6 Verification of Protocol Using SDT

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?? 6 Verification of ProtocolUsing SDT
TE523/EE525 ????????

• SeYoung Yun
• syyun_at_comis.kaist.ac.kr

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Contents
01 Specification and Description Language
(SDL) 02 Point-to-Point Protocol (PPP) 03
Prelab 04 Mainlab
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Specification and Description Language (SDL)
Overview

• International standard by ITU-T
• Characteristics of SDL
• Object-oriented language
• Message based description
• Complete operational semantics and execution
  model
• Independent of implementation language
• Systems can be realized in both software and
  hardware
• Graphical and textual representation
• SDL-PR (Phrasal Representation) textual syntax
  only
• SDL-GR (Graphical Representation) graphical
  component textual part
• SDL is based on FSM (Final State Machine), and
  each State is defined to receive and transmit
  signals at any time.

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SDL Basic components

• Main hierarchical components
• System
• Block
• Process
• Procedure
• Signal and channel
• Complete specification
• A system must have at least a block specification
• Pre-defined types are to be defined at system
  level

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SDL Basic configuration

• Basic configuration

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SDL Data-types (1/2)

• Pre-defined Data Type
• Integer, Real, Boolean, Character, Charstring,
  Time, Duration, etc.
• Declaration of variables
• dcl ltvar namegt type ltexpressiongt
• Examples
• dcl x1, x2 Integer
• dcl bt Booleantrue
• dcl str CharstringThis is string

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SDL Data-types (2/2)

• Structure
• User-defined data type
• newtype Person struct
• nm Charstring
• nr Integer
• fm Boolean
• endnewtype Person
• ANY( )
• Returns any value of specified data type.
• anyInteger ANY(Integer)
• Timer
• Timer x
• SET(x) start, RESET(x) stop

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SDL SDL Design Tool (SDT)

• Real-time software development tool
• Based on Object-oriented design language SDL
  Trace language MSC
• Components
• Code generator
• Graphical editor
• Syntax analyzer
• Simulator with MSC
• Optimized code generators

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Point-to-Point Protocol (PPP)

• PPP
• PPP is communication protocol for using direct
  interface
• In general used in WAN, particularly used by PC
  to connect to sever via telephone line

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Point-to-Point Protocol (PPP)

• PPP frame format

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PPP Link Control Protocol (LCP)

• LCP 4 steps
• First, LCP open connection and negotiate
  configuration parameters
• Second, LCP decide optional link condition. In
  this step, check that link condition is enough to
  send network layer protocol.
• Third, NCP negotiate Network-layer protocol
  configuration.
• Fourth, Link closed
• By user request or physical problem

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PPP Link Control Protocol (LCP)

• Events and Actions

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PPP Link Control Protocol (LCP)

• State transition table

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PPP Link Control Protocol (LCP)

• Code of LCP packets
• Configure-Request, Configure-Ack, Configure-Nack,
  Configure-Reject, Terminate-Request,
  Terminate-Ack
• Option field in Configure-Request LCP Packet

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Prelab

• Explain the reason that data link protocol uses
  timers and the problem generated when data link
  protocol only uses timers. And propose new method
  to solve this problem.
• Copy example program file, basic, in your
  license folder and simulate using SDT. Add next
  operations. And simulate your new program and
  submit the results and MSC files.
• Make Channel Block between Transmitter and
  Receiver Blocks. Data and Ack signals pass on
  this block before arriving at Transmitter of
  Receiver Block.
• Make control signal by using Channel Block.
• Data to be dropped Xth Data that pass on this
  Block will be dropped
• ACK to be dropped Yth Data that pass on this
  Block will be dropped
• Input control signal like the form of (X,Y).
• By using control signal, Channel Block should
  drop Xth Data and Yth ACK.

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Prelab Example

• Example

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MainLab

• Validate verify the simplified LCP (Link
  Control Protocol) in PPP as followed. Include
  these factors at least.
• Process of link connection and disconnection
  between two peers.
• State transitions of the automaton in LCP layer
• Exchange of LCP packets between two peers
• Option of data field in Configure-Request
  packet
• 110 Config. Ack
• 1020 Config. Nack with option 1
• 2030 Config. Reject with transmitted option
  value
• Transmitter reduce the option value by one and
  retransmit Configure-Request Packet
• Identifier and Length field are not necessary.

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Notice

• account
• Server ctep-serv.kaist.ac.kr
• ID group0 (0112)
• Passwd group0 (01-12, change your password)
• SDT execution sdt