Space Communications Cross Support Architecture Working Group

					Space Communications Cross Support
    Architecture Working Group

                Action Item (Fall, 2008) #2:
   Relationship between the IOAG Cross Support Service
   Architecture White Book and the CCSDS Cross Support
                      Reference Model

                        Fred Brosi
                      February, 2009
       Action Item #2 from CSA-WG:



“Analyze the relationship between the IOAG Cross
  Support Service Architecture White Book and
  the CCSDS Cross Support Reference Model
  Green [actually, Blue] Book.”

Note: The draft IOAG Cross Support Service Architecture has become
  the initial draft of the CCSDS Cross Support Service Architecture
  White Book


                                                                      2
                       CSSA:SLE-RM
            CSSA                          SLE-RM
• Scope: Space                     • Scope: Cross-support
  communications cross               transfer & management
          1
  support                            services
• 4 Views:                         • 2 Views:
    –   Service                      – The RM Functional View is
    –   Physical                       roughly equivalent to the
    –   Communications                 CSSA Service View
    –   Enterprise                   – The RM Cross-support View
                                       has aspects of both the
                                       Physical and Enterprise
1
 –from the WG Charter. So should       Views
CSSA be SCCSA? Should CSA-WG
be SCCSA-WG?

                                                                   3
         SLE-RM Cross-support View
•   “The cross support view…provides the means to model allocation of
    the functions identified in the functional view to real systems under
    independent management authorities, which are named SLE
    Complexes. The cross support view also describes the management
    interactions between SLE Complexes and the SLE Utilization
    Management on behalf of the MDOS.”
• RM’s implied physical view is:
     – Space element and ground element are physically separated
• RM’s implied enterprise view is:
     – The ground element components (SLE System and MDOS) may
       be physically separated, but are assumed to belong to different
       organizations
     – The SLE System that supports a mission comprises one or more
       SLE Complexes, which may be physically separated, but are
       assumed to belong to different organizations (or, at least, the
       MDOS must arrange services with each separately)
• These concepts could be modeled easily using CSSA.
                                                                        4
            SLE-RM Functional View
•   “The functional view…defines the functions (and their management)
    that may be performed by an SLE system, without regard to the way
    these functions are allocated to various management authorities in
    real systems. The functional view decomposes the SLE system into
    elementary functions, called SLE Functional Groups (SLE-FGs), that
    transfer and deliver return and forward data between the space
    element and the [mission users].”
•   “Each SLE-FG performs a related set of functions that provide one
    or more related SLE transfer services.”

•   The SLE-RM Functional View could be expressed as a Service View
    under CSSA.




                                                                     5
     CSSA, SLE-RM, and other Space
   Architectures and Reference Models
• CSSA–Space Communications Cross Support
  Architecture
• SLE-RM SLE–Cross Support Reference Model
• RASDS–Reference Architecture for Space Data
  Systems
• NASA SCaN ADD–Integrated Network
  Architecture Definition Document
• SISG Report–Recommendations on a Strategy
  for Space Internetworking

                                                6
                                     Views
                                                        SCaN         IOAG
          View              RASDS         CSSA          ADD          SISG         SLE-RM
                                                                                            1
  Enterprise View              X             X            X             X               X


  Functional View              X                                                        X
       Service View                          X            X             X



                                                                                            1
   Physical View                             X            X             X               X
 Connectivity View             X



Communications View            X             X            X             X


  Information View             X


  Operations View                                         X

   1
    The SLE RM defines a “Cross-support View” that is essentially an Enterprise View,
   but includes some aspects of a Physical View.
                                                                                                7
                             Scope
•   RASDS–is intended to describe data system architectures and
    designs within the space domain
•   CSSA–to be used as a common framework when IOAG Agencies
    provide and use space communications cross support services
    and develop systems that provide cross support services
•   NASA SCaN ADD–describes the services and capabilities to be
    provided by the SCaN integrated network architecture for the time
    period 2009-2025, and the progression of the current
    architecture toward achievement of the target architecture.
•   IOAG SISG–space internetworking and international
    interoperability at the Network layer of space communications.
    The functionality of the Network layer of the ISO OSI
    communications stack, including its dependencies and effects on
    lower and higher layers.
•   SLE-RM–provides a common basis for coordinating the
    development of CCSDS Recommended Standards for Space Link
    Extension (SLE) service specifications
                                                                        8
          Scope: RASDS, CSSA, and SLE-
                      RM
                                                                  RASDS
   Interoperable Spacecraft               CSSA
   Onboard Interfaces                                         Space Data Systems
                              Space communications
                                     Systems



                                          SLE-RM
                                Station-to-Mission Cross
Highly Efficient                        -support:
Communications in              SLE-Transfer (CSTS) & Cross-
Resource-Constrained           support Management Services
Environments



                                          Standard Data Interchange
                                          and Archiving Services




                                                                               9
Scope: RASDS, CSSA, and SLE-RM


                                      RASDS: Space
                                      Data Systems



                                                     Application
                                                       Layer
    SLE-RM: Station-to-Mission Cross-support




