initial SIP notification,
and may result in subsequent change notifications. Each of these and may result in subsequent change notifications. Each of these
notifications can either contain profile data, or content indirection notifications can either contain profile data, or content indirection
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specified in [RFC4122]. The following requirements apply: specified in [RFC4122]. The following requirements apply:
o When the device has a non-alterable MAC address it SHOULD use o When the device has a non-alterable MAC address it SHOULD use
version 1 UUID representation with the timestamp and clock version 1 UUID representation with the timestamp and clock
sequence bits set to a value of '0'. This will allow for easy sequence bits set to a value of '0'. This will allow for easy
recognition, and uniqueness of MAC address based UUIDs. An recognition, and uniqueness of MAC address based UUIDs. An
exception is the case where the device supports independent device exception is the case where the device supports independent device
configuration for more than one SIP UA. An example would be configuration for more than one SIP UA. An example would be
multiple SIP UAs on the same platform. multiple SIP UAs on the same platform.
o If the device cannot use a non-alterable device identifier, it o If the device cannot use a non-alterable device identifier, it
SHOULD use an alternative non-alterable device identifier. For SHOULD use an alternative non-alterable device identifier. For
example, the International Manufacturer's Equipment Identifier example, the International Mobile Equipment Identity (IMEI) for
(IMEI) for mobile devices. mobile devices.
o If the device cannot use a non-alterable MAC Address, it MUST be o If the device cannot use a non-alterable MAC Address, it MUST be
use the same approach as defining a user agent Instance ID in use the same approach as defining a user agent Instance ID in
[I-D.ietf-sip-outbound]. [I-D.ietf-sip-outbound].
o Note: when the URN is used as the user part of the Request URI, it o Note: when the URN is used as the user part of the Request URI, it
MUST be URL escaped since the colon (":") is not a legal character MUST be URL escaped since the colon (":") is not a legal character
in the user part of an addr-spec ([RFC4122]), and must be escaped. in the user part of an addr-spec ([RFC4122]), and must be escaped.
For example, the instance ID: For example, the instance ID:
urn:uuid:f81d4fae-7ced-11d0-a765-00a0c91e6bf6@example.com urn:uuid:f81d4fae-7ced-11d0-a765-00a0c91e6bf6@example.com
would be escaped to look as follows in a URI: would be escaped to look as follows in a URI:
sip:urn%3auuid%3af81d4fae-7ced-11d0-a765-00a0c91e6bf6@ sip:urn%3auuid%3af81d4fae-7ced-11d0-a765-00a0c91e6bf6@
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Profile data can contain sensitive information that needs to be Profile data can contain sensitive information that needs to be
secured, such as identities and credentials. Security involves secured, such as identities and credentials. Security involves
authentication, message integrity and privacy. Authentication is the authentication, message integrity and privacy. Authentication is the
process by which you verify that an entity is who it claims to be, process by which you verify that an entity is who it claims to be,
such as a user AoR presented during profile enrollment. Message such as a user AoR presented during profile enrollment. Message
integrity provides the assurance that the message contents integrity provides the assurance that the message contents
transmitted between two entities, such as between the PDS and the transmitted between two entities, such as between the PDS and the
device, has not been modified during transit. Privacy ensures that device, has not been modified during transit. Privacy ensures that
the message contents have not been subjected to monitoring by the message contents have not been subjected to monitoring by
unwanted elements during transit. For profile data that contains unwanted elements during transit. Authentication and message
sensitive information, authentication and message integrity are integrity are required to ensure that the profile contents were
required to ensure that the profile contents were received by a valid received by a valid entity, from a valid source, and without any
entity, from a valid source, and without any modifications during modifications during transit. For profiles that contain sensitive
transit. For profiles that contain sensitive data, privacy is also data, privacy is also required.
required.
For an overview of potential security threats, refer to Section 9. For an overview of potential security threats, refer to Section 9.
For information on how the device can be configured with identities For information on how the device can be configured with identities
and credentials, refer to Section 5.3.1. The following subsections and credentials, refer to Section 5.3.1. The following subsections
provide the security requirements associated with each profile provide the security requirements associated with each profile
delivery stage, and applies to each of profile types specified by delivery stage, and applies to each of profile types specified by
this framework. this framework.
5.2.1. Securing Profile Enrollment 5.2.1. Securing Profile Enrollment
Profile enrollment may result in sensitive profile data. In such Profile enrollment may result in sensitive profile data. In such
cases, the PDS MUST authenticate the device, except during the cases, the PDS MUST authenticate the device, except during the
bootstrapping scenario when the device does not have existing bootstrapping scenario when the device does not have existing
credentials. Additionally, the device MUST authenticate the PDS to credentials (see Section 5.3.1 for more information on
ensure that it is obtaining sensitive profile data from a valid PDS, bootstrapping). Additionally, the device MUST authenticate the PDS
except in the bootstrapping scenario. to ensure that it is obtaining sensitive profile data from a valid
PDS, except in the bootstrapping scenario.
