draft-ietf-sipping-config-framework-13.txt   draft-ietf-sipping-config-framework-14.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: April 27, 2008 CableLabs Expires: May 21, 2008 CableLabs
October 25, 2007 November 18, 2007
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-13 draft-ietf-sipping-config-framework-14
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
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The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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This Internet-Draft will expire on April 27, 2008. This Internet-Draft will expire on May 21, 2008.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
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
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3.1. Reference Model . . . . . . . . . . . . . . . . . . . . . 6 3.1. Reference Model . . . . . . . . . . . . . . . . . . . . . 6
3.2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3. Profile Types . . . . . . . . . . . . . . . . . . . . . . 9 3.3. Profile Types . . . . . . . . . . . . . . . . . . . . . . 9
3.4. Profile delivery stages . . . . . . . . . . . . . . . . . 10 3.4. Profile delivery stages . . . . . . . . . . . . . . . . . 10
4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1. Simple Deployment Scenario . . . . . . . . . . . . . . . . 11 4.1. Simple Deployment Scenario . . . . . . . . . . . . . . . . 11
4.2. Devices supporting multiple users from different 4.2. Devices supporting multiple users from different
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 . . . . . . . . . . . . . . . . . . 14 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 . . . . . . . . . . . . . 21 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 . . . . . . . . . . . . . 24 5.2.3. Securing Change Notification . . . . . . . . . . . . . 23
5.3. Additional Considerations . . . . . . . . . . . . . . . . 24 5.3. Additional Considerations . . . . . . . . . . . . . . . . 24
5.3.1. Identities and Credentials . . . . . . . . . . . . . . 24 5.3.1. Identities and Credentials . . . . . . . . . . . . . . 24
5.3.2. Profile Enrollment Request Attempt . . . . . . . . . . 26 5.3.2. Profile Enrollment Request Attempt . . . . . . . . . . 25
5.3.3. Device Types . . . . . . . . . . . . . . . . . . . . . 30 5.3.3. Device Types . . . . . . . . . . . . . . . . . . . . . 29
5.3.4. Profile Data . . . . . . . . . . . . . . . . . . . . . 30 5.3.4. Profile Data . . . . . . . . . . . . . . . . . . . . . 29
5.3.5. Profile Data Frameworks . . . . . . . . . . . . . . . 31 5.3.5. Profile Data Frameworks . . . . . . . . . . . . . . . 30
5.3.6. Additional Profile Types . . . . . . . . . . . . . . . 31 5.3.6. Additional Profile Types . . . . . . . . . . . . . . . 31
5.3.7. Deployment considerations . . . . . . . . . . . . . . 32 5.3.7. Deployment considerations . . . . . . . . . . . . . . 31
5.4. Usage of Outbound . . . . . . . . . . . . . . . . . . . . 32 5.4. Support for NATs . . . . . . . . . . . . . . . . . . . . . 31
6. Event Package Definition . . . . . . . . . . . . . . . . . . . 33 6. Event Package Definition . . . . . . . . . . . . . . . . . . . 32
6.1. Event Package Name . . . . . . . . . . . . . . . . . . . . 33 6.1. Event Package Name . . . . . . . . . . . . . . . . . . . . 32
6.2. Event Package Parameters . . . . . . . . . . . . . . . . . 33 6.2. Event Package Parameters . . . . . . . . . . . . . . . . . 32
6.3. SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . . 36 6.3. SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . . 35
6.4. Subscription Duration . . . . . . . . . . . . . . . . . . 36 6.4. Subscription Duration . . . . . . . . . . . . . . . . . . 35
6.5. NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . 37 6.5. NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . 36
6.6. Notifier Processing of SUBSCRIBE Requests . . . . . . . . 37 6.6. Notifier Processing of SUBSCRIBE Requests . . . . . . . . 36
6.7. Notifier Generation of NOTIFY Requests . . . . . . . . . . 37 6.7. Notifier Generation of NOTIFY Requests . . . . . . . . . . 36
6.8. Subscriber Processing of NOTIFY Requests . . . . . . . . . 38 6.8. Subscriber Processing of NOTIFY Requests . . . . . . . . . 37
6.9. Handling of Forked Requests . . . . . . . . . . . . . . . 38 6.9. Handling of Forked Requests . . . . . . . . . . . . . . . 37
6.10. Rate of Notifications . . . . . . . . . . . . . . . . . . 39 6.10. Rate of Notifications . . . . . . . . . . . . . . . . . . 38
6.11. State Agents . . . . . . . . . . . . . . . . . . . . . . . 39 6.11. State Agents . . . . . . . . . . . . . . . . . . . . . . . 38
7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7.1. Example 1: Device requesting profile . . . . . . . . . . . 39 7.1. Example 1: Device requesting profile . . . . . . . . . . . 38
7.2. Example 2: Device obtaining change notification . . . . . 42 7.2. Example 2: Device obtaining change notification . . . . . 41
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 45
8.1. SIP Event Package . . . . . . . . . . . . . . . . . . . . 46 8.1. SIP Event Package . . . . . . . . . . . . . . . . . . . . 45
8.2. Registry of SIP configuration profile types . . . . . . . 46 8.2. Registry of SIP configuration profile types . . . . . . . 45
9. Security Considerations . . . . . . . . . . . . . . . . . . . 47 9. Security Considerations . . . . . . . . . . . . . . . . . . . 46
9.1. Local-network profile . . . . . . . . . . . . . . . . . . 49 9.1. Local-network profile . . . . . . . . . . . . . . . . . . 47
9.2. Device profile . . . . . . . . . . . . . . . . . . . . . . 50 9.2. Device profile . . . . . . . . . . . . . . . . . . . . . . 48
9.3. User profile . . . . . . . . . . . . . . . . . . . . . . . 51 9.3. User profile . . . . . . . . . . . . . . . . . . . . . . . 50
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 52 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 50
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 53 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 51
11.1. Normative References . . . . . . . . . . . . . . . . . . . 53 11.1. Normative References . . . . . . . . . . . . . . . . . . . 51
11.2. Informative References . . . . . . . . . . . . . . . . . . 54 11.2. Informative References . . . . . . . . . . . . . . . . . . 52
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 54 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 52
Intellectual Property and Copyright Statements . . . . . . . . . . 56 Intellectual Property and Copyright Statements . . . . . . . . . . 54
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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variation in between, one needs to allow for profile delivery via variation in between, one needs to allow for profile delivery via
one, or more, Providers. The framework accomplishes this by one, or more, Providers. The framework accomplishes this by
specifying multiple profile types and a set of profile delivery specifying multiple profile types and a set of profile delivery
stages to obtain them. These are introduced in the sub-sections to stages to obtain them. These are introduced in the sub-sections to
follow. follow.
3.3. Profile Types 3.3. Profile Types
The framework handles the presence of potentially different Providers The framework handles the presence of potentially different Providers
by allowing for multiple profile types. Clients request each profile by allowing for multiple profile types. Clients request each profile
and obtain them from the same, or different, Providers. Additional separately, and obtain them from the same, or different, Providers.
profile types may also be specified. A deployment can also choose to A deployment can also choose to pre-configure the device to request
pre-configure the device to request only a subset of the specified only a subset of the specified profile types. The framework
profile types. The framework specifies three basic profile types, as specifies three basic profile types, as follows:
follows:
Local Network Profile: contains configuration data related to the Local Network Profile: contains configuration data related to the
local network to which a device is directly connected, provided by local network to which a device is directly connected, provided by
the Local Network Provider. the Local Network Provider.
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.
PDSs and devices will implement all the three profile types. Unless Additional profile types may also be specified.
configured otherwise, a device will try to obtain all the three PDSs and devices will implement all the three profile types. A
profile types. A retrieval order is specified by the framework. The device that has not been configured otherwise will try to obtain all
data models associated with each profile type is out of scope for the three profile types, in the order specified by this framework.
this document. Follow-on standardization activities are expected to The device can be configuration with a different behavior via profile
specify such data models. data previously obtained by the device, 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.
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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representative use cases to further illustrate how this Framework can representative use cases to further illustrate how this Framework can
be utilized in SIP deployments. The first use case is simplistic in be utilized in SIP deployments. The first use case is simplistic in
nature, whereas the second is relatively complex. The use cases nature, whereas the second is relatively complex. The use cases
illustrate the effectiveness of the framework in either scenario. illustrate the effectiveness of the framework in either scenario.
For Security Considerations please refer to Section 5 and Section 9. For Security Considerations please refer to Section 5 and Section 9.