                                                     Network
                                                      Layer



                                                     Link Layer

              CSSA: Space Communications Systems


                                                               10
Scope: RASDS, CSSA, SLE-RM, IOAG SISG, and NASA SCaN ADD
                IOAG Agencies                     Non-IOAG Agencies

     ASI        CNES      …        NASA             BNSC      …
                                                              RASDS: Space
                                                              Data Systems


                                                                       Application
                                                                         Layer

                   SLE-RM: Station to Mission Cross-support


 IOAG SISG: Space Internetworking – Layer 3
                                                                         Network
                                                                          Layer



                                                                        Link Layer
                              SCaN ADD
                 CSSA                         Space Communications Systems


                                                                                   11
                           Enterprise View
•   RASDS Enterprise View
    – Purpose, scope, and policies for the space data system. Organizational entities
      and relationships; their roles, requirements, goals, objectives, scenarios,
      constraints; and how to meet them.
•   CSSA Enterprise View
    – Processes and rules governing the initiation, negotiation, and agreement
      between the supported and supporting Agencies for the provision of cross
      support services. Administrative and contractual aspects of the service
      architecture. (Policies, Documents, Pricing, Service agreement, interface testing
•   SCaN ADD Enterprise View:
    – Processes and rules governing the initiation, negotiation, and agreements
      between supported missions and provider networks for the provision of standard
      services and support; specifically addresses the administrative and contractual
      aspects of the service architecture
•   SISG Report Enterprise View
    – Organizational structure associated with space communications systems and
      scenarios and its administrative characteristics; physical and administrative
      interfaces between organizations; documents exchanged between organizations.
•   SLE-RM Enterprise (Cross-Support) View
    –   An SLE Complex is a set of SLE Functional Groups under a single management authority. At
        the time of cross support, an SLE complex has a single established relationship between the
        SLE system and the MDOS .

                                                                                                12
              Functional/Service View
•   RASDS Functional View
    – Functional decomposition of the space data system into abstract objects that
      interact at interfaces. It describes the functionality provided by the space data
      system, the behavior of the functional elements, and their functional
      decomposition.
•   CSSA Service View
    – Services provided by cross support service systems/elements, their functional
      and performance characteristics, and methods and/or standards for using and
      managing services.
•   SCaN ADD Service View:
    – The proposed repertoire of standard service offerings that SCaN networks
      provide to flight missions, including a functional description of each service type,
      and the service management function processes that flight missions use to
      obtain, specify, access, and use SCaN services.
•   SISG Report Service View
    – Services (which are functions provided by some physical elements for other
      physical elements), their functional and performance characteristics, and
      methods and/or standards for using and managing services.
•   SLE-RM Functional View
    – Functions that provide SLE transfer services, implemented by SLE-Functional
      Groups (FGs). Each SLE-FG performs a related set of functions that provide one
      or more related SLE transfer services.

                                                                                          13
           Physical/Connectivity View
•   RASDS Connectivity View
    – the decomposition of the space data system into components (nodes) that
      interact across connectors (links). Describes the physical aspects of the space
      data system and the external environment within which it operates, the physical
      behavior (and motion) of the nodes, and their physical decomposition.
•   CSSA Physical View
    –    The Physical View is used to describe the physical configuration of cross
        support service systems/elements and their physical characteristics: physical
        location; topology and connectivity; and physical media for access.
•   SCaN ADD Physical View:
    – physical description of the SCaN integrated network architecture assets as they
      change over incremental timeframes ending in 2015, 2020, and 2025; includes
      physical location, topology and connectivity, and functional and performance
      attributes.
•   SISG Report Physical View
    – The Physical View is used to describe the physical configuration of cross support
      service systems/elements and their physical characteristics: physical location;
      topology and connectivity; and physical media for access.
•   SLE-RM Physical (Cross-Support) View
    – Physical systems that interoperate to provide SLE services to a space mission
      may be independently operated by different Agencies or by different
      organizational elements within an Agency. In the cross support view, each such
      physical system is modeled as an SLE Complex .
                                                                                        14
              Communications View
•   RASDS Communications View
    – The mechanisms and functions required to engineer and implement the
      protocols and communications standards for the space data system,
      including implementation choices and specifications, and allocation of
      communications functionality to engineered components of the system.
•   CSSA Communications View
    – The communications protocols used for accessing services provided by
      cross support service systems/elements and the parameter values of
      communications protocols .
•   SCaN ADD Communications View:
    – Protocols and standards employed to provide the end-to-end
      communications in support of SCaN services, including the protocol
      parameter values or types.
•   SISG Report Communications View
    – The communications protocols and modulation/coding methods used
      between physical elements and their communicational characteristics,
      and the parameter values of communications protocols.
•   SLE-RM Communications View
    – N/A.
                                                                             15
                   Other Views
• Information View
  – RASDS: information handled by the system, the
    semantics of the information, and the interpretation of
    that information. It describes the information managed
    by the space data system along with the structure,
    content, semantics, type, relationships, and
    constraints on the data used within the system.
• Operations View
  – SCaN ADD: scenarios describing the operational
    activities that will be conducted by the networks, and
    in some cases, the supported flight missions.

                                                             16

				
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