To authenticate a device that has been configured with identities and To authenticate a device that has been configured with identities and
credentials as specified in Section 5.3.1 and support profiles credentials as specified in Section 5.3.1 and support profiles
containing sensitive profile data (refer to Section 5.3.4), devices containing sensitive profile data (refer to Section 5.3.4), devices
and PDSs MUST support Digest Authentication as specified in and PDSs MUST support Digest Authentication as specified in
[RFC3261]. Future enhancements may provide other authentication [RFC3261]. Future enhancements may provide other authentication
methods such as authentication using X.509 certificates. For the methods such as authentication using X.509 certificates. For the
device to authenticate the PDS, the device MUST mutually authenticate device to authenticate the PDS, the device MUST mutually authenticate
with the PDS during digest authentication (device challenges the with the PDS during digest authentication (device challenges the PDS,
client that responds with the Authorization header). Transmission of which responds with the Authorization header). Transmission of
sensitive profile data also requires message integrity. This can be sensitive profile data also requires message integrity. This can be
provided by configuring the device with a SIPS URI resulting in TLS accomplished by configuring the device with, or by ensuring that the
establishment ([RFC4346]). TLS also prevents offline dictionary discovery process during profile enrollment provides, a SIPS URI
attacks when digest authentication is used. Thus, in the absence of resulting in TLS establishment ([RFC4346]). TLS also prevents
TLS, the device MUST NOT respond to any authentication challenges. offline dictionary attacks when digest authentication is used. Thus,
It is to be noted that the digest credentials used for obtaining in the absence of TLS, the device MUST NOT respond to any
profile data via this framework may, or may not, be the same as that authentication challenges. It is to be noted that the digest
used for SIP registration (see Section 5.3.1). 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).
When the PDS challenges a profile enrollment request, and it fails, When the PDS challenges a profile enrollment request, and it fails,
the PDS MAY refuse enrollment or provide profile data without the the PDS MAY refuse enrollment or provide profile data without the
user-specific information (e.g., to bootstrap a device that may have user-specific information (e.g., to bootstrap a device as indicated
misplaced credentials). If the device challenges, but fails to in Section 5.3.1). If the device challenges, but fails to
authenticate the PDS, it MUST reject the initial notification and authenticate the PDS, it MUST reject the initial notification and
retry the profile enrollment process. If the device is configured retry the profile enrollment process. If the device is configured
with a SIPS URI and TLS establishment fails because the next-hop SIP with, or discovers, a SIPS URI but TLS establishment fails because
entity does not support TLS, the device SHOULD attempt other resolved the next-hop SIP entity does not support TLS, the device SHOULD
next-hop SIP entities. When the device establishes TLS with the attempt other resolved next-hop SIP entities. When the device
next-hop entity, the device MUST use the procedures specified in establishes TLS with the next-hop entity, the device MUST use the
[RFC2818], Section 3.1, for authentication, unless it does not have procedures specified in [RFC2818], Section 3.1, for authentication,
any configured information to verify the same (e.g., prior to unless it does not have any configured information (e.g., CA
bootstrapping). The 'Server Identity' in this case is always the certificate) to perform authentication (like prior to bootstrapping).
domain of the next-hop SIP entity. If the device attempts The 'Server Identity' for authentication is always the domain of the
validation, and it fails, it MUST reject the intial notification and next-hop SIP entity. If the device attempts validation, and it
retry profile enrollment. In the absence of TLS and a mechanism for fails, it MUST reject the initial notification and retry profile
mutual authentication, the PDS MUST NOT present any sensitive profile enrollment. In the absence of a SIPS URI for the device and a
data in the initial notification, except when the device is being mechanism for mutual authentication, the PDS MUST NOT present any
boostrapped. It MAY still use content indirection to transmit sensitive profile data in the initial notification, except when the
sensitive profile data. device is being bootstrapped. It MAY still use content indirection
to transmit sensitive profile data.
When a device is being provided with bootstrapping profile data When a device is being provided with bootstrapping profile data
containing sensitive information, the PDS SHOULD use the SIP Identity within the notification, and it contains sensitive information, the
header as specified in [RFC4474] within the notification. This helps SIP Identity header SHOULD be used as specified in [RFC4474]. This
with devices that MAY be pre-configured with certificates to validate helps with devices that MAY be pre-configured with certificates to
bootstrapping sources (e.g., list of allowed domain certificates, or validate bootstrapping sources (e.g., list of allowed domain
a list of root CA certificates using PKI). Further, the profile data certificates, or a list of root CA certificates using PKI). When the
may contain the domain certificate used for creating the SIP Identity SIP Identity header is used, the PDS MUST set the host portion of the
header, for devices that are not pre-configured with any information, AoR in the 'From' header to the Provider's domain (the user portion
and can be used to guarantee header and body integrity. It can also is a entity-specific identifier). If the device is capable of
allow the device to present the identity of the PDS to a user for validating the SIP Identity, and it fails, it MUST reject
verification (if such an interface exists). When the SIP Identity bootstrapping profile data.
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). If the device is capable of validating the SIP
Identity, and it fails, it MUST reject bootstrapping profile data.
5.2.2. Securing Content Retrieval 5.2.2. Securing Content Retrieval
Initial or change notifications following a successful enrollment can Initial or change notifications following a successful enrollment can
provide a device with the requested profile data, or use content provide a device with the requested profile data, or use content
indirection to direct it to a PCC that can provide the profile data. indirection to direct it to a PCC that can provide the profile data.