4.1. Simple Deployment Scenario 4.1. Simple Deployment Scenario
Description: Consider a deployment scenario (e.g., a small private Description: Consider a deployment scenario (e.g., a small private
enterprise) where a single entity enables the local network, manages enterprise) where a participating device implements this framework
deployed devices and provides SIP services. The devices only attach and is configured, using previously obtained profile data, to request
to the local network, and are pre-configured with a single user. only the device profile. Assume that the device operates in the same
network as the PDS (i.e., there is no NAT) and it obtains its IP
The following assumptions apply: configuration using DHCP. Typical communication between the device
o The device profile data contains all the information necessary and the PDS will traverse one or more SIP proxies, but is not
for the device to participate in the local network and obtain required, and is omitted in this illustration.
services.
o The device is pre-configured to only request the device profile.
o The enrollment notification contains the profile data (profile
content retrieval is not required).
o There are no proxies in the network.
Figure 4 illustrates this use case and highlights the communications Figure 4 illustrates the sequence of events that include device
relevant to the framework specified in this document. startup and a successful profile enrollment for the device profile
that results in device profile data. It then illustrates how a
change in the profile data is delivered via Profile Change
Notification.
+----------------------+ +----------------------+
+--------+ | Local Network, Device| +--------+ | Provider's Network |
| Device | |& SIP Service Provider| | Device | | |
| | | | | | | |
+--------+ | DHCP PDS | +--------+ | DHCP PDS |
+----------------------+ +----------------------+
| | | | | |
(A) |<============== DHCP =============>| | (A) |<============== DHCP =============>| |
| | | |
| | | |
| | | |
(B) |<=========== Profile Enrollment ============>| (B) |<=========== Profile Enrollment ============>|
| | Profile data | | Profile data
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| | | |
| | | |
(B) |<=========== Profile Enrollment ============>| (B) |<=========== Profile Enrollment ============>|
| | Profile data | | Profile data
| | is modified | | is modified
| | | |
(C) |<============ Profile Change ================| (C) |<============ Profile Change ================|
| Notification | | Notification |
| | | |
| | | |
Figure 4: Use Case 1 Figure 4: Use Case 1
The following is an explanation of the interactions in Figure 4. The following is an explanation of the interactions in Figure 4.
(A) Upon initialization, the device obtains IP configuration (A) Upon initialization, the device obtains IP configuration
parameters using DHCP. parameters such as IP address using DHCP.
(B) The device performs Profile Enrollment for the device profile; (B) The device requests profile enrollment for the device profile.
the device profile data is contained in the enrollment Successful enrollment provides it with a notification containing
notification. the device profile data.
(C) Due to a modification of the device profile, a Profile Change (C) Due to a modification of the device profile, a profile change
Notification is sent across to the device, along with the notification is sent across to the device, along with the
modified profile. modified profile.
4.2. Devices supporting multiple users from different Service Providers 4.2. Devices supporting multiple users from different Service Providers
Description: Consider a single device (e.g., Kiosk at an airport) Description: Consider a single device that allows multiple users to
that allows multiple users to obtain services from a list of pre- obtain services from different SIP Service Providers, e.g., a kiosk
configured SIP Service Providers. at an airport.
The following assumptions apply: The following assumptions apply:
o Provider A is the Device and Local Network Provider for the o Provider A is the Device and Local Network Provider for the
device, and the SIP Service Provider for user A; Provider B is device, and the SIP Service Provider for user A; Provider B is
the SIP Service Provider for user B. the SIP Service Provider for user B.
o Profile enrollment always results in content indirection o Profile enrollment always results in content indirection
information requiring profile content retrieval. information requiring profile content retrieval.
o Communication between the device and the PDSs is facilitated by o Communication between the device and the PDSs is facilitated via
SIP proxies. one or more SIP proxies (only one is shown in the illustration).
Figure 4 illustrates the use case and highlights the communications Figure 4 illustrates the use case and highlights the communications
relevant to the framework specified in this document. relevant to the framework specified in this document.
User User User User
A B +----------------------+ +----------------------+ A B +----------------------+ +----------------------+
+--------+ | Provider | | Provider | +--------+ | Provider | | Provider |
| Device | | A | | B | | Device | | A | | B |
| | | | | | | | | | | |
+--------+ | DHCP PROXY PDS | | PROXY PDS | +--------+ | DHCP PROXY PDS | | PROXY PDS |
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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.
The discovery mechanisms for profile enrollment described by the
framework, or the profile data themselves, can result in outbound
proxies that support devices behind NATs, using procedures specified
in [I-D.ietf-sip-outbound].
5. Profile Delivery Framework 5. Profile Delivery Framework
This section specifies the profile delivery framework. It provides This section specifies the profile delivery framework. It provides
the requirements for the three profile delivery stages introduced in the requirements for the three profile delivery stages introduced in
Section 3.4 and presents the associated security requirements. It Section 3.4 and presents the associated security requirements. It
also presents considerations such as back-off and retry mechanisms. also presents considerations such as back-off and retry mechanisms.
5.1. Profile delivery stages 5.1. Profile delivery stages
The three profile delivery stages - enrollment, content retrieval and The three profile delivery stages - enrollment, content retrieval and
change notification - apply to any profile type specified for use change notification - apply separately to each profile type specified
with this framework. The following sub-sections provide the for use with this framework. The following sub-sections provide the
requirements associated with each stage. requirements associated with each stage.
5.1.1. Profile Enrollment 5.1.1. Profile Enrollment
Profile enrollment is the process by means of which a device Profile enrollment is the process by means of which a device
requests, and receives, profile data. Each profile type specified in requests, and receives, profile data. Each profile type specified in
this document requires an independent enrollment request. However, a this document requires an independent enrollment request. However, a
particular PDS can support enrollment for one or more profile types. particular PDS can support enrollment for one or more profile types.
Profile enrollment consists of the following operations, in the Profile enrollment consists of the following operations, in the
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SUBSCRIBE request [RFC3265] for the 'ua-profile' event package, SUBSCRIBE request [RFC3265] for the 'ua-profile' event package,
specified in Section 6. The profile being requested is indicated specified in Section 6. The profile being requested is indicated
using the 'profile-type' parameter. The device MUST transmit the using the 'profile-type' parameter. The device MUST transmit the
SIP SUBSCRIBE message via configured outbound proxies for the SIP SUBSCRIBE message via configured outbound proxies for the
destination domain, or in accordance with RFC 3263 [RFC3263]. destination domain, or in accordance with RFC 3263 [RFC3263].
The device needs certain data to create an enrollment request, The device needs certain data to create an enrollment request,
form a Request URI, and authenticate to the network. This form a Request URI, and authenticate to the network. This
includes the profile provider's domain name, identities and includes the profile provider's domain name, identities and
credentials. Such data can be "configured" during device credentials. Such data can be "configured" during device
manufacturing, by the user, or via profile data retrieval (see manufacturing, by the user, or via profile data enrollment (see
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
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SIP UA instance. Even though every device may get the same (or SIP UA instance. Even though every device may get the same (or
similar) local-network Profile, the uniqueness of the "+sip.instance" similar) local-network Profile, the uniqueness of the "+sip.instance"
parameter provides an important capability. Having unique instance parameter provides an important capability. Having unique instance
ID fields allows the management of the local network to track devices ID fields allows the management of the local network to track devices
present in the network and consequently also manage resources such as present in the network and consequently also manage resources such as
bandwidth allocation. bandwidth allocation.
5.1.4.2. Device Profile Type 5.1.4.2. Device Profile Type
Once associated with a device, the device provider is not expected to Once associated with a device, the device provider is not expected to
change frequently. An exception is a user who changes device change frequently. Thus, the device is allowed to, and SHOULD cache
providers, but retains the device. Thus, the device is allowed to, the Subscription URI for the device profile upon successful
and SHOULD cache the Subscription URI for the device profile upon enrollment. Exceptions include cases where the device identifier has
successful enrollment. Exceptions include cases where the device changed (e.g., new network card), device provider information has
identifier has changed (e.g., new network card), device provider changed (e.g., user initiated change) or the device cannot obtain its
information has changed (e.g., user initiated change) or the device profile using the Subscription URI. Thus, when available, the device
cannot obtain its profile using the Subscription URI. Thus, when MUST use a cached Subscription URI. If no cached URI is available
available, the device MUST use a cached Subscription URI. If no then it needs to create a Subscription URI. To create a Subscription
cached URI is available then it needs to create a Subscription URI. URI, the device needs a device identity and the device provider's
To create a Subscription URI, the device needs a device identity and domain name. Unless already configured, the device needs to discover
the device provider's domain name. Unless already configured, the the necessary information and form the subscription URI. In such
device needs to discover the necessary information and form the cases, the following requirements apply for creating a Subscription
subscription URI. In such cases, the following requirements apply URI for requesting the device profile:
for creating a Subscription URI for requesting the device profile:
o The device MUST use the device identifier and the device o The device MUST populate the user part of the Request URI with the
provider's domain name to form the Request URI. 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 set the "From" field to a value of anonymous@
<device provider's domain>. <device provider's domain>.
o The device MUST include the +sip.instance parameter within the o The device MUST include the +sip.instance parameter within the
'Contact' header, as specified in [I-D.ietf-sip-outbound]. The 'Contact' header, as specified in [I-D.ietf-sip-outbound]. The
device MUST use the same value as the one presented while device MUST use the same value as the one presented while
requesting the local-network profile. requesting the local-network profile.
