This document discusses RTI's Transport Services Segment (TSS) Reference Implementation, which is built on Connext DDS Cert and conforms to the FACE Safety Base Profile. It provides an overview of the TSS context within FACE, the Transport Services API, and the modular and configurable architecture of Connext DDS Micro and Cert. Connext DDS Cert is designed for safety-critical applications and its code is certifiable to DO-178C Level A, the most stringent safety standard, with reusable certification evidence.

1. Your systems. Working as one.
FACE Aligned Reference Platform:
RTI TSS Reference Implementation
built on Connext DDS Cert
Dave Stringer, RTI
April 2016

2. Contents
• FACE TSS
– Transport Services Segment Specification
• RTI TSS RI
– RTI FACE 2.1 TSS Reference Implementation
• Connext DDS Cert
– DO 178C Level A Product

3. TSS Context within FACE
• Data Model
– Central to FACE Architecture
– Captures Semantics
– Shared Data Model for all Applications
• Configuration
– Simple APIs assist in Portability
– Complexity resides in Configuration Data
• Conformance
– UoP – Unit of Portability
– UoP author to provide a UoP Data Model
– RTI TSS RI conforms to FACE Safety Base Profile

4. Transport Services API
• C++ API
• 8 + 1 Functions
– FACE::TS::Initialize(…)
– FACE::TS::Create_Connection(…)
– FACE::TS::Receive_Message(…)
– FACE::TS::Send_Message(…)
– FACE::TS::Register_Callback(…)
– FACE::TS::Unregister_Callback(…)
– FACE::TS::Get_Connection_Parameters(…)
– FACE::TS::Destroy_Connection(…)
– FACE::Read_Callback::send_event(…)

5. RTI TSS Reference Implementation
RTI TSS Type
Plugin
Config
Plugin
QoS
Plugin
Configuration Mgr
ConfigEntry
ConfigEntry
Config Entry
Connection Mgr
ConfigEntry
ConfigEntryConnection
Entry
Logger
Connext DDS Pro / Connext DDS Micro / Connext DDS Cert
FACE UoP
FACE TS API
DDS Databus
DDS RTPS

6. Connext DDS Micro & Cert
• Data-centric Pub-Sub middleware
– Loose coupling between data producers and data consumers
• Support resource constrained environments
– Require as little as 41KB RAM, 350-500KB library size
– Low CPU load (< 10%)
• Distributed as highly portable source code
– Known to run on at least 11 operating systems
– Supports bare metal with no OS
• Certified to DO-178C Level A
– Evidence is available
• Common interaction semantics regardless of IPC mechanism
– E.g., Shared memory, ARINC ports, UDP ockets
• Follow OMG DDS specification
– RTPS wire protocol compatible
– Peer-to-peer interoperability with other DDS implementations
– Subset of standard DDS API
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7. Modular and Configurable Architecture
User Application
DDS API Subset
Transport API
Base-line configuration
OS API Queue API Discovery API
Listeners
Reliability
Durability &
History
Other QoS
Optional
APIs
Compile-timeoptions
Fully Dynamic
Discovery
UDPv4 Linux
Mobile
Static Endpoint
Discovery
Plug-in components
Linear Queue
Keyed QueueShared
memory
RTOS
RTPS Windows
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8. Connext DDS Inherently Well-Suited to
Safety-Critical Systems
• Non-stop availability
– Decentralized architecture
– No single point of failure
– Support for redundant networks
– Automatic failover between redundant publishers
– Dynamic upgrades
• No central server or services
• Version-independent interoperability protocol
• Control over real-time Quality of Service
• Visibility into missed deadlines and presence
• Proven in thousands of mission critical systems
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9. High-Assurance Safety: DO-178C/ED-12C
• Guideline
• Used by FAA, EASA and
others to certify
airworthiness of civil
aircraft
• Also required for
integration of drones into civilian National Air
Space
• Generally acknowledged as most stringent
safety standard
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10. DO-178C Level A Certification Evidence
• Plan for Software Aspects of
Certification (PSAC)
• Software Development Plan (SDP)
– Requirements standards
– Design standards
– Code standards
• Software Verification Plan (SVP)
• Software Configuration
Management Plan (SCM)
• Software Quality Assurance Plan
• Software Requirements Data
• Design Description
• Traceability
• SQA Records
• SCM Records
• Software Configuration Index
• Software Verification Cases and
Procedures
• Software Verification Results
• Software Accomplishment
Summary
Certification evidence can be re-used across programs
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11. Connext DDS Cert Slashes Certification
Costs
• Minimizes code for which certification evidence
must be generated
– Eliminates custom connectivity code
– Rich capabilities reduce and simplify application logic
• Minimizes recertification effort as systems evolve
– Encourages modularity
– Decouples software modules and subsystems
– Isolates changes
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12. Summary
• RTI FACE 2.1 TSS RI
– Reference Implementation
– Builds on Connext DDS product family
– FACE OS Safety Base Profile
• Connext DDS Cert designed for safety-critical
applications
– Code is certifiable to DO-178C/ED-12C Level A
– Certification evidence is reusable
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