This document specifies HTTP and HTTPS as content retrieval This document specifies HTTP and HTTPS as content retrieval
protocols. protocols.
If the profile is provided via content indirection and contains If the profile is provided via content indirection and contains
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5.2.3. Securing Change Notification 5.2.3. Securing Change Notification
If the device requested enrollment via a SIP subscription with a non- If the device requested enrollment via a SIP subscription with a non-
zero 'Expires' parameter, it can also result in change notifications zero 'Expires' parameter, it can also result in change notifications
for the duration of the subscription. For change notifications for the duration of the subscription. For change notifications
containing sensitive profile data, this framework RECOMMENDS the use containing sensitive profile data, this framework RECOMMENDS the use
of the SIP Identity header as specified in [RFC4474]. When the SIP 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 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 in the 'From' header to the Provider's domain (the user portion is a
entity-specific identifier). This provides header and body integrity entity-specific identifier). This provides header and body integrity
as well. However, for sensitive profile data that needs privacy and as well. However, for sensitive profile data requiring privacy, if
is not being transmitted over a channel such as TLS, the PDS MUST use the contact URI to which the NOTIFY request is to be sent is not
content indirection. Additionally, the PDS MUST also use content SIPS, the PDS MUST use content indirection. Additionally, the PDS
indirection for notifications containing sensitive profile data, when MUST also use content indirection for notifications containing
the profile enrollment was not authenticated. sensitive profile data, when the profile enrollment was not
authenticated.
5.3. Additional Considerations 5.3. Additional Considerations
This section provides additional considerations such as details on This section provides additional considerations such as details on
how a device obtains identities and credentials, backoff and retry how a device obtains identities and credentials, backoff and retry
methods, guidelines on profile data and additional profile types. methods, guidelines on profile data and additional profile types.
5.3.1. Identities and Credentials 5.3.1. Bootstrapping Identities and Credentials
When requesting a profile the device can provide an identity such as When requesting a profile the device can provide an identity (i.e., a
a user AoR. To do so, the device needs to be configured. This can user AoR), and contain associated credentials for authentication. To
be accomplished in one of the following ways: do so, the device needs to obtain this information via bootstrapping.
This can be accomplished in one of the following ways:
Pre-configuration Pre-configuration
The device may be pre-configured with identities and associated The device may be pre-configured with identities and associated
credentials, such as a user AoR and digest password. credentials, such as a user AoR and digest password.
Out-of-band methods Out-of-band methods
A device or Provider may provide hardware- or software-based A device or Provider may provide hardware- or software-based
credentials such as SIM cards or USB drives. credentials such as SIM cards or Universal Serial Bus (USB)
drives.
End-user interface End-user interface
The end-user may be provided with the necessary identities and The end-user may be provided with the necessary identities and
credentials. The end-user can then configure the device (using a credentials. The end-user can then configure the device (using a
user interface), or present when required (e.g., IM login screen). user interface), or present when required (e.g., IM login screen).
Using this framework Using this framework
When a device is initialized, even if it has no pre-configured When a device is initialized, even if it has no pre-configured
information, it can request the local-network and device profiles. information, it can request the local-network and device profiles.
In such a case the device profile can provide one of the following For purposes of bootstrapping, this framework recommends that the
to bootstap the device: device profile provide one of the following to bootstrap the
device:
* Profile data that allows the end-user to communicate by non-SIP * Profile data that allows the end-user to communicate with the
means with the device provider or SIP service provider. The device provider or SIP service provider using non-SIP methods.
provider can then use any applicable method (e.g., web portal) For example, the profile data can direct the end-user to a web
to provide the user AoR. 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 * Content indirection information to a PCC that can provide
identities and credentials. As an example, consider a device identities and credentials. As an example, consider a device
that has a X.509 certificate that can be authenticated by the that has a X.509 certificate that can be authenticated by the
PCC. In such a case, the PCC can use HTTPS to provide PCC. In such a case, the PCC can use HTTPS to provide
identities and associated credentials. identities and associated credentials.
* Profile data containing identities and credentials that can be * Profile data containing identities and credentials that can be
used to bootstrap the device. This can be used in cases where used to bootstrap the device (see Section 5.3.4 for profile
the device is initialized for the first time, or after a data recommendations). This can be used in cases where the
factory reset. This can be considered only in cases where the device is initialized for the first time, or after a factory
device is initialized in the Provider's network, for obvious reset. This can be considered only in cases where the device
security reasons. is initialized in the Provider's network, for obvious security
reasons.
Additionally, AoRs are typically known by PDSs that serve the domain Additionally, AoRs are typically known by PDSs that serve the domain
indicated by the AoR. Thus, devices can only present the configured indicated by the AoR. Thus, devices can only present the configured
AoRs in the respective domains. An exception is the use of federated 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 identities. This allows a device to use a user's AoR in multiple
domains. Further even within the same domain, the device's domain 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 proxy and the PDS may be in two different realms, and as such may be
associated with different credentials for digest authentication. In associated with different credentials for digest authentication. In
such cases, multiple credentials may be configured, and associated such cases, multiple credentials may be configured, and associated
with the realms in which they are to be used. This framework with the realms in which they are to be used. This framework
specifies only digest authentication and the device is not expected specifies only digest authentication for profile enrollment and the
to contain any other credentials. Future enhancements can specify device is not expected to contain any other credentials. For profile
additional identities and credentials such as X.509 certificates. retrieval using content indirection, the device will need to support
additional credentials such as X.509 certificates (for TLS). Future
enhancements can specify additional credential types for profile
enrollment and retrieval.