Note that the discovered AoR for the Request URI can be overridden by Note that the discovered AoR for the Request URI can be overridden by
a special, provisioned, AoR that is unique to the device. In such a special, provisioned, AoR that is unique to the device. In such
cases, the provisioned AoR is used to form the Request URI and to cases, the provisioned AoR is used to form the Request URI and to
populate the From field. populate the From field.
skipping to change at page 20, line 8 skipping to change at page 20, line 15
o The device MUST include the +sip.instance parameter within the o The device MUST include the +sip.instance parameter within the
'Contact' header, as specified in [I-D.ietf-sip-outbound]. The 'Contact' header, as specified in [I-D.ietf-sip-outbound]. The
device MUST use the same value as the one presented while device MUST use the same value as the one presented while
requesting the local-network profile. requesting the local-network profile.
Note that the discovered AoR for the Request URI can be overridden by Note that the discovered AoR for the Request URI can be overridden by
a special, provisioned, AoR that is unique to the device. In such a special, provisioned, AoR that is unique to the device. In such
cases, the provisioned AoR is used to form the Request URI and to cases, the provisioned AoR is used to form the Request URI and to
populate the From field. populate the From field.
If the device is not configured with an AoR, and needs a domain name, If the device is not configured with an AoR, and needs a domain name
it can either use a configured domain name, if available, or discover to populate the Request URI and the From field, it can either use a
it. The options to discover are described below. The device MUST configured domain name, if available, or discover it. The options to
use the results of each successful discovery process for one discover are described below. The device MUST use the results of
enrollment attempt, in the order specified below. each successful discovery process for one enrollment attempt, in the
order specified below.
o Option 1: Devices that support DHCP MUST attempt to obtain the o Option 1: Devices that support DHCP MUST attempt to obtain the
hostname of the outbound proxy during the DHCP process, using the domain name of the outbound proxy during the DHCP process, using
DHCP option for SIP servers defined in [RFC3361] or [RFC3319] (for the DHCP option for SIP servers defined in [RFC3361] or [RFC3319]
IPv4 and IPv6 respectively). (for IPv4 and IPv6 respectively).
o Option 2: Devices that support DHCP MUST attempt to obtain the o Option 2: Devices that support DHCP MUST attempt to obtain the
local IP network domain during the DHCP process (refer to local IP network domain during the DHCP process (refer to
[RFC2132] and [RFC4704] ). [RFC2132] and [RFC4704] ).
o Option 3: Devices MUST use the local network domain name o Option 3: Devices MUST use the local network domain name
(configured or discovered to retrieve the local-network profile), (configured or discovered to retrieve the local-network profile),
prefixing it with the label "_sipuaconfig". 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 device identifier, it MUST use the UUID-based URN representation as
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 MAC Address, it SHOULD o If the device cannot use a non-alterable device identifier, it
use an alternative non-alterable device identifier. For example, SHOULD use an alternative non-alterable device identifier. For
the International Manufacturer's Equipment Identifier (IMEI) for example, the International Manufacturer's Equipment Identifier
mobile devices. (IMEI) for 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 As a note, when the URN is used as the user part of the Request o Note: when the URN is used as the user part of the Request URI, it
URI, it MUST be URL escaped MUST be URL escaped since the colon (":") is not a legal character
The colon (":") is not a legal character in the user part of an in the user part of an addr-spec ([RFC4122]), and must be escaped.
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@
example.com example.com
The ABNF for the UUID representation is provided in [RFC4122] The ABNF for the UUID representation is provided in [RFC4122]
skipping to change at page 21, line 20 skipping to change at page 21, line 25
5.1.4.3. User Profile Type 5.1.4.3. User Profile Type
To create a Subscription URI to request the user profile on behalf of 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 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, statically or dynamically configured on the device (e.g., user input,
or propagated as part of the device profile). Similar to device or propagated as part of the device profile). Similar to device
profiles, the content and propagation of user profiles may differ, profiles, the content and propagation of user profiles may differ,
based on deployment scenarios (i.e., users belonging to the same based on deployment scenarios (i.e., users belonging to the same
domain may - or may not - be provided the same profile). To create a 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 set the Request URI to the user AoR.
o The device MUST populate the "From" field with 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 5.2. Securing Profile Delivery
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. At a minimum, authentication and unwanted elements during transit. For profile data that contains
message integrity are required to ensure that the profile contents sensitive information, authentication and message integrity are
were received by a valid entity, from a valid source, and without any required to ensure that the profile contents were received by a valid
modifications during transit. For profiles that contain sensitive entity, from a valid source, and without any modifications during
data, privacy is required to ensure that the data is not snooped by transit. For profiles that contain sensitive data, privacy is also
unwanted elements. required.
For an overview of potential security threats, refer to Section 9.The For an overview of potential security threats, refer to Section 9.
requirements to address the concerns are required for all stages of For information on how the device can be configured with identities
profile delivery, and are presented in the following subsections. 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 5.2.1. Securing Profile Enrollment
During profile enrollment, the device needs to authenticate two Profile enrollment may result in sensitive profile data. In such
entities. The next-hop entity, i.e., a proxy or a PDS, to which the cases, the PDS MUST authenticate the device, except during the
device transmits the profile enrollment request, and the initial bootstrapping scenario when the device does not have existing
notification from the PDS. On the Provider's side, a PDS that credentials. Additionally, the device MUST authenticate the PDS to
recognizes an identity, such as the user AoR, that will result in ensure that it is obtaining sensitive profile data from a valid PDS,
sensitive (or even non-generic) data included in the initial or except in the bootstrapping scenario.
change notifications, will need to authenticate the device claiming
such identities.
Authentication of the next-hop entity by the device is accomplished
by using the procedures specified in [RFC2818], Section 3.1, over an
establish TLS connection ([RFC4346]). The 'Server Identity' in this
case is always the domain of the next-hop SIP entity. A device
presenting a SIPS URI as a user AoR MUST establish TLS with the next-
hop SIP entity to which it sends the enrollment request. In all
other cases, the device SHOULD still attempt establishment of TLS
with the next-hop SIP entity. An exception is when it is explicitly
configured not to. If it attempts to establish TLS and it fails
because the next-hop SIP entity does not support TLS, the device
SHOULD attempt other resolved next-hop SIP entities prior to
attempting enrollment without TLS. If the device attempts to
establish a TLS session and fails to verify the next-hop entity
(e.g., the domain name could not be verified) the device MUST NOT
continue with the current enrollment request, and must retry with
other resolved next-hop SIP entities. If the device is attempting to
establish TLS, and exhausts the entire list of next-hop entities,
then:
o if the device has a user interface, and unless configured not to,
the device SHOULD prompt the user if it can continue without TLS;
o if the device has no user interface, and unless configured not to,
the device MUST retry enrollment without TLS and without
presenting any configured user AoR (note: this means that user
profiles cannot be retrieved).
In the absence of a Server Identity authenticated TLS session with
the next-hop SIP entity:
o the device MUST NOT respond to any authentication challenges;
o the device MUST ignore any notifications containing sensitive
profile data.
Once enrolled, the device obtains the initial notification. This is To authenticate a device that has been configured with identities and
authenticated using two methods. If this initial notification was credentials as specified in Section 5.3.1 and support profiles
transmitted on the mutually authenticated TLS session established for containing sensitive profile data (refer to Section 5.3.4), devices
enrollment requests, then it is considered authenticated. If not, and PDSs MUST support Digest Authentication as specified in
the device MUST verify the presence of a SIP Identity header from the [RFC3261]. Future enhancements may provide other authentication
PDS and validate that it belongs to the Provider's domain. If the methods such as authentication using X.509 certificates. For the
SIP Identity header is absent or the device cannot validate it, the device to authenticate the PDS, the device MUST mutually authenticate
device MUST reject any sensitive profile data. If the SIP Identity with the PDS during digest authentication (device challenges the
header is present, and the device cannot validate it, then it MUST client that responds with the Authorization header). Transmission of
reject the profile data and retry enrollment. To allow for this sensitive profile data also requires message integrity. This can be
authentication, the PDS SHOULD include the SIP Identity header as provided by configuring the device with a SIPS URI resulting in TLS
specified in [RFC4474]. Exceptions are PDSs that do not serve establishment ([RFC4346]). TLS also prevents offline dictionary
sensitive profiles, or those in deployments where communication with attacks when digest authentication is used. Thus, in the absence of
the PDS in the absence of a mutually authenticated TLS is disallowed. TLS, the device MUST NOT respond to any authentication challenges.
