Internet DRAFT - draft-li-scim-user-scenarios
draft-li-scim-user-scenarios
SCIM WG K. Li
Internet-Draft Huawei Technologies
Intended status: Informational Jan 2013
Expires: July 5, 2013
SCIM User Scenarios
draft-li-scim-user-scenarios-00
Abstract
This document lists the user scenarios of System for Cross-domain
Identity Management (SCIM).
Status of this Memo
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This Internet-Draft will expire on July 5, 2013.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. SCIM User Scenarios . . . . . . . . . . . . . . . . . . . . . 3
2.1. Background & Context . . . . . . . . . . . . . . . . . . . 3
2.2. Model Concepts . . . . . . . . . . . . . . . . . . . . . . 3
2.2.1. Triggers . . . . . . . . . . . . . . . . . . . . . . . 3
2.2.2. Actors . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.3. Modes & Flows . . . . . . . . . . . . . . . . . . . . 5
2.2.4. Bulk & Batch Operational Semantics . . . . . . . . . . 6
2.3. Cloud Service Provider to Cloud Service Provider Flows
(CSP->CSP) . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3.1. CSP->CSP - Create Identity (Push) . . . . . . . . . . 6
2.3.2. CSP->CSP - Update Identity (Push) . . . . . . . . . . 7
2.3.3. CSP->CSP - Delete Identity (Push) . . . . . . . . . . 7
2.3.4. CSP->CSP - SSO Trigger (Push) . . . . . . . . . . . . 7
2.3.5. CSP->CSP - SSO Trigger (Pull) . . . . . . . . . . . . 8
2.3.6. CSP->CSP - Password Reset (Push) . . . . . . . . . . . 8
2.4. Enterprise Cloud Subscriber to Cloud Service Provider
Flows(ECS->CSP) . . . . . . . . . . . . . . . . . . . . . 8
2.4.1. ECS->CSP - Create Identity (Push) . . . . . . . . . . 8
2.4.2. ECS ->CSP - Update Identity (Push) . . . . . . . . . . 9
2.4.3. ECS ->CSP - Delete Identity (Push) . . . . . . . . . . 9
2.4.4. ECS ->CSP - SSO Pull . . . . . . . . . . . . . . . . . 9
3. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 9
4. Security considerations . . . . . . . . . . . . . . . . . . . 9
5. IANA considerations . . . . . . . . . . . . . . . . . . . . . 9
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
7. Informative References . . . . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
This document describes the SCIM user scenarios. The document's
objective is to help with understanding of the design and
applicability of SCIM schema [I-D.ietf-scim-core-schema] and SCIM
protocol [I-D.ietf-scim-api].
The following section provides the abbreviated descriptions of the
user scenarios.
2. SCIM User Scenarios
2.1. Background & Context
The Simple Cloud Identity Management (SCIM) specification is designed
to make managing user identity in cloud based applications and
services easier. The specification suite seeks to build upon
experience with existing schemas and deployments, placing specific
emphasis on simplicity of development and integration, while applying
existing authentication, authorization, and privacy models. It's
intent is to reduce the cost and complexity of user management
operations by providing a common user schema and extension model, as
well as binding documents to provide patterns for exchanging this
schema using standard protocols. In essence, make it fast, cheap,
and easy to move users in to, out of, and around the cloud.
The SCIM user scenarios are overview user stories designed to help
clarify the intended scope of the SCIM effort.
2.2. Model Concepts
2.2.1. Triggers
Quite simply, triggers are actions or activities that start SCIM
flows. Triggers may not be relevant at the protocol or the schema,
they really serve to help identity the type or activity that resulted
in a SCIM protocol exchange. Triggers make use of the traditional
provisioning C.R.U.D (Create Retrieve Modify & Delete) operations but
add additional use case contexts like "SSO" as it is designed to
capture a class of use case that makes sense to the actor requesting
it rather than to describe a protocol operation.
o Create SCIM Identity Resource - Service On-boarding Trigger: A
create SCIM resource trigger is a service on-boarding activity in
which a business action such as a new hire or new service
subscription is initiated by one of the SCIM Actors. In the
protocol itself, service on-boarding may well be implemented via
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the same resource PUT method as a service change. This is
particular to the implementation not to the use cases that drive
that implementation.