5.3.2. Profile Enrollment Request Attempt 5.3.2. Profile Enrollment Request Attempt
A state diagram representing a device requesting any specific profile A state diagram representing a device requesting any specific profile
defined by this framework is shown in Figure 6. defined by this framework is shown in Figure 6.
+------------+ +------------+
| Initialize | | Initialize |
+-----+------+ +-----+------+
| |
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network infrastructure elements e.g., SIP servers). network infrastructure elements e.g., SIP servers).
5.3.4. Profile Data 5.3.4. Profile Data
This framework does not specify the contents for any profile type. This framework does not specify the contents for any profile type.
Follow-on standardization activities are expected to address profile Follow-on standardization activities are expected to address profile
contents. However, the framework provides the following requirements contents. However, the framework provides the following requirements
and recommendations for profile data definitions: and recommendations for profile data definitions:
o The device profile type SHOULD specify parameters to configure the o The device profile type SHOULD specify parameters to configure the
identities and credentials. These parameters may be optional or identities and credentials for use in scenarios such as
mandatory and will be used for dynamically configuring devices bootstrapping (see Section 5.3.1) and run-time modifications to
that initialize in a network without any pre-configuration. 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.
o Each profile MUST clearly identify if it may contain any sensitive o Each profile MUST clearly identify if it may contain any sensitive
data. Such profiles MUST also identify the data elements that are data. Such profiles MUST also identify the data elements that are
considered sensitive, i.e., data that cannot be compromised. As considered sensitive, i.e., data that cannot be compromised. As
an example, a device profile definition may identify itself as an example, a device profile definition may identify itself as
containing sensitive data and indicate data such as device containing sensitive data and indicate data such as device
credentials to be sensitive. credentials to be sensitive.
o When the device receives multiple profiles, the contents of each o When the device receives multiple profiles, the contents of each
profile type SHOULD only contain data relevant to the entity it profile type SHOULD only contain data relevant to the entity it
represents. As an example, consider a device that obtains all the represents. As an example, consider a device that obtains all the
defined profiles. Information pertaining to the local network is defined profiles. Information pertaining to the local network is
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Notifier is configured to accept such requests. Notifier is configured to accept such requests.
The Notifier MAY also authenticate SUBSCRIBE messages even if the The Notifier MAY also authenticate SUBSCRIBE messages even if the
NOTIFY is expected to only contain a pointer to profile data. NOTIFY is expected to only contain a pointer to profile data.
Securing data sent via Content Indirection is covered in Section 9. Securing data sent via Content Indirection is covered in Section 9.
If the profile type indicated in the "profile-type" Event header If the profile type indicated in the "profile-type" Event header
parameter is unavailable or the Notifier is configured not to provide parameter is unavailable or the Notifier is configured not to provide
it, the Notifier SHOULD return a 404 response to the SUBSCRIBE it, the Notifier SHOULD return a 404 response to the SUBSCRIBE
request. If the specific user or device is unknown, the Notifier MAY request. If the specific user or device is unknown, the Notifier MAY
either accept or reject the subscription with a 403 response. accept the subscription, or else it may reject the subscription (with
a 403 response).
6.7. Notifier Generation of NOTIFY Requests 6.7. Notifier Generation of NOTIFY Requests
As specified in [RFC3265], the Notifier MUST always send a NOTIFY As specified in [RFC3265], the Notifier MUST always send a NOTIFY
request upon accepting a subscription. If the device or user is request upon accepting a subscription. If the device or user is
unknown and the Notifier chooses to accept the subscription, the unknown and the Notifier chooses to accept the subscription, the
Notifier MAY either respond with profile data (e.g., default profile Notifier MAY either respond with profile data (e.g., default profile
data) or provide no profile information (i.e., empty NOTIFY). data) or provide no profile information (i.e., empty NOTIFY).
If the identity indicated in the SUBSCRIBE request (From header) is a If the identity indicated in the SUBSCRIBE request (From header) is a
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6.8. Subscriber Processing of NOTIFY Requests 6.8. Subscriber Processing of NOTIFY Requests
A Subscriber to this event package MUST adhere to the NOTIFY request A Subscriber to this event package MUST adhere to the NOTIFY request
processing behavior specified in [RFC3265]. If the Notifier processing behavior specified in [RFC3265]. If the Notifier
indicated an effective time (using the "effective-by" Event Header indicated an effective time (using the "effective-by" Event Header
parameter), the Subscriber SHOULD attempt to make the profiles parameter), the Subscriber SHOULD attempt to make the profiles
effective within the specified time. Exceptions include deployments effective within the specified time. Exceptions include deployments
that prohibit such behavior in certain cases (e.g., emergency that prohibit such behavior in certain cases (e.g., emergency
sessions are in progress). When profile data cannot be applied sessions are in progress). When profile data cannot be applied
within the recommended timeframe and this affects device behavior, within the recommended time frame and this affects device behavior,
any actions to be taken SHOULD be defined by the profile data any actions to be taken SHOULD be defined by the profile data
definitions. By default, the Subscriber is RECOMMENDED to make the definitions. By default, the Subscriber is RECOMMENDED to make the
profiles effective as soon as possible. profiles effective as soon as possible.