When the SIP Identify header is used, the PDS MUST set the host It is to be noted that the digest credentials used for obtaining
portion of the AoR in the 'From' header to the Provider's domain. profile data via this framework may, or may not, be the same as that
used for SIP registration (see Section 5.3.1).
Note that both Server Identity authentication ([RFC2818]) and SIP When the PDS challenges a profile enrollment request, and it fails,
Identity ([RFC4474] require X.509 certificates. Additionally, the the PDS MAY refuse enrollment or provide profile data without the
use of TLS and mutual authentication also provides message integrity user-specific information (e.g., to bootstrap a device that may have
and privacy between the device and the next-hop entity. When the misplaced credentials). If the device challenges, but fails to
next-hop entity is a proxy, the Provider will need ensure mutual authenticate the PDS, it MUST reject the initial notification and
authentication and integrity between intermediary components such as retry the profile enrollment process. If the device is configured
proxies and PDSs. This is mandatory when a SIPS URI is presented by with a SIPS URI and TLS establishment fails because the next-hop SIP
the device. entity does not support TLS, the device SHOULD attempt other resolved
next-hop SIP entities. When the device establishes TLS with the
next-hop entity, the device MUST use the procedures specified in
[RFC2818], Section 3.1, for authentication, unless it does not have
any configured information to verify the same (e.g., prior to
bootstrapping). The 'Server Identity' in this case is always the
domain of the next-hop SIP entity. If the device attempts
validation, and it fails, it MUST reject the intial notification and
retry profile enrollment. In the absence of TLS and a mechanism for
mutual authentication, the PDS MUST NOT present any sensitive profile
data in the initial notification, except when the device is being
boostrapped. It MAY still use content indirection to transmit
sensitive profile data.
Authentication of the identity requesting the profile is accomplished When a device is being provided with bootstrapping profile data
by the PDS by using the Digest Authentication mechanism, over TLS. containing sensitive information, the PDS SHOULD use the SIP Identity
Thus, devices and PDSs MUST implement Digest Authentication specified header as specified in [RFC4474] within the notification. This helps
in [RFC3261], and TLS as specified in [RFC4346]. If the device with devices that MAY be pre-configured with certificates to validate
presents a user AoR, it should be recognized by the network. If not bootstrapping sources (e.g., list of allowed domain certificates, or
(e.g., discovered or device identities) it may not be known by the a list of root CA certificates using PKI). Further, the profile data
PDS (and hence, may not be associated with credentials). If known by may contain the domain certificate used for creating the SIP Identity
the PDS and the notification will result in data specific to the user header, for devices that are not pre-configured with any information,
AoR, the PDS MUST challenge the request using Digest authentication and can be used to guarantee header and body integrity. It can also
specified in [RFC3261]. If the device successfully responds to the allow the device to present the identity of the PDS to a user for
challenge, it is provided the initial notification, which contains verification (if such an interface exists). When the SIP Identity
the profile data within, or via content indirection. If user header is used, the PDS MUST set the host portion of the AoR in the
authentication fails the PDS MAY refuse enrollment, or provide 'From' header to the Provider's domain (the user portion is a entity-
profile data without the user-specific information. As a note, if specific identifier). If the device is capable of validating the SIP
the PDS attempts authentication in the absence of an authenticated Identity, and it fails, it MUST reject bootstrapping profile data.
TLS session between the device and the next-hop entity, it will be
ignored by the device. A PDS that does not perform authentication
MUST use content indirection to a PCC that supports authentication,
integrity protection and privacy for conveying sensitive 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
sensitive profile data then the PDS MUST use a HTTPS URI for content sensitive profile data then the PDS MUST use a HTTPS URI for content
indirection. PCCs and devices MUST NOT use HTTP for sensitive indirection. PCCs and devices MUST NOT use HTTP for sensitive
profile data. A device MUST authenticate the PCC as specified in 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 [RFC2818], Section 3.1. A device that is being provided with profile
data that contains sensitive data MUST be authenticated using Digest data that contains sensitive data MUST be authenticated using digest
as specified in [RFC2617], with the exception of a device that is authentication as specified in [RFC2617], with the exception of a
being bootstrapped for the first time. The resulting mutually device that is being bootstrapped for the first time via the device
authenticated TLS channel also provides message integrity. profile. The resulting TLS channel also provides message integrity
and privacy.
5.2.3. Securing Change Notification 5.2.3. Securing Change Notification
A successful profile enrollment results in an initial 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 the duration of the subscription. For change notifications
containing sensitive profile data, this framework RECOMMENDS the use
If the device established TLS with the next-hop entity then any such of the SIP Identity header as specified in [RFC4474]. When the SIP
notifications SHOULD be sent over the same TLS session by the PDS. Identity header is used, the PDS MUST set the host portion of the AoR
If the TLS session exists, the device MUST ignore any notifications in the 'From' header to the Provider's domain (the user portion is a
sent outside the TLS session. If no such TLS session exists, the entity-specific identifier). This provides header and body integrity
device MUST NOT accept any sensitive profile data without verifying as well. However, for sensitive profile data that needs privacy and
the presence of, and validating, a SIP Identity header. is not being transmitted over a channel such as TLS, the PDS MUST use
content indirection. Additionally, the PDS MUST also use content
A PDS that does not support TLS MUST use content indirection to a PCC indirection for notifications containing sensitive profile data, when
that supports authentication and integrity protection for conveying the profile enrollment was not authenticated.
sensitive profile data.
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. 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 such as
a user AoR. To do so, the device needs to be configured. This can a user AoR. To do so, the device needs to be configured. This can
be accomplished in one of many ways: 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 USB drives.
End-user interface End-user interface
The end-user may be provided with user AoRs and credentials. The The end-user may be provided with the necessary identities and
end-user can then configure the device (using a user interface), credentials. The end-user can then configure the device (using a
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 three kinds of In such a case the device profile can provide one of the following
information: to bootstap the device:
* Profile data that allows the end-user to communicate with the
device or SIP service provider. The provider can then use any
applicable method (e.g., web portal) to provide the user AoR.
* Profile data that redirects the device to an entity, such as
the PCC, that can provide identity data. 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 the user AoR.
* Profile data containing user identity to be used. This can be
used in cases where the device is initialized for the first
time, or after a factory reset, in the device provider's
network.
If a device presents a user AoR in the enrollment request, the PDS * Profile data that allows the end-user to communicate by non-SIP
can challenge it. To respond to such authentication challenges, the means with the device provider or SIP service provider. The
device needs to have associated credentials. Thus, any of the provider can then use any applicable method (e.g., web portal)
configuration methods indicated above need to provide the user to provide the user AoR.
credentials along with any AoRs. * 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. 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.
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. 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
The configured user AoR and associated credentials can be used in associated with different credentials for digest authentication. In
applicable domains for any of the profile types specified by this such cases, multiple credentials may be configured, and associated
framework. In the absence of the user AoR, the device is not with the realms in which they are to be used. This framework
expected to contain any other credentials. Future enhancements can specifies only digest authentication and the device is not expected
specify additional identities and credentials. to contain any other credentials. Future enhancements can specify
additional identities and credentials such as X.509 certificates.
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 |
+-----+------+ +-----+------+
| |
skipping to change at page 28, line 7 skipping to change at page 27, line 7
,->| Profile +--/Apply Profile-->| Successful | ,->| Profile +--/Apply Profile-->| Successful |
/ | | |(monitoring)|<--. / | | |(monitoring)|<--.
Timeout +--+---------+ +--+----+----+ : Timeout +--+---------+ +--+----+----+ :
/Retry ; ^ | : ; /Retry ; ^ | : ;
`------' | NOTIFY w. Cont.Ind | `-------' `------' | NOTIFY w. Cont.Ind | `-------'
+---/Retrieve Profile-----+ NOTIFY w. Profile +---/Retrieve Profile-----+ NOTIFY w. Profile
/Apply Profile /Apply Profile
Figure 6: Device State Diagram Figure 6: Device State Diagram
As a reminder: As a reminder:
o The timeout for SIP messages is specified by [RFC3261] o The timeout for SIP messages is specified by [RFC3261]. In the
cases where this is not specified such as the timeout to wait for
the initial notification during profile enrollment, it is left to
device implementations or future protocol enhancements.
o The timeout for profile retrieval using content indirection will o The timeout for profile retrieval using content indirection will
be as specified by profile retrieval protocols employed be as specified by profile retrieval protocols employed. If none
exists, it is left to device implementations.
