SDL Language Relevance to Protocol/Telecom Application Development: Case Study

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SDL Language Relevance to Protocol/Telecom
Application Development Case Study
By Bhaskar Rao.G, Software Engineering
Group, Motorola India Electronics Pvt.
Ltd., Bangalore, India- 560 042
World of Communication
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SDL, Is it only Auto Code Generation?

• Integrated Methods and Tools for Software
  Development (Methodology)
• Requirements - MSC
• SAD - State Charts/UML/SDL
• Coding - SDL, C ltAUTO CODE gt
• Unit and Integration Testing - Simulation
  Validation
• System Testing - TTCN/SDL
• Code generation for multiple targets pSOS, Vrtx,
  VxWorks, NT, UNIX, Classic, OSE etc
• Separates Functionality from Implementation and
  Environmental aspects
• Design, Implementation and Test Development (with
  environment) language

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Product development with SDL
Req Analysis
System analysis and design
Object design
Verification and Validation
Auto code generation
System testing
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MIEL Projects

• Infrastructure projects
• Control Network projects
• Other Projects

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Benefits of using SDL at MIEL

• Average test effort for SDL projects reduced due
  to V V
• No noticeable performance overhead
• SDL Based test automation was very effective
• Unit, Integration, Load, Conformance and
  Performance testing
• Less dependency on tools, Good Environment
  support
• Auto code is Scalable

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Major Concerns

• Technical Concerns
• Impact on Code Size Performance ltLack of
  effective code generators Hand-written codegt
• Data Handling Problems ltAddressed in SDL-2000gt
• No Support for Global Data and No effective ways
  to write Algorithms
• Difficulty in Understanding Auto Generated Code
  ltSDL to be maintainedgt
• Managerial Concerns
• Familiarity with Current Practices ltLearning
  Curvegt
• Estimation and Tracking need improvement lt New
  approachgt
• Cost of the tools
• Customer Related
• Not Willing
• Other Modules are in C ltC code integration
  External proceduresgt
• On Site Maintenance
• Timely Delivery due to projected risk of using
  new technology ltNot a Risk, Fastergt

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Challenges ahead

• Good and Effective Code Generators
• Code size and Performance
• Direct executable instead of code generation
• SDL-2000 supporting tools
• Gap between the standard and implementation
  should be small
• Portable across tools
• Enhancing the SDL to support General Application
  Development
• Cost considerations

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Case Study
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Specifications Data Link Layer

• The Data Link Layer shall get packets from the
  Network Layer, Thease packets have to be
  segmented and converted Frames and sent to the
  Physical Layer
• Does Framing and Error Control
• Note Please Refer to ISO-OSI specs for the
  detailed specifications

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Interaction with the environment
Environment
System
Ack, Nack
Packet
L2
L3, L1
L3Chnl
L2Chnl
Frame
FrAck
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Simplified FSM for L2
Init
Start
Idle
Packet/Call BreakN_SendM_Timer(N)
FinalAckFrame/Ack
WaitRsp
TimeOut/Retransmit
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SDL System Architecture
SignalsPack
DataDefPack
E N V I R O N M E N T
E N V I R O N M E N T
External C Code
System
BlockType
Block 1
ProcessType
Process 1
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V V
Test Engineer
Test Data
SDL Simulator ltSystemgt
Traces SDL MSC Text Breakpoints
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Application Integration
Other Applications
Glue Logic
Generated Application (Single Thread)
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Application Integration
Other Applications
Glue Logic
Generated Application (Multi-Threaded)
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Conclusions

• SDL Suitability and Promises
• Application Perspectives
• Product Development Process
• Case Study

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Q A

• Bhaskar Rao.G
• gbr_at_miel.mot.com
• 91-80-5598615 ext 3091
• Motorola India Electronics Pvt Ltd,
• Banglore- 506 042

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Backup Slides
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SDL Promises

• Facilitates Development of the Product from
  Requirements to End
• MSC, UML(State Charts), SDL, TTCN, Simulation,
  Validation, Auto code, Auto Test Case generation
  .
• Separates Functionality from Implementation and
  Environmental aspects
• Designs captured at higher levels of abstraction
• Verification of functionality (Make sure it is
  correct)
• Specialization to a particular environment and
  platform
• Code generation for multiple targets
• pSOS, Vrtx, VxWorks, NT, UNIX, Classic, OSE etc
• Re-targeting 2-3 staff months effort (ONE TIME)
• Integrated approach with integrated methods

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SDL Promises (2)

• Graphical Representations
• Availability of major implementation concepts as
  primitive types in the language
• Timers
• Messaging
• State Machine
• Sending and Receiving
• Structuring mechanisms
• Targeting specifications
• Entire system as task
• Multiple tasks
• OS and NON OS communicating mechanisms

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Usage Perspectives of SDL

• Design language
• Used as primarily the design language to capture
  high-level details
• Telecom, Real Time and major protocol
  development
• Implementation language (with code generation)
• SDL, MSC, TTCN, Simulation, Verification, Code
  Generation, C ...
• Completely formal SDL representation
• Takes extra 30 effort
• Minimizes the need for extra coding phase
• Early verification and validation

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Usage Perspectives of SDL (2)

• Test case development language
• Proved to be very good for medium and high
  complex systems
• Unit, Integration, Performance, Conformance,
  Stress testing
• Features enable suitability
• FSM, Timers, Messaging, Logging, Tracing and
  Reply with tool
• Concurrency
• Ability to simulate the non-existing modules

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SDL Deployment at MIEL

• The SDL methodology at MIEL uses integrated
  methods and tools for protocol stack software
  development
• Requirements - MSC
• System Analysis and Design - State Charts/SDL
• Coding - C, SDL (Code Generation)
• Unit and Integration Testing - Simulation
  Validation
• System Testing - TTCN/C
• Not used for incremental changes to legacy
  products

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Requirements Analysis

• Importance levels
• Critical, Medium, Low
• Separate guidelines to be followed
• Effectiveness of the code generator
• implementation/Design aspects influence the
  performance and code size

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VV

• Discrete, Real Time and Remote target simulation
• Validation of MSCs
• Automatic detection of deadlocks and dynamic
  errors
• Generation of MSCs

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Code Generation Environment
Run Time Library UNIX, NT, pSOS, VxWorks,
SDT Auto Code Tool
SDL Code
Gen. code
Compiler
SDT Simulation
H2SDL
Executable
C Headers
Manual C Code
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Case Study
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Problem Solving Stages

• Requirement Analysis
• MSCs are helpful
• Interface Specification
• State Charts
• System Analysis and Design
• HLD with SDL
• LLD
• Detailed SDL and C code
• Logging
• Simulation
• Verifying the correctness wrt to Requirements
• Code Generation and Application Build

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HLD

• Environment
• Network Layer, Physical Layer
• Data structures
• Packet, Frame and other internal data structures
• Timers
• A timer (set) is required for very frame
• Messages
• Packet, Frame, Ack, Negative Ack

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Issues

• Application Building
• Separate Application, Part of the application,
  Part of the existing application, Run on a
  particular target, Multi Threading VS Single
  Threading
• Process
• Estimations and Actuals
• Cycle Time, IPF, Productivity
• Tracking and Controlling issues
• Lack of sufficient data
• Maintenance
• Adding New Features, Corrections, Changing the
  implementations