1. Lab 1 – Synchronous communication (Physical Layer)
MPC8360 Computer Networks I
Lab 1 – Synchronous communication (Physical Layer)
Semester B, 2010

2. Lab Grading The Lab grading is 50% from the final course grade
Labs %
Quiz 5%
Haganot 10%
Final Report 5%
Final Quiz - 30%
Late arrival: Zero in lab quiz
Didn’t come to lab (for no good reason): -10 points from the course final grade

3. Layer III Network Layer
Syllabus
Lab
Subject
OSI Layer 1
Synchronous Communication
Layer I Physical Layer 2
Asynchronous Communication 3
Differential Pair
4,5
Ethernet introduction
Layer II Link Layer
6,7
L2 Switching
8,9 IP
Layer III Network Layer 10
Final Project

4. The Open System Interconnection Reference Model (OSI)
The OSI Reference Model is an abstract description for layered communications and computer network protocol design.
A layer is a collection of conceptually similar functions that provide services to the layer above it and receives service from the layer below it

5. The Open System Interconnection Reference Model (OSI)
Computer Networks II
Application 1 2 3 4 5 6 7
Presentation
Session
Transport
Network
Computer Networks I
Data Link
Physical

6. The Physical Layer The First Layer in the OSI Model
The Layer that actually transmits & receives data.
It defines the:
Mechanical interfaces
Electrical properties
Timing

7. Terminology Tx – Transmit Port Rx – Receive Port Loop Back Station A
Station B Tx Rx Rx Tx

8. Synchronous communication
Sender wants to transmit 01101
Sender & receiver must agree the mechanical interface between them. (cable/wireless)
Sender & receiver must agree on electrical properties for example:
5 Volt – Logical 1
0 Volt – Logical 0
Station A
Station B Tx Rx Rx Tx

9. Synchronous communication
Sender wants to transmit 01101
Transmitter side
Receiver side
Time
Voltage
Data
5 Volt
5 Volt
5 Volt
0 Volt
0 Volt 1 1
Trial 1
Received Seq: 0101 1
Trial 2
Received Seq: ? 1 5
Trial 3
Received Seq: 0?1?05
Synchronization Problem

10. Synchronous communication
Sender wants to transmit 01101
Receiver side
Transmitter side
Time
Voltage
Data 1 1 1
5 Volt
5 Volt
5 Volt
0 Volt
0 Volt
Time
Clock
Clock High
5 V
Clock Low
0 V
Received Seq: 01101

11. Synchronous communication
Communication that requires a clock signal for synchronization.
Station A
Station B
Tx 0 (Data)
Rx 0 (Data)
Tx 1 (Clk)
Rx 1 (Clk)

12. The PHY Library
The PHY is a hardware component that is responsible for the actual communication.
We will use the PHY Library to control the PHY.
Download the template project from the course homepage, this template includes the PHY library that we will be using.
PHY A Tx
PHY A Rx
PHY B Tx
PHY B Rx
MPC8360

13. The PHY Library First, you must initialize the PHY using
InitPHY();
To set the line voltage:
SetVoltage( ChannelA, ChannelB); -7 ≤ ChannelA, ChannelB ≥ 8 Example: SetVoltage( -3,4); will set voltage on channel A to be -3 volts & on channel B 4 volts You always set both channel voltages !!

14. The PHY Library To read the channel’s current voltage:
Int GetVotalge(Channel); Channel=0 for channel A Channel=1 for channel B Example: To read channel A Voltage: int ReadA=GetVotalge(0); To read channel A Voltage: int ReadB=GetVotalge(1);
To set the PHY in internal loopback mode:
SetPHYInternalLoopBackMode(1); To return to normal mode SetPHYInternalLoopBackMode(0);

15. Quick Overview