In addition, since profile enrollment is a process unique to this In addition, since profile enrollment is a process unique to this
framework, the device MUST follow the enrollment attempt along with framework, the device MUST follow the enrollment attempt along with
exponential backoff and retry mechanisms as indicated in Figure 7. exponential backoff and retry mechanisms as indicated in Figure 7.
Function for Profile Enrollment () Function for Profile Enrollment ()
Iteration i=0 Init Function: Iteration i=0
Loop: Attempt Loop 1: Attempt
Loop: For each SIP Subscription URI Loop 2: For each SIP Subscription URI
Loop: For each next-hop SIP entity Loop 3: For each next-hop SIP entity
- Prepare & transmit Enrollment Request - Prepare & transmit Enrollment Request
- Await Enrollment Acceptance and initial NOTIFY - Await Enrollment Acceptance and initial NOTIFY
+ If the profile enrollment is successful + If the profile enrollment is successful
= Exit this function() = Exit this function()
+ If profile enrollment fails due to an explicit + If profile enrollment fails due to an explicit
failure or a timeout as specified in RFC3261 failure or a timeout as specified in RFC3261
= Continue with this function() = Continue with the next-hop SIP entity (Loop 3)
End Loop: Next-hop SIP entity contact End Loop: Loop 3
End Loop: SIP Subscription URI formation End Loop: Loop 2
(Note: If you are here, profile enrollment did not succeed) (Note: If you are here, profile enrollment did not succeed)
+ Is any valid cached profile data available? + Is any valid cached profile data available?
= If yes, use it and continue with this function() = If yes, use it and continue with Loop 1
+ If the enrollment request is for a non-mandatory profile + If the enrollment request is for a non-mandatory profile
= then spawn the next profile and continue with this = Start profile enrollment for the next profile,
function() if applicable
- Delay for 2^i*(64*T1); -- this is exponential backoff - Delay for 2^i*(64*T1); -- this is exponential backoff
- increment i; - increment i;
- If i>8, reset i=8; - If i>8, reset i=8;
End loop: Attempt End loop: Loop 1
End Function() End Function()
Figure 7: Profile Enrollment Attempt (pseudo-code) Figure 7: Profile Enrollment Attempt (pseudo-code)
The pseudo-code above (Figure 7) allows for cached profiles to be The pseudo-code above (Figure 7) allows for cached profiles to be
used. However, any cached Local Network profile MUST NOT be used used. However, any cached Local Network profile MUST NOT be used
unless the device can ensure that it is in the same local network unless the device can ensure that it is in the same local network
which provided the cached data. This framework does not provide any which provided the cached data. This framework does not provide any
procedures for local network recognition. Any cached device and user procedures for local network recognition. Any cached device and user
profiles MUST only be used in domains that they are associated with. profiles MUST only be used in domains that they are associated with.
For example, a cached device profile is used only when the associated For example, a cached device profile is used only when the associated
domain matches the current device provider's domain. If a PDS wants domain matches the current device provider's domain. If a PDS wants
to invalidate a profile it may do so by transmitting a NOTIFY with an to invalidate a profile it may do so by transmitting a NOTIFY with an
'empty profile' (not to be confused with an empty NOTIFY). A device 'empty profile', i.e., profile instance without any included data (if
receiving such a NOTIFY MUST discard the applicable profile (i.e., it supported by the profile data model; not to be confused with an empty
cannot even store it in the cache). Additionally, if a factory reset NOTIFY), or via an explicit profile data element that invalidates the
is available and performed on a device, it MUST reset the device to data. A device receiving such a NOTIFY MUST discard the applicable
its initial state prior to any configuration. Specifically, the profile (i.e., it cannot even store it in the cache). Additionally,
device MUST set the device back to the state when it was originally if a factory reset is available and performed on a device, it MUST
distributed. 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 The order of profile enrollment is important. For the profiles
specified in this framework, the device must enroll in the order: specified in this framework, the device must enroll in the following
local-network, device and user. The pseudo-code presented earlier default order: local-network, device and user. The pseudo-code
(Figure 7) differentiates between 'mandatory' and 'non-mandatory' presented earlier (Figure 7) differentiates between 'mandatory' and
profiles. This distinction is left to profile data definitions. '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 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. inform the PDSs of profile retrieval errors such as invalid data.
Follow-on standardization activities are expected to address this Follow-on standardization activities are expected to address this
feature. feature.
5.3.3. Device Types 5.3.3. Device Types
The examples in this framework tend to associate devices with The examples in this framework tend to associate devices with
entities that are accessible to end-users. However, this is not entities that are accessible to end-users. However, this is not
skipping to change at page 32, line 39 skipping to change at page 31, line 46
o The relationship between devices and users can be many-to-many o The relationship between devices and users can be many-to-many
(e.g., a particular device may allow for many users to obtain (e.g., a particular device may allow for many users to obtain
subscription services through it, and individual users may have subscription services through it, and individual users may have
access to multiple devices). access to multiple devices).
o Each user may have different preferences for use of services, and o Each user may have different preferences for use of services, and
presentation of those services in the device user interface. presentation of those services in the device user interface.
o Each user may have different personal information applicable to o Each user may have different personal information applicable to
use of the device, either as related to particular services, or use of the device, either as related to particular services, or
independent of them. independent of them.
5.4. Usage of Outbound 5.4. Support for NATs
PDSs that support devices behind NATs, and devices that can be behind PDSs that support devices behind NATs, and devices that can be behind
NATs can use procedures specified in [I-D.ietf-sip-outbound]. The NATs can use procedures specified in [I-D.ietf-sip-outbound]. The
Outbound proxies can be configured or discovered. Clients that Outbound proxies can be configured or discovered. Clients that
support such behavior MUST include the 'outbound' option-tag in a support such behavior MUST include the 'outbound' option-tag in a
Supported header field value, and add the "ob" parameter as specified Supported header field value, and add the "ob" parameter as specified
in [I-D.ietf-sip-outbound] within the SIP SUBSCRIBE for profile in [I-D.ietf-sip-outbound] within the SIP SUBSCRIBE for profile
enrollment. enrollment.
6. Event Package Definition 6. Event Package Definition
skipping to change at page 34, line 6 skipping to change at page 33, line 6
sub-sections. sub-sections.
6.2.1. profile-type 6.2.1. profile-type
The "profile-type" parameter is used to indicate the token name of The "profile-type" parameter is used to indicate the token name of
the profile type the user agent wishes to obtain and to be notified the profile type the user agent wishes to obtain and to be notified
of subsequent changes. This document defines three logical types of of subsequent changes. This document defines three logical types of
profiles and their token names. They are as follows: profiles and their token names. They are as follows:
local-network: specifying the "local-network" type profile indicates local-network: specifying the "local-network" type profile indicates
the desire for profile data specific to the local network. the desire for profile data, and potentially, profile change
notifications specific to the local network.
device: specifying the "device" type profile(s) indicates the desire device: specifying the "device" type profile(s) indicates the desire
for the profile data and profile change notification that is for the profile data, and potentially, profile change notification
specific to the device or user agent. that is specific to the device or user agent.
user: Specifying "user" type profile indicates the desire for the user: Specifying "user" type profile indicates the desire for the
profile data and profile change notification specific to the user. profile data, and potentially, profile change notification
specific to the user.
The profile type is identified in the Event header parameter: The profile type is identified in the Event header parameter:
"profile-type". A separate SUBSCRIBE dialog is used for each profile "profile-type". A separate SUBSCRIBE dialog is used for each profile
type. Thus, the subscription dialog on which a NOTIFY arrives type. Thus, the subscription dialog on which a NOTIFY arrives
implies which profile's data is contained in, or referred to, by the implies which profile's data is contained in, or referred to, by the
NOTIFY message body. The Accept header of the SUBSCRIBE request MUST NOTIFY message body. The Accept header of the SUBSCRIBE request MUST
include the MIME types for all profile content types for which the include the MIME types for all profile content types for which the
subscribing user agent wishes to retrieve profiles, or receive change subscribing user agent wishes to retrieve profiles, or receive change
notifications. notifications.
skipping to change at page 35, line 24 skipping to change at page 34, line 26
The "effective-by" parameter in the Event header of the NOTIFY The "effective-by" parameter in the Event header of the NOTIFY
request specifies the maximum number of seconds before the user agent 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 parameter MAY be provided in the NOTIFY request for any of the
profile types. A value of 0 (zero) indicates that the subscribing 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 (despite possible service interruptions). This gives the PDS the
power to control when the profile is effective. This may be power to control when the profile is effective. This may be
important to resolve an emergency problem or disable a user agent important to resolve an emergency problem or disable a user agent
immediately. The "effective-by" parameter is ignored in all messages immediately. If it is absent, the device SHOULD attempt to make the
other than the NOTIFY request. In the following ABNF, EQUAL and profile data effective at the earliest possible opportunity that does
DIGIT are defined in [RFC3261]. 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 Effective-By = "effective-by" EQUAL 1*DIGIT
6.2.4. Summary of event parameters 6.2.4. Summary of event parameters
The following are example Event headers which may occur in SUBSCRIBE The following are example Event headers which may occur in SUBSCRIBE
requests. These examples are not intended to be complete SUBSCRIBE requests. These examples are not intended to be complete SUBSCRIBE
requests. requests.