o Update SCIM Identity Resource - Service Change Trigger: An Update
SCIM resource trigger is a service change activity as a result of
an identity moving or changing its service level. An Update
Identity trigger might be the result of a change in a service
subscription level or a change to key identity data used to denote
a service subscription level. Password changes are specifically
called out from other more general identity attribute changes as
they are considered to have specific use case differences.
o Delete SCIM Identity Resource - Service Termination Trigger: A
delete SCIM resource trigger represents a specific and deliberate
action to remove an identity from a given SCIM service point. At
this stage it is unclear if the SCIM protocol needs to identify
separate protocol exchange for a service suspension actions. This
may be relevant as target services usually differentiate between
these result and may require separate resource representations as
a result.
o Single-Sign On (SSO) Trigger - Real-time Service Access Request: A
SSO trigger is a special class of activity in which a Create or
Update trigger is initiated during an SSO operational flow. The
implication here is that as the result of a real-time service
access request by the end user (SSO), defined SCIM protocol
exchanges can be used to initiate SCIM resource CRUD somewhere in
the service cloud.
2.2.2. Actors
Actors are the operating parties that take part in both sides of a
SCIM protocol exchange, and help identify the source of a given
Trigger. So far, we have identified the following SCIM Actors:
o Cloud Service Provider (CSP): A CSP is the entity operating a
given cloud service. In a SaaS scenario this is simply the
application provider. In an IaaS or PaaS scenario, the CSP may be
the underlying IaaS/PaaS infrastructure provider or the owner of
the application running on that platform. In all cases, the CSP
is the thing that holds the identity information being operated
upon. Put another way, the CSP really is the service that the
end-end user interacts with.
o Enterprise Cloud Subscriber (ECS): An ECS represents a middle-tier
of aggregation for related identity records. In one of our sample
enterprise SaaS scenarios, the ECS is "FooBar.Inc" that subscribes
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to a cloud based CRM service "SaaS-CRM.Inc" (the CSP) for all of
its sales staff. The actual Cloud Service Users (CSUs) are the
FooBar.Inc. sales staff. The ECS actor is identified to help
capture use cases in which a single entitle is given
administrative responsibility for other identity accounts. SCIM
may not address the configuration and setup of an ECS within the
CSP, but it does address use cases in which SCIM identity
resources are grouped together and administers as part of some
broader agreement or operational exchange.
o Cloud Service User (CSU): A CSU represents the real cloud service
end-end user - the "person logging into and using the cloud
service". As described above, and ECS will typically own or
manage multiple CSU identities where as the CSU represents the
FooBar.Inc. employee using the cloud service to manage their CRM
process.
+---------------------+
| Cloud Service |
| Provider (CSP) |
+---------------------+
|
+--------------------------------+
| |
v v
+----------------+ +----------------+
|Enterprise Cloud| |Enterprise Cloud|
|Subscriber (ECS)| |Subscriber (ECS |
+----------------+ +----------------+
| |
+----------------+ +----------------+
| | | |
v v v v
+-------------+ +-------------+ +-------------+ +-------------+
|Cloud Service| |Cloud Service| |Cloud Service| |Cloud Service|
| User (CSU) | | User (CSU) | | User (CSU) | | User (CSU) |
+-------------+ +-------------+ +-------------+ +-------------+
Figure 1: SCIM Actors
2.2.3. Modes & Flows
Modes identify the functional intent of a data-flow initiated in a
SCIM scenario. The modes identified so far are 'push' and 'pull'
referring to the fact of pushing data to, or pulling data from an
authoritative identity data store.
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In the SCIM scenarios, Modes are often used in the context of a flow
between two Actors. For example, one might refer to a Cloud-to-Cloud
Pull exchange. Here one Cloud Service Provider (CSP) is pulling
identity information from another CSP. Commonly referenced flows
are:
o Cloud Service Provider to Cloud Service Provider (CSP->CSP)
o Enterprise Cloud Subscriber to Cloud Service Provider (ECS-CSP)
Modes & flows simply help us understand what is taking place; they
are likely to be technically meaningless at the protocol level, but
again they help the reader follow the SCIM scenarios and apply them
to real work use cases.
