1. M2M Service Session Management (SSM) CSF
Group Name: WG2-ARC
Source: IDCC, LGE, ZTE
Meeting Date:
Agenda Item: CSF Definitions

2. Outline M2M Service Session Requirements
Definition of M2M Service Session
M2M Service Session Use Case Examples
Role of M2M Service Session Management (SSM) CSF
Describe SSM CSF capabilities
Describe relationship with other CSFs
Show some Stage-2 message flows
Show SSM resources

3. Requirements
OSR-003
The M2M System shall support the ability to maintain M2M Session in coordination with application session for those M2M Applications that require it.
OSR-004
M2M System shall support the ability to support session-less application communications for those M2M Applications that require it.
CRPR-005
The M2M System shall be able to maintain context associated with M2M sessions (e.g. security context or network connectivity context during the interruption of the session).
Source: oneM2M-TS-0002-Requirements-V0_6_2

4. Definition
“M2M Session: A service layer communication relationship between endpoints managed via M2M Common Services consisting of session authentication, connection establishment/termination, transmission of information, and establishment termination of Underlying Network services”
Source: oneM2M-TR-0004-Definitions_and_Acronyms-V
oneM2M-TP

5. Use Case #1 – Real-Time Audio/Video
M2M service session endpoints AE1 and AE2 exchange real-time audio/video commands & data
CSEs manage end-to-end real-time service session between AEs (e.g. establishment/termination), communication,…)
Service session overlaid on top of multiple underlying network connections (i.e. for each hop)
Service session is persistent w.r.t. underlying network connections
CSEs use AE defined session policies to coordinate end-to-end QoS required by AE1 and AE2
CSEs collect service session context (e.g. history of prior requests)
CSE can use context and also make it available to AEs
Mcc
Infrastructure Node
Middle Node
Application Service Node
CSE2
CSE3
CSE1
Mca
AE1
Without M2M service session, AEs lack sufficient capability to configure end-to-end communication policies and CSEs lack capability to effectively manage end-to-end communication.
AE2
Mca

6. Use Case #2 – Real-Time & Secure Health Monitoring
M2M service session endpoints AE1 and AE2 exchange real-time and secure patient vital signs
CSEs manage end-to-end real-time and secure service session between AEs
CSE-based registration enables securing individual single hops between CSEs and AEs
Service session enables securing end-to-end multi-hop exchange of patient vital signs
Traditionally, the burden of securing end-to-end communication has fallen on the AEs
E.g. Over-the-top AE-based end-to-end authentication and encryption
Service sessions can help offload burden from AEs while not compromising security and also enable additional value-add CSE services that are not possible with over-the-top AE-based security (data centric services such as analytics, semantics, etc)
Without M2M service session, oneM2M service platform lacks services to support end-to-end security. This puts the end-to-end security burden on AEs and also limits the type of services CSEs can offer.
Mcc
Infrastructure Node
Middle Node
Application Dedicated Node
CSE1
CSE2
Mca
AE1
AE2
Mca

7. SSM CSF
SSM CSF manages M2M service session establishment, communication, and termination.
SSM CSF enforces service session communication policies, collects and maintains service session context, and generates service session events.
Note – For use cases that do NOT require a service session, SSM CSF will not be used.

8. SSM CSF Capabilities
Service session authentication, establishment and termination
Collect and maintain service session context/history
E.g. Keep history of transactions between session endpoints
Manage service session policies
E.g. SSM can use policies to configure CMDH on a per-session basis
Manage sessions spanning multiple hops of CSEs
Coordinate and distribute service session policies end-to-end to each SSM on each CSE along a multi-hop path
Likewise, collect/exchange service session context end-to-end
Coordinate with other CSFs to support service sessions
E.g. CMDH, SEC, NSE, SCA, etc
E.g. Collaborate with NSE and CMDH to manage underlying network connections and services required for end-to-end service session