Event: ua-profile;profile-type=device; Event: ua-profile;profile-type=device;
skipping to change at page 36, line 34 skipping to change at page 35, line 39
profile-type || device | user | local-network profile-type || device | user | local-network
============================================= =============================================
vendor || | | vendor || | |
model || | | model || | |
version || | | version || | |
effective-by || o | o | o effective-by || o | o | o
6.3. SUBSCRIBE Bodies 6.3. SUBSCRIBE Bodies
This package defines no use of the SUBSCRIBE request body. If This package defines no use of the SUBSCRIBE request body. If
present, it SHOULD be ignored. The exception being future present, it SHOULD be ignored. Exceptions include future
enhancements to the framework which may specify a use for the enhancements to the framework which may specify a use for the
SUBSCRIBE request body. SUBSCRIBE request body.
6.4. Subscription Duration 6.4. Subscription Duration
The duration of a subscription is specific to SIP deployments and no The duration of a subscription is specific to SIP deployments and no
specific recommendation is made by this Event Package. If absent, a specific recommendation is made by this Event Package. If absent, a
value of 86400 seconds (24 hours; 1 day) is RECOMMENDED since the value of 86400 seconds (24 hours; 1 day) is RECOMMENDED since the
presence (or absence) of a device subscription is not time critical presence (or absence) of a device subscription is not time critical
to the regular functioning of the PDS. to the regular functioning of the PDS.
skipping to change at page 37, line 12 skipping to change at page 36, line 13
subscription, can be accomplished by setting the 'Expires' parameter subscription, can be accomplished by setting the 'Expires' parameter
to a value of Zero, as specified in [RFC3265]. to a value of Zero, as specified in [RFC3265].
6.5. NOTIFY Bodies 6.5. NOTIFY Bodies
The framework specifying the Event Package allows for the NOTIFY body The framework specifying the Event Package allows for the NOTIFY body
to contain the profile data, or a pointer to the profile data using to contain the profile data, or a pointer to the profile data using
content indirection. For profile data delivered via content content indirection. For profile data delivered via content
indirection, i.e., a pointer to a PCC, then the Content-ID MIME indirection, i.e., a pointer to a PCC, then the Content-ID MIME
header, as described in [RFC4483] MUST be used for each Profile header, as described in [RFC4483] MUST be used for each Profile
document URI. At a minimum, the "http:" and "https:" URI schemes document URI. At a minimum, the "http:" [RFC2616] and "https:"
MUST be supported; other URI schemes MAY be supported based on the [RFC2818] URI schemes MUST be supported; other URI schemes MAY be
Profile Data Frameworks (examples include FTP [RFC0959], HTTP supported based on the Profile Data Frameworks (examples include FTP
[RFC2616], HTTPS [RFC2818], LDAP [RFC4510] and XCAP [RFC4825] ). [RFC0959], LDAP [RFC4510] and XCAP [RFC4825] ).
A non-empty NOTIFY body MUST include a MIME type specified in the A non-empty NOTIFY body MUST include a MIME type specified in the
'Accept' header of the SUBSCRIBE. Further, if the Accept header of 'Accept' header of the SUBSCRIBE. Further, if the Accept header of
the SUBSCRIBE included the MIME type message/external-body the SUBSCRIBE included the MIME type message/external-body
(indicating support for content indirection) then the PDS MAY use (indicating support for content indirection) then the PDS MAY use
content indirection in the NOTIFY body for providing the profiles. content indirection in the NOTIFY body for providing the profiles.
6.6. Notifier Processing of SUBSCRIBE Requests 6.6. Notifier Processing of SUBSCRIBE Requests
A successful SUBSCRIBE request results in a NOTIFY with either A successful SUBSCRIBE request results in a NOTIFY with either
skipping to change at page 37, line 40 skipping to change at page 36, line 41
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. either accept or 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. no body or content data) or provide no profile information (i.e., empty NOTIFY).
indirection).
If the URI in the SUBSCRIBE request is a known identity and the If the identity indicated in the SUBSCRIBE request (From header) is a
requested profile information is available (i.e. as specified in the known identity and the requested profile information is available
profile-type parameter of the Event header), the Notifier SHOULD send (i.e. as specified in the profile-type parameter of the Event
a NOTIFY with profile data. Profile data MAY be sent as profile header), the Notifier SHOULD send a NOTIFY with profile data.
contents or via Content Indirection (if the content indirection MIME Profile data MAY be sent as profile contents or via Content
type was included in the Accept header). The Notifier MUST NOT use Indirection (if the content indirection MIME type was included in the
any scheme that was not indicated in the "schemes" Contact header Accept header). The Notifier MUST NOT use any scheme that was not
field. indicated in the "schemes" Contact header field.
The Notifier MAY specify when the new profiles must be made effective The Notifier MAY specify when the new profiles must be made effective
by the Subscriber by specifying a maximum time in seconds (zero or by the Subscriber by specifying a maximum time in seconds (zero or
more) in the "effective-by" event header parameter. more) in the "effective-by" event header parameter.
If the SUBSCRIBE was received over an integrity protected SIP If the SUBSCRIBE was received over an integrity protected SIP
communications channel, the Notifier SHOULD send the NOTIFY over the communications channel, the Notifier SHOULD send the NOTIFY over the
same channel. same channel.
6.8. Subscriber Processing of NOTIFY Requests 6.8. Subscriber Processing of NOTIFY Requests
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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 timeframe 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. The Subscriber wishes to support alternative with those URI schemes. If the Subscriber wishes to support
URI schemes it MUST be indicated in the "schemes" Contact header alternative URI schemes they MUST each be indicated in the "schemes"
field parameter as defined in [RFC4483]. The Subscriber MUST also be Contact header field parameter as defined in [RFC4483]. The
prepared to receive a NOTIFY request with no body. The subscriber Subscriber MUST also be prepared to receive a NOTIFY request with no
MUST NOT reject the NOTIFY request with no body. The subscription body. The subscriber MUST NOT reject the NOTIFY request with no
dialog MUST NOT be terminated by a NOTIFY with no body. body. The subscription dialog MUST NOT be terminated by a empty
NOTIFY, i.e., with no body.
6.9. Handling of Forked Requests 6.9. Handling of Forked Requests
This Event package allows the creation of only one dialog as a result 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 of an initial SUBSCRIBE request as described in section 4.4.9 of
[RFC3265]. It does not support the creation of multiple [RFC3265]. It does not support the creation of multiple
subscriptions using forked SUBSCRIBE requests. subscriptions using forked SUBSCRIBE requests.
6.10. Rate of Notifications 6.10. Rate of Notifications
skipping to change at page 39, line 19 skipping to change at page 38, line 19
Package specification does not specify a throttling or minimum period Package specification does not specify a throttling or minimum period
between NOTIFY requests between NOTIFY requests
6.11. State Agents 6.11. State Agents
State agents are not applicable to this Event Package. State agents are not applicable to this Event Package.
7. Examples 7. Examples
This section provides examples along with sample SIP message bodies This section provides examples along with sample SIP message bodies
relevant to this framework. Both the examples are derived from a relevant to this framework. Both the examples are derived from the
snapshot of Section 4.1, specifically the request for the device use case illustrated in Section 4.1, specifically the request for the
profile. The examples are purely informative and in case of device profile. The examples are informative only.
conflicts with the framework or protocols used for illustration, the
latter should be deemed normative.
7.1. Example 1: Device requesting profile 7.1. Example 1: Device requesting profile
This example illustrates the detailed message flows between the This example illustrates the detailed message flows between the
device and the SIP Service Provider's network for requesting and device and the SIP Service Provider's network for requesting and
retrieving the profile (the flow uses the device profile as an retrieving the profile (the flow uses the device profile as an
example). example).
The following are assumed for this example: The following are assumed for this example:
skipping to change at page 41, line 9 skipping to change at page 40, line 9
framework. framework.
* Note: Some of the header fields (e.g., SUBSCRIBE, Event, via) * Note: Some of the header fields (e.g., SUBSCRIBE, Event, via)
are continued on a separate line due to format constraints of are continued on a separate line due to format constraints of
this document. this document.
