CCSDS Message Bus
Comparison
Shames, Barkley, Burleigh,
Cooper, Haddow
28 Oct 2010
Intent of these materials
• Present current descriptions of the four
current standards that define and/or use
message bus specifications
• Identify their specific features and
interfaces
• Compare the features and describe them
in the context of the standard ISO Stack
• Provide the basis for analysis of overlaps
and harmonization
SM&C Message Abstraction
Layer (MAL)
• Message layer BB (interoperable only in
combination with a data mapping and
technology binding), generalized message
structures, numerous interaction patterns
(client/server and message bus), abstract
service interface (and separate API spec),
extensible message structure framework,
transport agnostic (uses underlying
message bus, JMS, AMQP, DDS, AMS)
SM&C MAL Protocol Stack
SM&C Client/Server Application
MAL API
MAL Interaction Patterns
SM&C Message encoding layer
Transport adapter
Message bus (JMS, AMQP, DDS, AMS)
SM&C MAL Message population
stages
Populate MAL Message Header
Encode to Message Bus format
SM&C Message encoding layer
Populate MAL Message Body
Service Management (SM)
• Specific Service (BB) for service
management domain, application service
entity behavior and document exchange
protocol, specific set of client/server
message interchange patterns, service
message bindings to XML, transport
agnostic (SMTP & HTTP/SOAP bindings
to date)
SM Operation Procedures, Document Exchange Protocol,
and Underlying Communication Service, Fig 3-1
Information Services
Architecture (ISA)
• Reference Model (MB) & Service Binding
(BB) (Draft WB now) defines Registry
service, service interface, a few specific
message exchange patterns, specific
service messages and structures,
reusable/extensible information
framework, it is data transport agnostic,
using HTTP, JMS, and other methods
Representing the Information Service Architecture
(ISA) Logical Stack
•
•
•
a layered view of the CCSDSrelated services abstracting out
the messaging middleware, from
the information infrastructure
allows us to understand the
overlaps
CCSDS is involved in the
development of standards at each
of these levels
standards efforts should fit
together and CCSDS should be
mindful when standards effort
cross multiple boundaries in the
architectural model to ensure
interoperability remains as a
critical architectural tenet
Messaging Middleware
MAL /
AMS
HTTP /
JMS
Network Protocols /
Physical Layer
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AMS
• AMS – BB, interoperable protocol specification (PDU, state
machines) for generalized distributed messaging over long haul and
short haul links, several supported interaction modes (client/server
and message bus), & abstract AMS service interface, no specific
message content specifications
• AMS is a message bus system comprising three Application Layer
protocols
– Application AMS (AAMS) protocol conveys published application data
over a variety of transport protocols
– Meta-AMS (MAMS) protocol conveys AMS auto-configuration metadata
- enabling AAMS traffic flow - over one of those transport protocols
– Remote AMS (RAMS) protocol encapsulates AAMS messages in an
underlying delay-tolerant protocol (notionally, but not necessarily, the
DTN Bundle Protocol) for propagation across space links.
– So AAMS is typically a TCP or UDP application, MAMS is usually a
UDP application, and RAMS is a BP application.
AMS mapping to MAL
AMS BB Pg 2-5
Alignment with ISO
MAL
Application
Presentation
Session
[Middleware]
Transport
Network
Data Link
Physical
AMS
SM
ISA
SM&C MAL Protocol Stack
Client
Application
Provider
Application
SM&C MAL
SM&C MAL
Message bus
MAL Message definition
• Definition of the message body structure is
static and is specified as part of a service
definition.
• The message encoding is agreed before
hand and is an aspect of the deployment
• The population of the message header is
something that is performed at runtime.
ISA Notional Layers
•
Application – These are clients that leverage and use services and standard models.
They include domain specific models necessary for interoperability.
•
Application Services – These are CCSDS domain specific services which are
deployed into a SOA-style deployment. These include domain specific models
necessary for interoperability.
•
Infrastructure Services – These are standard information services and models which
support discovery and deployment of application services, information management
services, etc.
•
Messaging Services – This is the messaging layer which identifies protocols and
message structure necessary for applications to be deployed into a distributed
service architecture.
•
Network Layer – This is the communication layer. Construction of higher order
messaging and information/infrastructure services should be built on top of this layer.
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