When accepting content indirection, the Subscriber MUST always When accepting content indirection, the Subscriber MUST always
support "http:" or "https:" and be prepared to accept NOTIFY messages support "http:" or "https:" and be prepared to accept NOTIFY messages
with those URI schemes. If the Subscriber wishes to support with those URI schemes. If the Subscriber wishes to support
alternative URI schemes they MUST each be indicated in the "schemes" alternative URI schemes they MUST each be indicated in the "schemes"
Contact header field parameter as defined in [RFC4483]. The Contact header field parameter as defined in [RFC4483]. The
Subscriber MUST also be prepared to receive a NOTIFY request with no Subscriber MUST also be prepared to receive a NOTIFY request with no
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(XRes) (XRes)
the HTTP server responds to the request via a HTTP response the HTTP server responds to the request via a HTTP response
containing the profile contents containing the profile contents
7.2. Example 2: Device obtaining change notification 7.2. Example 2: Device obtaining change notification
The following example illustrates the case where a user (X) is The following example illustrates the case where a user (X) is
simultaneously accessing services via two different devices (e.g., simultaneously accessing services via two different devices (e.g.,
Multimedia entities on a PC and PDA) and has access to a user Multimedia entities on a PC and PDA) and has access to a user
Interface (UI) that allows for changes to the user profile. interface that allows for changes to the user profile.
The following are assumed for this example: The following are assumed for this example:
o The devices (A & B) obtain the necessary profiles from the same o The devices (A & B) obtain the necessary profiles from the same
SIP Service Provider. SIP Service Provider.
o The SIP Service Provider also provides a user Interface (UI) that o The SIP Service Provider also provides a user interface that
allows the user to change preferences that impact the user allows the user to change preferences that impact the user
profile. profile.
The flow diagram and an explanation of the messages follow. The flow diagram and an explanation of the messages follow.
o Note: The example only shows retrieval of user X's profile, but it o Note: The example only shows retrieval of user X's profile, but it
may request and retrieve other profiles (e.g., local-network, may request and retrieve other profiles (e.g., local-network,
Device). Device).
----- ----- ----- -----
|User |_________| UI* | * = User Interface |User |_________| UI* | * = User Interface
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| | | | | |
| (B-RX)|<= Retrieves User X's profile=>| | (B-RX)|<= Retrieves User X's profile=>|
| | | | | |
(A-EX) Device A discovers, enrolls and obtains notification related (A-EX) Device A discovers, enrolls and obtains notification related
to user X's profile. to user X's profile.
(A-RX) Device A retrieves user X's profile. (A-RX) Device A retrieves user X's profile.
(B-EX) Device B discovers, enrolls and obtains notification related (B-EX) Device B discovers, enrolls and obtains notification related
to user X's profile. to user X's profile.
(B-RX) Device B retrieves user X's profile. (B-RX) Device B retrieves user X's profile.
(HPut) Changes affected by the user via the user Interface (UI) are (HPut) Changes affected by the user via the user interface are
uploaded to the HTTP Server. uploaded to the HTTP Server.
* Note: The UI itself can act as a device and subscribe to user * Note: The UI itself can act as a device and subscribe to user
X's profile. This is not the case in the example shown. X's profile. This is not the case in the example shown.
(HRes) Changes are accepted by the HTTP server. (HRes) Changes are accepted by the HTTP server.
(A-NT) PDS transmits a NOTIFY message to device A indicating the (A-NT) PDS transmits a NOTIFY message to device A indicating the
changed profile. A sample message is shown below: changed profile. A sample message is shown below:
Note: Some of the fields (e.g., Via) are continued on a Note: Some of the fields (e.g., Via) are continued on a
separate line due to format constraints of this document. separate line due to format constraints of this document.
NOTIFY sip:userX@192.0.2.44 SIP/2.0 NOTIFY sip:userX@192.0.2.44 SIP/2.0
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the Request-URI and event header contents to route it to a PDS (via the Request-URI and event header contents to route it to a PDS (via
other SIP proxies, if required). other SIP proxies, if required).
When a PDS receives the enrollment request, it can either challenge When a PDS receives the enrollment request, it can either challenge
any contained identity or admit the enrollment. Authorization rules any contained identity or admit the enrollment. Authorization rules
then decide if the enrollment gets accepted. If accepted, the PDS then decide if the enrollment gets accepted. If accepted, the PDS
sends an initial notification that contains either the profile data, sends an initial notification that contains either the profile data,
or content indirection information. The profile data can contain or content indirection information. The profile data can contain
generic profile data (common across multiple devices) or information generic profile data (common across multiple devices) or information
specific to an entity (such as the device or a user). If specific to specific to an entity (such as the device or a user). If specific to
an entity, it and may contain sensitive information such as an entity, it may contain sensitive information such as credentials.