SUBSCRIBE sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB SUBSCRIBE sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB
@example.com SIP/2.0 @example.com SIP/2.0
Event: ua-profile;profile-type=device;vendor="vendor.example.net"; Event: ua-profile;profile-type=device;vendor="vendor.example.net";
model="Z100";version="1.2.3"; model="Z100";version="1.2.3";
From: sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB From: anonymous@example.com;tag=1234
@example.com;tag=1234
To: sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB@example.com To: sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB@example.com
Call-ID: 3573853342923422@192.0.2.44 Call-ID: 3573853342923422@192.0.2.44
CSeq: 2131 SUBSCRIBE CSeq: 2131 SUBSCRIBE
Contact: sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB Contact: sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB
@example.com @192.168.1.44
;+sip.instance="<urn:uuid:00000000-0000-0000-0000-123456789AB0>" ;+sip.instance="<urn:uuid:00000000-0000-0000-0000-123456789AB0>"
;schemes="http,https" ;schemes="http,https"
Via: SIP/2.0/TCP 192.0.2.41; Via: SIP/2.0/TCP 192.0.2.41;
branch=z9hG4bK6d6d35b6e2a203104d97211a3d18f57a branch=z9hG4bK6d6d35b6e2a203104d97211a3d18f57a
Accept: message/external-body, application/x-z100-device-profile Accept: message/external-body, application/x-z100-device-profile
Content-Length: 0 Content-Length: 0
(SRes) (SRes)
the SUBSCRIBE request is received by a SIP Proxy in the Service the SUBSCRIBE request is received by a SIP Proxy in the Service
skipping to change at page 42, line 6 skipping to change at page 41, line 6
secure communications channel (e.g., TLS). secure communications channel (e.g., TLS).
(NTFY) (NTFY)
subsequently, the PDS transmits a SIP NOTIFY message indicating subsequently, the PDS transmits a SIP NOTIFY message indicating
the profile location the profile location
* Note: Some of the fields (e.g., content-type) are continued on * Note: Some of the fields (e.g., content-type) are continued on
a separate line due to format constraints of this document. a separate line due to format constraints of this document.
NOTIFY sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB NOTIFY sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB
@192.0.2.44 SIP/2.0 @192.168.1.44 SIP/2.0
Event: ua-profile;effective-by=3600 Event: ua-profile;effective-by=3600
From: sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB@example.com From: sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB@example.com
;tag=abca ;tag=abca
To: sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB@example.com To: sip:urn%3auuid%3a00000000-0000-1000-0000-00FF8D82EDCB@example.com
;tag=1231 ;tag=1234
Call-ID: 3573853342923422@192.0.2.44 Call-ID: 3573853342923422@192.0.2.44
CSeq: 322 NOTIFY CSeq: 322 NOTIFY
Via: SIP/2.0/UDP 192.0.2.3; Via: SIP/2.0/UDP 192.0.2.3;
branch=z9hG4bK1e3effada91dc37fd5a0c95cbf6767d0 branch=z9hG4bK1e3effada91dc37fd5a0c95cbf6767d0
MIME-Version: 1.0 MIME-Version: 1.0
Content-Type: message/external-body; access-type="URL"; Content-Type: message/external-body; access-type="URL";
expiration="Mon, 01 Jan 2010 09:00:00 UTC"; expiration="Mon, 01 Jan 2010 09:00:00 UTC";
URL="http://example.com/z100-000000000000.html"; URL="http://example.com/z100-000000000000.html";
size=9999; size=9999;
hash=10AB568E91245681AC1B hash=10AB568E91245681AC1B
skipping to change at page 45, line 32 skipping to change at page 44, line 32
(A-RS) Device A accepts the NOTIFY and sends a 200 OK (A-RS) Device A accepts the NOTIFY and sends a 200 OK
(B-NT) PDS transmits a NOTIFY message to device B indicating the (B-NT) PDS transmits a NOTIFY message to device B 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@192.0.2.43 SIP/2.0 NOTIFY sip:userX@192.0.2.43 SIP/2.0
Event: ua-profile;effective-by=3600 Event: ua-profile;effective-by=3600
From: sip:userX@sip.example.net;tag=abce From: sip:userX@sip.example.net;tag=abce
To: sip:userX@sip.example.net.net;tag=1235 To: sip:userX@sip.example.net.net;tag=1234
Call-ID: 3573853342923422@192.0.2.43 Call-ID: 3573853342923422@192.0.2.43
CSeq: 322 NOTIFY CSeq: 322 NOTIFY
Via: SIP/2.0/UDP 192.0.2.3; Via: SIP/2.0/UDP 192.0.2.3;
branch=z9hG4bK1e3effada91dc37fd5a0c95cbf6767d2 branch=z9hG4bK1e3effada91dc37fd5a0c95cbf6767d2
MIME-Version: 1.0 MIME-Version: 1.0
Content-Type: message/external-body; access-type="URL"; Content-Type: message/external-body; access-type="URL";
expiration="Mon, 01 Jan 2010 09:00:00 UTC"; expiration="Mon, 01 Jan 2010 09:00:00 UTC";
URL="http://www.example.com/user-x-profile.html"; URL="http://www.example.com/user-x-profile.html";
size=9999; size=9999;
hash=123456789AAABBBCCCDD hash=123456789AAABBBCCCDD
skipping to change at page 47, line 29 skipping to change at page 46, line 29
CONTACT: CONTACT:
------- -------
sumanth@cablelabs.com sumanth@cablelabs.com
Daniel Petrie dan.ietf AT SIPez DOT com Daniel Petrie dan.ietf AT SIPez DOT com
Note to RFC editor: Please replace RFCXXXX with the RFC number Note to RFC editor: Please replace RFCXXXX with the RFC number
assigned to this document. assigned to this document.
9. Security Considerations 9. Security Considerations
The framework specified in this document enables profile data The framework specified in this documents specifies profile delivery
delivery to devices. It specifies profile delivery stages, an event stages, an event package and three profile types to enable profile
package and several profile types. delivery. The profile delivery stages are: enrollment, content
retrieval, and change notification. The event package helps with
There are three stages: Enrollment, Content Retrieval, and Change enrollment and change notifications. Each profile type allows for
Notification. profile retrieval from a PDS belonging to a specific provider.
+------+ +-----+
| | | |
|Device| | PNC |
| | | |
+------+ +-----+
| |
| Profile Enrollment |
|---------------------->|
| |
| Initial Notification |
|<----------------------|
| |
+------+ +-----+
| | | |
|Device| | PNC |
| | | |
+------+ +-----+
| |
| Profile Enrollment |
|---------------------->|
| |
| Change Notification |
|<----------------------|
| |
+------+ +-----+
| | | |
|Device| | PCC |
| | | |
+------+ +-----+
| |
| Profile Request | (When content
|---------------------->| indirection
| | is used)
| Profile Response |
|<----------------------|
| |
PNC = Profile Notification Component
PCC = Profile Content Component
Figure 23: Profile Delivery Stages
Enrollment allows a device to request a profile. To transmit the Enrollment allows a device to request, and if successful, enroll with
request the device relies on configured, cached or discovered data. a PDS to obtain profile data. To transmit the request the device
Such data includes provider domain names, identities, and relies on configured, cached or discovered data. Such data includes
credentials. The device either uses configured Outbound proxies or provider domain names, identities, and credentials. The device
discoveries the next-hop entity using [RFC3263] that can result in a either uses configured outbound proxies or discovers the next-hop
SIP proxy or the PDS. It then transmits the request, after entity using [RFC3263] that can result in a SIP proxy or the PDS. It
establishing a TLS session if required. If obtained via a SIP proxy, then transmits the request. A SIP Proxy receving the request uses
the Request-URI is used to route it to a PDS (via an authoritative the Request-URI and event header contents to route it to a PDS (via
SIP proxy, 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
the presented identity (if any) or admit the enrollment. any contained identity or admit the enrollment. Authorization rules
Authorization then decides if the enrollment is accepted. If then decide if the enrollment gets accepted. If accepted, the PDS
accepted, the PDS sends an initial notification that contains either sends an initial notification that contains either the profile data,
the profile data, or content indirection information. The profile or content indirection information. The profile data can contain
data can contain information specific to an entity (such as the generic profile data (common across multiple devices) or information
device or a user) and may contain sensitive information (such as specific to an entity (such as the device or a user). If specific to
credentials). Compromise of such data can lead to threats such as an entity, it and may contain sensitive information such as
impersonation attacks (establishing rogue sessions), theft of service credentials. Compromise of sensitive data can lead to threats such
(if services are obtainable), and zombie attacks. Even if the as impersonation attacks (establishing rogue sessions), theft of
profile data is provided using content indirection, PCC information service (if services are obtainable), and zombie attacks. Even if
within the notification can lead to threats such as denial of service the profile data is provided using content indirection, PCC
attacks (rogue devices bombard the PCC with requests for a specific information within the notification can lead to threats such as
profile) and attempts to modify erroneous data onto the PCC (since denial of service attacks (rogue devices bombard the PCC with
the location and format may be known). It is also important for the requests for a specific profile) and attempts to modify erroneous
device to ensure the authenticity of the PNC since impersonation of data onto the PCC (since the location and format may be known). It
the SIP service provider can lead to Denial of Service, Man-in-the- is also important for the device to ensure the authenticity of the
Middle attacks, etc. 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
from a PCC. This communication is accomplished using one of many via content indirection from a PCC. This communication is
profile delivery protocols or frameworks, such as HTTP or HTTPS as accomplished using one of many profile delivery protocols or
specified in this document. However, since the profile data returned frameworks, such as HTTP or HTTPS as specified in this document.