2.2.4. Bulk & Batch Operational Semantics
It is assumed that each of the triggers action outlined in this
document may be part of the larger bulk or batch operation.
Individual SCIM actions should be able to be collected together to
create single protocol exchanges.
The initial focus of SCIM scenarios is on identifying base flows and
single operations. The specific complexity of full bulk and batch
operations is left to a later version of the scenarios or to the main
specification.
2.3. Cloud Service Provider to Cloud Service Provider Flows (CSP->CSP)
These scenarios represent flows between two Cloud Service Providers
(CSPs). It is assumed that each CSP maintains an Identity Data Store
for its Cloud Service Users (CSUs). These scenarios address various
joiner, mover, leaver and JIT triggers, resulting in push and pull
data exchanges between the CSPs.
2.3.1. CSP->CSP - Create Identity (Push)
In this scenario two CSPs (CSP-1 & CSP-2) have a shared service
agreement in place that requires the exchange of Cloud Service User
(CSU) accounts. CSP-1 receives a Create Identity trigger action from
its Enterprise Cloud Subscriber (ECS-1). CSP-1 creates a local user
account for the new CSU. CSP-1 then pushes the new CSU joiner push
request down-stream to CSU-2 and gets confirmation that the account
was successfully created. After receiving the confirmation from
CSP-2, CSP-1 sends an acknowledgement to the requesting ECS.
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2.3.2. CSP->CSP - Update Identity (Push)
In this scenario two CSP's (CSP-1 & CSP-2) have a shared service
agreement in place that requires the exchange of Cloud Service User
(CSU) accounts. The Enterprise Cloud Subscriber (ECS-1) has already
created an account with CSP-1 and supplied a critical attribute
"department" that is used by CSP-1 to drive service options. CSP-1
then receives an Update Identity trigger action from its Enterprise
Cloud Subscriber (ECS). CSP-1 updates its local directory account
with the new department value. CSP-1 then initiates a separate SCIM
protocol exchange to push the mover change request down-stream to
CSP-2. After receiving the confirmation from CSP-2, CSP-1 sends an
acknowledgment to ECS-1.
2.3.3. CSP->CSP - Delete Identity (Push)
In this scenario two CSPs (CSP-1 & CSP-2) have a shared service
agreement in place that requires the exchange of Cloud Service User
(CSU) accounts. CSP-1 receives a Delete Identity trigger action from
its Enterprise Cloud Subscriber (ECS-1). CSP-1 suspends the local
directory account for the specified CSU account. CSP-1 then pushes a
termination request for the specified CSU account down-stream to
CSP-2 and gets confirmation that the account was successfully
removed. After receiving the confirmation from CSP-2, CSP-1 sends an
acknowledgment to the requesting ECS.
This use case highlights how different CSPs may implement different
operational semantics behind the same SCIM operation. Note CSP-1
suspends the account representation for its service where as CPS-2
implements a true delete operation.
2.3.4. CSP->CSP - SSO Trigger (Push)
In this scenario two CSPs (CSP-1 & CSP-2) have a shared service
agreement in place that requires the exchange of Cloud Service User
(CSU) accounts. However, rather than pre-provisioning accounts from
CSP-1 to CSP-2, CSP-1 waits for a service access request from the end
Cloud Service User (CSU-1) before issuing account creation details to
CSP-2. When the CSU completes a SSO transaction from CSP-1 to CSP-2,
CSP-2 then creates an account for the CSU based on information pushed
to it from CSP-1.
At the protocol level, this class of scenarios may result in the use
of common protocol exchange patters between CSP-1 & CSP-2.
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2.3.5. CSP->CSP - SSO Trigger (Pull)
In this scenario two CSPs (CSP-1 & CSP-2) have a shared service
agreement in place that requires the exchange of Cloud Service User
(CSU) accounts. However, rather than pre-provisioning accounts from
CSP-1 to CSP-2, CSP-2 waits for a service access request from the
Cloud Service User (CSU-1) before initiating a Pull request to gather
information about the CSU sufficient to create a local account.