credentials. Compromise of sensitive data can lead to threats such Compromise of sensitive data can lead to threats such as
as impersonation attacks (establishing rogue sessions), theft of impersonation attacks (establishing rogue sessions), theft of service
service (if services are obtainable), and zombie attacks. Even if (if services are obtainable), and zombie attacks. It is important
the profile data is provided using content indirection, PCC for the device to ensure the authenticity of the PNC and the PCC
information within the notification can lead to threats such as since impersonation of the SIP service provider can lead to Denial of
denial of service attacks (rogue devices bombard the PCC with Service and Man-in-the-Middle attacks.
requests for a specific profile) and attempts to modify erroneous
data onto the PCC (since the location and format may be known). It
is also important for the device to ensure the authenticity of the
PNC 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 Profile content retrieval allows a device to retrieve profile data
via content indirection from a PCC. This communication is via content indirection from a PCC. This communication is
accomplished using one of many profile delivery protocols or accomplished using one of many profile delivery protocols or
frameworks, such as HTTP or HTTPS as specified in this document. frameworks, such as HTTP or HTTPS as specified in this document.
However, since the profile data returned is subject to the same However, since the profile data returned is subject to the same
considerations as that sent via profile notification, similar threats considerations as that sent via profile notification, similar threats
exist. Thus, for the delivery of any sensitive profile data, 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 authentication of the entity requesting profile data is required. It
is also important for the requesting entity to authenticate the PDS is also important for the requesting entity to authenticate the
and ensure that the sensitive profile data is protected via message profile source via content indirection, and ensure that the sensitive
integrity. For sensitive data that should not be subject to profile data is protected via message integrity. For sensitive data
snooping, privacy is also required. that should not be subject to snooping, privacy is also required.
The following sub-sections highlight the security considerations that The following sub-sections highlight the security considerations that
are specific to each profile type. are specific to each profile type.
9.1. Local-network profile 9.1. Local-network profile
A local network may or may not (e.g., home router) support local- A local network may or may not (e.g., home router) support local-
network profiles as specified in this framework. Even if supported, network profiles as specified in this framework. Even if supported,
the PDS may only be configured with a generic local-network profile the PDS may only be configured with a generic local-network profile
that is provided to every device that requests the local-network that is provided to every device that requests the local-network
profile. Such a PDS may not implement any authentication profile. Such a PDS may not implement any authentication
requirements or TLS. requirements or TLS.
Alternatively, certain deployments may require the entities - device Alternatively, certain deployments may require the entities - device
and the PDS - to authenticate each other prior to succesful profile and the PDS - to authenticate each other prior to successful profile
enrollment. Such networks may pre-configure user identities to the enrollment. Such networks may pre-configure user identities to the
devices and allow user-specific local-network profiles. In such devices and allow user-specific local-network profiles. In such
networks the PDS will support digest, and the devices are configured networks the PDS will support digest, and the devices are configured
with user identities and credentials as specified in Section 5.3.1. with user identities and credentials as specified in Section 5.3.1.
If sensitive profile data is being transmitted, the user identity is If sensitive profile data is being transmitted, the user identity is
a SIPS URI that results in TLS with the next-hop (which 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 authenticated), and digest authentication is used by the PDS and the
device. device.
This framework supports both use cases and any variations in-between. This framework supports both use cases and any variations in-between.
However, devices obtaining local-network profiles from an However, devices obtaining local-network profiles from an
unauthenticated PDS are cautioned against potential MiM or PDS unauthenticated PDS are cautioned against potential Man-in-the-Middle
impersonation attacks. This framework requires that a device reject or PDS impersonation attacks. This framework requires that a device
sensitive data, such as credentials, from unauthenticated local- reject sensitive data, such as credentials, from unauthenticated
network sources. It also prohibits devices from responding to local-network sources. It also prohibits devices from responding to
authentication challenges in the absence of TLS. Responding to authentication challenges in the absence TLS on all hops as a result
unauthenticated challenges allows for dictionary attacks that can of using a SIPS URI. Responding to unauthenticated challenges allows
reveal weak passwords. for dictionary attacks that can reveal weak passwords. The only
exception to accepting such sensitive data without authentication of
the PDS is in the case of bootstrapping (see Section 5.3.1). In the
case of bootstrapping, the methods employed need to be aware of
potential security threats such as impersonation.
The use of SIP Identity is useful for the device to validate The use of SIP Identity is useful for the device to validate
notifications in the absence of a secure channel such as TLS. In notifications in the absence of a secure channel such as TLS when a
such cases the device can validate the SIP Identity header to verify SIPS URI is used. In such cases the device can validate the SIP
the source of the local-network profile. However, the presence of Identity header to verify the source of the profile notification, and
the header does not guarantee the validity of the data. It verifies the source of the profile data when content indirection is not used.
the source and confirms data integrity, but the data obtained from an However, the presence of the header does not guarantee the validity
undesired source may still be invalid, e.g., invalid outbound proxy of the data. It verifies the source and confirms data integrity, but
information, resulting in Denial of Service. Thus, devices the data obtained from an undesired source may still be invalid,
requesting the local-network profile from unknown networks need to be e.g., invalid outbound proxy information, resulting in Denial of
prepared to discard information that prevent retrieval of other, Service. Thus, devices requesting the local-network profile from
required, profiles. unknown networks need to be prepared to discard information that
prevent retrieval of other, required, profiles.