is subject to the same considerations as that sent via profile However, since the profile data returned is subject to the same
notification, the same threats exist. considerations as that sent via profile notification, similar threats
exist. 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 PDS
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-specific considerations follow. The following sub-sections highlight the security considerations that
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 capable of accessing the network. that is provided to every device that requests the local-network
Such a PDS may not implement any authentication requirements or TLS. profile. Such a PDS may not implement any authentication
requirements or TLS.
Alternatively, certain deployments may require the entities - device Alternatively, certain deployments may require the entities - device
and the PDS - to mutually authenticate prior to profile enrollment. and the PDS - to authenticate each other prior to succesful profile
Such networks may pre-configure user identities to the devices and enrollment. Such networks may pre-configure user identities to the
allow user-specific local-network profiles. In such networks the PDS devices and allow user-specific local-network profiles. In such
will contain X.509 certificates and support TLS, and the devices are networks the PDS will support digest, and the devices are configured
pre-configured with user identities, credentials and implement TLS. 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 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 MiM or PDS
impersonation attacks. This framework requires that a device reject impersonation attacks. This framework requires that a device reject
sensitive data, such as credentials, from unauthenticated local- sensitive data, such as credentials, from unauthenticated local-
network sources (exceptions are noted). It also prohibits devices network sources. It also prohibits devices from responding to
from responding to authentication challenges from unauthenticated authentication challenges in the absence of TLS. Responding to
PDSs. Responding to unauthenticated challenges allows for dictionary unauthenticated challenges allows for dictionary attacks that can
attacks that can reveal weak passwords. reveal weak passwords.
If deployments prefer devices to obtain profiles only from pre-
configured domains (e.g., partner networks), they MAY require such
devices to establish TLS prior to obtaining the local-network
profile.
The use of SIP Identity is useful in cases when TLS is not used but The use of SIP Identity is useful for the device to validate
the device still obtains a profile (e.g., the local-network profile). notifications in the absence of a secure channel such as TLS. In
In such cases the device provider, or the user, can use the SIP such cases the device can validate the SIP Identity header to verify
Identity header to verify the source of the local-network profile. the source of the local-network profile. However, the presence of
However, the presence of the header does not guarantee the validity the header does not guarantee the validity of the data. It verifies
of the data. It verifies the source and confirms data integrity, but the source and confirms data integrity, but the data obtained from an
the data obtained from an undesired source may still be invalid undesired source may still be invalid, e.g., invalid outbound proxy
(e.g., it can be invalid or contain malicious content). information, resulting in Denial of Service. Thus, devices
requesting the local-network profile from 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 of trials and self-subscription to SIP services (not to for purposes such as trials, self-subscription (not to be confused
be confused with [RFC3265]), emergency services with [RFC3265]) and emergency services ([I-D.ietf-ecrit-phonebcp]).
([I-D.ietf-ecrit-phonebcp]), or to devices that are known by the PDS.
Devices that are not aware of any device providers (i.e., no cached
or configured information) will have to discover a PDS in the network
they connect to. In such a case the discovered information may lead
them to a PDS that provides enough profile data to enable device
operation. This configuration can also provide a user AoR that can
be used in the local-network and credentials (temporary or long-term)
that will be used for future communication with the network. This
may enable the device to communicate with a device provider who
allows for self-subscription (e.g., web interface, interactive voice
response or customer service representative). It may also allow the
device a choice of device providers and allow the end-user to choose
one. It is to be noted that such devices are at the mercy of the
network they connect to initially. 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 (PINs 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 the large-entropy credentials
MUST be used, or quickly replaced with such, to minimize the impact
of dictionary attacks. Future enhancements to this framework may
specify device capabilities that allow for mutual authentication
without pre-configuration (e.g., X.509 certificates using PKI).
Once a device is associated with a device provider (either This framework allows for the device profile to be used for
dynamically or via pre-configuration using a user interface or prior bootstrapping a device. Such boostrapping profile data may contain
to distribution), the device profile is vital to device operation. enough information to connect to a Provider. For example, it may
This is because the device profile can contain important operational enable the device to communicate with a device provider, allowing for
information such as users that are to be allowed access (white-list trial or self-subscription services via visual or audio interfaces
or black-list), user credentials (if required) and other sensitive (e.g., interactive voice response), or customer service
information. Thus, it is also necessary to ensure that the device representatives. The profile data may also allow the device a choice
profile is not obtained via an unauthenticated source or tampered of device providers and allow the end-user to choose one. The
during transit. Thus the framework requires that devices supporting profile data may also contain identities and credentials (temporary
any sensitive device profiles establish next-hop authenticated TLS or long-term) that can be used to obtain further profile data from
connections prior to device enrollment. However, given the the network. If it contains such sensitive data, the framework
importance of the device profile it also allows for profile requests recommends the use of the SIP Identity header by the PDS. However,
in cases where the PDS does not implement TLS. It also allows the to be able to validate the header, the device needs to be pre-
PDSs to perform authentication without requiring TLS. However, this configured with the knowledge of allowable domains or certificates
leaves the communication open to MiM attacks and SHOULD be avoided. for validation (e.g., using PKI). If not, the device can still
Additionally any credential used SHOULD be of sufficiently large- guarantee header and body integrity if the profile data contains the
entropy to prevent dictionary attacks. Devices SHOULD use the domain certificate (but the data can still be invalid or malicious).
'cnonce' parameter ([RFC2617]) to thwart "offline" dictionary In such cases, devices supporting user interfaces may obtain
attacks. confirmation from the user trying to boostrap 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
(PINs 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 then large-entropy credentials MUST be used, or
quickly replaced with such, to minimize the impact of dictionary
attacks. Future enhancements to this framework may specify device
capabilities that allow for authentication without any pre-
configuration (e.g., X.509 certificates using PKI). Alternatively, a
PDS can use secure content indirection mechanisms 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 that 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.
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. Thus, PDSs are prohibited from accepting user SIP service provider. PDSs are required to reject user profile
profile enrollment requests for users that are unknown in the enrollment requests for any users that are unknown in the network.
network. If the user AoR is a SIPS URI then the device is required For known user AoRs that are allowed to retrieve profiles, the
to establish a next-hop authenticated TLS session. This framework security considerations are similar to that of the device profile
requires this for profiles with sensitive data. If it is a SIP URI, (except for bootstrapping).
then the device is still recommended to attempt TLS establishment to
ensure protection against rogue PDSs. Further, the PDS will
authenticate requests prior to accepting profile enrollment requests
that can result in sensitive data. A mutually authenticated TLS
channel provides message integrity and privacy.
10. Acknowledgements 10. Acknowledgements
The author appreciates all those who contributed and commented on the The author appreciates all those who contributed and commented on the
many iterations of this document. Detailed comments were provided by many iterations of this document. Detailed comments were provided by
the following individuals: Jonathan Rosenberg from Cisco, Henning the following individuals: Jonathan Rosenberg from Cisco, Henning
Schulzrinne from Columbia University, Cullen Jennings from Cisco, Schulzrinne from Columbia University, Cullen Jennings from Cisco,
Rohan Mahy from Plantronics, Rich Schaaf from Pingtel, Volker Hilt Rohan Mahy from Plantronics, Rich Schaaf from Pingtel, Volker Hilt
from Bell Labs, Adam Roach of Estacado Systems, Hisham Khartabil from from Bell Labs, Adam Roach of Estacado Systems, Hisham Khartabil from
Telio, Henry Sinnreich from MCI, Martin Dolly from AT&T Labs, John Telio, Henry Sinnreich from MCI, Martin Dolly from AT&T Labs, John
skipping to change at page 52, line 40 skipping to change at page 50, line 48
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). proposal) and John Elwell from Siemens.
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
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