Practical Hands-on Data Communications, Networking and TCP/IP Troubleshooting for Engineers and Technicians

Transcription

1 Presents Practical Hands-on Data Communications, Networking and TCP/IP Troubleshooting for Engineers and Technicians Revision 1 Website: idc@idc-online.com

2 IDC Technologies Pty Ltd PO Box 1093, West Perth, Western Australia 6872 Offices in Australia, New Zealand, Singapore, United Kingdom, Ireland, Malaysia, Poland, United States of America, Canada, South Africa and India Copyright IDC Technologies All rights reserved. First published 2010 ISBN: All rights to this publication, associated software and workshop are reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwise without the prior written permission of the publisher. All enquiries should be made to the publisher at the address above. Disclaimer Whilst all reasonable care has been taken to ensure that the descriptions, opinions, programs, listings, software and diagrams are accurate and workable, IDC Technologies do not accept any legal responsibility or liability to any person, organization or other entity for any direct loss, consequential loss or damage, however caused, that may be suffered as a result of the use of this publication or the associated workshop and software. In case of any uncertainty, we recommend that you contact IDC Technologies for clarification or assistance. Trademarks All logos and trademarks belong to, and are copyrighted to, their companies respectively. Acknowledgements IDC Technologies expresses its sincere thanks to all those engineers and technicians on our training workshops who freely made available their expertise in preparing this manual.

3 Contents 1 Serial Data Communication Asynchronous Serial Communication Basics RS-232 Basics RS 485/422 Basics Summary 20 2 Ethernet and TCP/IP Networking Ethernet TCP/IP Protocol Suite Internet Layer (OSI Layer 3) Protocols: IP, ARP, ICMP Host-to-Host Layer (OSI Layer 4) Protocols TCP, UDP Application Layer (OSI Layer 5/6/7) Protocols: FTP, HTTP, Telnet TCP/IP Utilities Network Components Summary 93 3 Industrial Protocols: Modbus Modbus Serial Modbus TCP Summary Wireless LANs Introduction Architecture Specification Medium Access Control Frame Structure Industrial WLAN (IWLAN) Summary Security Introduction Basic Security x Authentication Differences between WPA and WPA Summary 144 Appendix A Practical Exercises (Chapter 1) 145 Appendix B Practical Exercises (Chapter 2) 167 Appendix C Practical Exercises (Chapter 2) 173 Appendix D Practical Exercises (Chapter 2) 177

4 Appendix E Practical Exercises (Chapter 2) 179 Appendix F Practical Exercises (Chapter 2) 181 Appendix G Practical Exercises (Chapter 2) 187 Appendix H Solutions (Chapter 2) 197 Appendix I Solutions (Chapter 2) 205 Appendix J Practical Exercises (Chapter 3) 207 Appendix K Practical Exercises (Chapter 4) 227 Appendix L Practical Exercises (Chapter 5) 245

5 1 Serial Data Communication Objectives When you have completed studying this chapter, you will be able to: Explain the basics of serial communication Describe the specifications of RS-232 standard and its limitations. Describe the RS-422 interface standard Describe the specifications of RS-485 interface standard. 1.1 Asynchronous Serial Communication Basics In serial communication data is sent and received one bit at a time, sequentially, over a communication channel. Most computers are typically equipped with serial ports (9 pin and 25 pin). Serial ports are used to communicate with terminals and peripheral devices. This port is also known as COM port (Communication Port). COM ports are controlled by UART (Universal Asynchronous Receiver Transmitter). Nearly all industrial and commercial communication between devices is serial, including high speed systems using USB or Local Area Networks such as Ethernet. In parallel communication, 8 (or 16 or 32) bits are sent and received simultaneously over a bus comprising 8 (or 16 or 32) channels, one for each bit. This allows data to be transferred 8 (or 16 or 32) times faster than serial communication. But in a serial link, data transfer is done using a single channel over very long distances compared to a parallel link. Parallel communication is usually only used within a device, and is beyond the scope of this course Types of Connectors Serial ports come in two sizes, 9 pin and 25 pin (Male and Female) connectors. These are known as D-Type plugs. Figure 1.1 shows the types of D-type plugs. Each pin of a serial port has specific function, hence different applications use different pins depending on the function required.

6 2 Hands-On Data Communication, Networking and TCP/IP Troubleshooting Figure 1.1 Types of connectors Pins Description Table 1.1 Pin description of 25 & 9 pin D-Type plug Function Pin Symbol 9 pin no. 25 pin no. Receive Data (Serial data input) RD 2 3 Transmit Data (Serial data output) TD 3 2 Request to send (acknowledge to modem that UART is ready to exchange data Clear to send (Modem is ready to exchange data) Data ready state (UART establishes a link) RTS 7 4 CTR 8 5 DSR 6 6 Signal ground SG 5 7 Data Carrier detect (This line is active when modem detects a carrier) DCD DTE & DCE Data Terminal Ready DTR 4 20 Ring Indicator (Becomes active when modem detects ringing signal from PSTN RI 9 22 Devices that use serial cables for their communication are split into two categories: DTE (Data Terminal Equipment) - for example, computers, printers and terminals are DTE DCE (Data Communication Equipment) - for example, modems.