9. Service Session Establishment
AE1
CSE1
CSE2
CSE3
AE2
AE1 Registers CSE1
AE2 Registers CSE3
Request to Establish M2M Service Session
(Session policies, Target endpoint(s) – ‘AE2’, Other attributes,…)
FWD the Request to CSE(s) where the Target Endpoint(s) is registered
Notify the Request
Request to Join the M2M Service Session
FWD the Join Request
Determine M2M-Session-ID
and Session Credentials
Response
(M2M-Session-ID,
Session Credentials, …)
Response
(M2M-Session-ID,
Session Credentials, …)
M2M Service Session is successfully established

10. SSM CSF Example Middle Node Mcc Infrastructure Node CSE2 CSE1 Mca CMDH
AE1 establishes service session via CSE1 and configures session communication policies, etc.
AE2 joins service session via CSE2/CSE1
During this process, SSM on CSE2 is configured with session info from SSM on CSE1
AE2 sends session-based request to AE1 resources via CSE2 and CSE1
CSE1 can host AE1 resources and service requests on behalf of AE1, or
CSE1 can re-target requests to resources hosted on AE1 that AE1 can service itself
SSMs on CSE1 and CSE2 service requests and responses in a session-based manner
E.g. SSMs collaborate with CMDHs to configure delivery parameters based on session policies
Service session-based communication
between AEs
Middle Node
Mcc
Infrastructure
Node
Application Dedicated Node
CSE2
CSE1
Mca
CMDH
AE1
Application Dedicated Node
DMR
DMR
Mca
AE2
SSM
SSM
NSE
NSE

11. Session-Based Request
M2M-Session-ID = X
M2M-Request-ID = Y …
Service Session-based requests can optionally be encrypted using service session-based credentials
Note – Need to consult with SEC WG to further explore this.
Note – Association between M2M-Session-ID and M2M-Request-ID is FFS

12. Relationship between SSM & CMDH
CMDH CSF
Supports policy-based delivery of individual M2M requests between CSEs
Each request has its own independent M2M-Request-ID and delivery parameters
CMDH provides communication connection controls
Like ISO network model layer 4 functions
SSM CSF supports policy-based delivery of a stream of session-based requests over top of CMDH policy-based delivery of individual M2M requests (CMDH provides bearer-like mechanism for SSM)
Like ISO network model layer 7 functions, e.g. SIP - SSM handles the session related capabilities which is based on underlying CMDH based connections
Requests from the same service session share the same M2M-Session-ID and delivery parameters. This allows SSM CSF to manage these requests in a session-based manner.
SSM CSF is a customer of CMDH CSF. SSM CSF uses session-based policies to configure CMDH delivery parameters so requests are delivered in a manner that meets the session requirements.
SSM also collects/maintains service session context and generates service session events based on the service session requests it services which CMDH is not able to do since it is not aware of sessions.
Note - Some non-service-session based CSFs do not need SSM and can invoke CMDH directly.

13. Relationship between SSM & CMDHAE AE AE
Mca
CSE
Other CSFs
non-service-session based communication request
service-session based communication request
DMR
SSM(service sessions mgmt.)
Mcc
CMDH (Communication Management and Delivery Handling)
Mcn
NSE(Underlying Network Services Entity )

14. Relationship With Other CSFs
REG CSF
REG CSF supports an AE or CSE registering to a local CSE to use its M2M services
REG CSF-based registration is single-hop in nature
SSM CSF supports establishing communication relationships between AEs and/or CSEs layered over top of REG CSF M2M registration(s)
Service session can be multi-hop and end-to-end in nature
DMR CSF
SSM CSF collaborates with DMR CSF to service session based requests targeting CSE hosted resources
SEC CSF
SSM CSF may collaborate with SEC CSF for management of service session related security credentials and authentication of session participants
NSE CSF
SSM CSF may collaborate with the NGE CSF for establishment termination of Underlying Network services to support service session
This may be indirectly via CMDH
SCA CSF
SSM CSF may share service session context and events with SCA CSF

15. Next Steps and Open Items
Reach clear consensus on SSM concept and capabilities
Based on approved use cases and requirements
Reach rough consensus on SSM relationship with other CSFs
Define SSM resources and procedures
Open Items
Detail relationship between SSM and other CSFs
SSM interaction with SEC
Service session credentials, authentication, encryption, threats, etc