9.2. Device profile 9.2. Device profile
Device profiles deal with device-specific configuration. They may be Device profiles deal with device-specific configuration. They may be
provided to unknown devices that are attempting to obtaining profiles provided to unknown devices that are attempting to obtaining profiles
for purposes such as trials, self-subscription (not to be confused for purposes such as trials, self-subscription (not to be confused
with [RFC3265]) and emergency services ([I-D.ietf-ecrit-phonebcp]). with [RFC3265]) and emergency services ([I-D.ietf-ecrit-phonebcp]).
This framework allows for the device profile to be used for This framework allows for the device profile to be used for
bootstrapping a device. Such boostrapping profile data may contain bootstrapping a device. Such bootstrapping profile data may contain
enough information to connect to a Provider. For example, it may enough information to connect to a Provider. For example, it may
enable the device to communicate with a device provider, allowing for enable the device to communicate with a device provider, allowing for
trial or self-subscription services via visual or audio interfaces trial or self-subscription services via visual or audio interfaces
(e.g., interactive voice response), or customer service (e.g., interactive voice response), or customer service
representatives. The profile data may also allow the device a choice representatives. The profile data may also allow the device a choice
of device providers and allow the end-user to choose one. The of device providers and allow the end-user to choose one. The
profile data may also contain identities and credentials (temporary profile data may also contain identities and credentials (temporary
or long-term) that can be used to obtain further profile data from or long-term) that can be used to obtain further profile data from
the network. If it contains such sensitive data, the framework the network. This framework recommends the use of the SIP Identity
recommends the use of the SIP Identity header by the PDS. However, header by the PDS. However, to be able to validate the SIP Identity
to be able to validate the header, the device needs to be pre- header, the device needs to be pre-configured with the knowledge of
configured with the knowledge of allowable domains or certificates allowable domains or certificates for validation (e.g., using PKI).
for validation (e.g., using PKI). If not, the device can still If not, the device can still guarantee header and body integrity if
guarantee header and body integrity if the profile data contains the the profile data contains the domain certificate (but the data can
domain certificate (but the data can still be invalid or malicious). still be invalid or malicious). In such cases, devices supporting
In such cases, devices supporting user interfaces may obtain user interfaces may obtain confirmation from the user trying to
confirmation from the user trying to boostrap the device (confirming bootstrap the device (confirming header and body integrity).
header and body integrity). However, when the SIP Identity header is However, when the SIP Identity header is not present, or the device
not present, or the device is not capable of validating it, the is not capable of validating it, the bootstrapping data is
bootstrapping data is unauthenticated and obtained without any unauthenticated and obtained without any integrity protection. Such
integrity protection. Such bootstrapping data, however, may contain bootstrapping data, however, may contain only temporary credentials
only temporary credentials (SIPS URI and digest credentials) that can (SIPS URI and digest credentials) that can be used to reconnect to
be used to reconnect to the network to ensure message integrity and the network to ensure message integrity and privacy prior to
privacy prior to obtaining long-term credentials. It is to be noted obtaining long-term credentials. It is to be noted that such devices
that such devices are at the mercy of the network they request the are at the mercy of the network they request the device profile from.
device profile from. If they are initialized in a rogue network, or If they are initialized in a rogue network, or get hijacked by a
get hijacked by a rogue PDS, the end-user may be left without desired rogue PDS, the end-user may be left without desired device operation
device operation or, worse, unwanted operation. To mitigate such or, worse, unwanted operation. To mitigate such factors the device
factors the device provider may communicate temporary credentials provider may communicate temporary credentials (e.g., passwords that
(PINs that can be entered via an interface) or permanent credentials can be entered via an interface) or permanent credentials (e.g., a
(e.g., a USB device) to the end-user for connectivity. If such USB device) to the end-user for connectivity. If such methods are
methods are used then large-entropy credentials MUST be used, or used, those credentials MUST be quickly replaced by large-entropy
quickly replaced with such, to minimize the impact of dictionary credentials, to minimize the impact of dictionary attacks. Future
attacks. Future enhancements to this framework may specify device enhancements to this framework may specify device capabilities that
capabilities that allow for authentication without any pre- allow for authentication without any provider specific configuration
configuration (e.g., X.509 certificates using PKI). Alternatively, a (e.g., X.509 certificates using PKI can allow for authentication by
PDS can use secure content indirection mechanisms such as HTTPS to any provider with access to the CA certificate). Alternatively, the
provide the bootstrapping data. 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 Once a device is associated with a device provider the device profile
is vital to device operation. This is because the device profile can is vital to device operation. This is because the device profile can
contain important operational information such as users that are to contain important operational information such as users that are to
be allowed access (white-list or black-list), user credentials (if be allowed access (white-list or black-list), user credentials (if
required) and other sensitive information. Thus, it is necessary to required) and other sensitive information. Thus, it is necessary to
ensure that any device profile containing sensitive information is ensure that any device profile containing sensitive information is
obtained via an authenticated source, with integrity protection, and obtained via an authenticated source, with integrity protection, and
delivered to an authenticated device. For sensitive information such delivered to an authenticated device. For sensitive information such
as credentials, privacy is also required. The framework requires as credentials, privacy is also required. The framework requires
that devices obtain sensitive information only from authenticated that devices obtain sensitive information only from authenticated
entities except while it is being bootstrapped. In cases where entities except while it is being bootstrapped. In cases where
privacy needs to be mandated for notifications, the device provider privacy needs to be mandated for notifications, the device provider
can configure the device with a SIPS URI, to be used as the can configure the device with a SIPS URI, to be used as the
subscription URI, during profile enrollment. The framework also subscription URI, during profile enrollment. The framework also
requires that a PDS presenting sensitive profile data to use digest requires a PDS presenting sensitive profile data to use digest
authentication. This ensures that the data is delivered to an authentication. This ensures that the data is delivered to an
authenticated entity. Authentication of profile retrieval via authenticated entity. Authentication of profile retrieval via
content indirection for sensitive profiles is via HTTPS. content indirection for sensitive profiles is via HTTPS utilizing
HTTP digest.