At the protocol level, this class of scenarios may result in the use
of common protocol exchange patterns between CSP-2 & CSP-1.
2.3.6. CSP->CSP - Password Reset (Push)
In this scenario two CSPs (CSP-1 & CSP-2) have a shared service
agreement in place that requires the exchange of Cloud Service User
(CSU) accounts. CSP-1 wants to change the password for a specific
Cloud Service User (CSU-1). CSP-1 sends a request to CSP-2 to reset
the password value for CSU-1.
At the protocol level, this scenario may result in the same protocol
exchange as any other attribute change request.
2.4. Enterprise Cloud Subscriber to Cloud Service Provider
Flows(ECS->CSP)
These scenarios represent flows between an Enterprise Cloud
Subscriber (ECS) and a Cloud Service Providers (CSP). It is assumed
that both the ECS and the CSP maintains an LDAP service for the
relevant Cloud Service Users (CSUs). These scenarios address various
joiner, mover, leaver and JIT triggers, resulting in push and pull
data exchanges between the ECS and the CSP.
Many of these scenarios are very similar to those defined in the
Cloud Service Provider to Cloud Service Provider section above. They
are identified separately here so that we may explore any differences
and might emerge.
2.4.1. ECS->CSP - Create Identity (Push)
In this scenario an Enterprise Cloud Subscriber (ECS-1) maintains a
service with a Cloud Service Provider (CSP-1) that requires the
sharing of various Cloud Service User (CSU) accounts. A new user
joins ECS-1 and so ECS-1 pushes an account creation request to CSP-1,
supplying all required base SCIM schema attribute values and
additional extended SCIM schema values as required.
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2.4.2. ECS ->CSP - Update Identity (Push)
In this scenario an Enterprise Cloud Subscriber (ECS-1) maintains a
service with Cloud Service Provider (CSP-1) that drives service
definition from a key account schema attribute called Department.
ECS-1 wishes to move a given CSU from Department A to Department B
and so it pushes an attribute update request to the CSP.
2.4.3. ECS ->CSP - Delete Identity (Push)
In this scenario an Enterprise Cloud Subscriber (ECS-1) maintains a
service with a Cloud Service Provider (CSP-1). Upon termination of
one of its employees' employment agreement, ECS-1 sends a suspend
account request to CSP-1 (Figure 1.4.3-1). One week later the ECS
wishes to complete the process by fully removing the Cloud Service
User (CSU) account and so it sends a terminate account request to
CSP-1.
2.4.4. ECS ->CSP - SSO Pull
In this scenario an Enterprise Cloud Subscriber (ECS-1) maintains a
service with a Cloud Service Provider (CSP-1). No accounts are
created or exchanged in advance. However, rather than pre-
provisioning accounts from ECS-1 to CSP-1, CSP-1 waits for a service
access request from the Cloud Service User (CSU-1) under the control
domain of ECS-1, before issuing an account Pull request to CSP-1.
3. Recommendations
The recommendation is to merge the user scenarios document into the
use case document as section 2.
4. Security considerations
TBD
5. IANA considerations
This Internet Draft includes no request to IANA.
6. Acknowledgements
Authors would like to thank Darran Rolls and Patrick Harding, most of
the texts in this document are taken from them.
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Thanks to Bert Greevenbosch for his review and feedback.
7. Informative References
[I-D.ietf-scim-api]
Drake, T., Mortimore, C., Ansari, M., Grizzle, K., and E.
Wahlstroem, "System for Cross-Domain Identity Management:
Protocol", draft-ietf-scim-api-00 (work in progress),
August 2012.
[I-D.ietf-scim-core-schema]
Mortimore, C., Harding, P., Madsen, P., and T. Drake,
"System for Cross-Domain Identity Management: Core
Schema", draft-ietf-scim-core-schema-00 (work in
progress), August 2012.
Author's Address
Kepeng LI
Huawei Technologies
Bantian
Shenzhen, Guangdong 518129
China
Email: likepeng@huawei.com
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