9.3. User profile 9.3. User profile
Devices can only request user profiles for users that are known by a Devices can only request user profiles for users that are known by a
SIP service provider. PDSs are required to reject user profile SIP service provider. PDSs are required to reject user profile
enrollment requests for any users that are unknown in the network. enrollment requests for any users that are unknown in the network.
For known user AoRs that are allowed to retrieve profiles, the For known user AoRs that are allowed to retrieve profiles, the
security considerations are similar to that of the device profile security considerations are similar to that of the device profile
(except for bootstrapping). (except for bootstrapping).
skipping to change at page 50, line 48 skipping to change at page 52, line 6
from Counterpath, Alvin Jiang of Engin and Francois Audet from from Counterpath, Alvin Jiang of Engin and Francois Audet from
Nortel. Nortel.
The following SIPPING WG members are thanked for numerous reviews, The following SIPPING WG members are thanked for numerous reviews,
comments and recommendations: John Elwell from Siemens, Donald Lukacs comments and recommendations: John Elwell from Siemens, Donald Lukacs
from Telcordia, Roni Even from Polycom, David Robbins from Verizon, from Telcordia, Roni Even from Polycom, David Robbins from Verizon,
Shida Schubert from NTT Advanced Technology Corporation, and Eugene Shida Schubert from NTT Advanced Technology Corporation, and Eugene
Nechamkin from Broadcom. The editor would also like to extend a Nechamkin from Broadcom. The editor would also like to extend a
special thanks to the comments and recommendations provided by the special thanks to the comments and recommendations provided by the
SIPPING WG, specifically Keith Drage from Lucent (restructuring SIPPING WG, specifically Keith Drage from Lucent (restructuring
proposal) and John Elwell from Siemens. proposal) and John Elwell from Siemens (numerous reviews and
recommendations).
Additionally, appreciation is also due to Peter Koch for expert DNS Additionally, appreciation is also due to Peter Koch for expert DNS
advice. advice.
And finally, sincere appreciation is extended to the chairs (Mary And finally, sincere appreciation is extended to the chairs (Mary
Barnes from Nortel and Gonzalo Camarillo from Ericsson) and the Area Barnes from Nortel and Gonzalo Camarillo from Ericsson) and the Area
Directors (Cullen Jennings from Cisco and Jon Peterson from Neustar) Directors (Cullen Jennings from Cisco and Jon Peterson from Neustar)
for facilitating discussions, reviews and contributions. for facilitating discussions, reviews and contributions.
11. References 11. References
skipping to change at page 52, line 35 skipping to change at page 53, line 43
[I-D.ietf-ecrit-phonebcp] [I-D.ietf-ecrit-phonebcp]
Rosen, B. and J. Polk, "Best Current Practice for Rosen, B. and J. Polk, "Best Current Practice for
Communications Services in support of Emergency Calling", Communications Services in support of Emergency Calling",
draft-ietf-ecrit-phonebcp-02 (work in progress), draft-ietf-ecrit-phonebcp-02 (work in progress),
September 2007. September 2007.
[I-D.ietf-sip-outbound] [I-D.ietf-sip-outbound]
Jennings, C. and R. Mahy, "Managing Client Initiated Jennings, C. and R. Mahy, "Managing Client Initiated
Connections in the Session Initiation Protocol (SIP)", Connections in the Session Initiation Protocol (SIP)",
draft-ietf-sip-outbound-10 (work in progress), July 2007. draft-ietf-sip-outbound-11 (work in progress),
November 2007.
[RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol", [RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol",
STD 9, RFC 959, October 1985. STD 9, RFC 959, October 1985.
[RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997. Extensions", RFC 2132, March 1997.
[RFC4510] Zeilenga, K., "Lightweight Directory Access Protocol [RFC4510] Zeilenga, K., "Lightweight Directory Access Protocol
(LDAP): Technical Specification Road Map", RFC 4510, (LDAP): Technical Specification Road Map", RFC 4510,
June 2006. June 2006.
skipping to change at page 54, line 7 skipping to change at page 55, line 7
CableLabs CableLabs
858 Coal Creek Circle 858 Coal Creek Circle
Louisville, Co 80027 Louisville, Co 80027
USA USA
Email: sumanth@cablelabs.com Email: sumanth@cablelabs.com
URI: http://www.cablelabs.com/ URI: http://www.cablelabs.com/
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
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