JABATAN KEJURUTERAAN ELEKTRIK POLITEKNIK SEBERANG PERAI data communication & networking masliza binti maskin wan marlina binti wan ahmad dep 50033
©All rights reserved for electronic, mechanical, recording, or otherwise, without Politeknik Seberang Perai's prior written permission. MASLIZA BT MASKIN WAN MARLINA BT WAN AHMAD 2023 JABATAN KEJURUTERAAN ELEKTRIK
All Right Reserved Tel : 04-538 3322 Fax: 04-538 9266 Email: webmaster@psp.edu.my Website: www.psp.edu.my FB : politeknikseberangperai IG : politeknikseberangperai Editor Masliza Maskin Wan Marlina Wan Ahmad Content Reviewer Norfazilah Binti Ja’afar Cover Designer Ts. Azilah bt Abd Rahim Politeknik Seberang Perai Jalan Permatang Pauh, 13500 Permatang Pauh Pulau Pinang No part of this publication may be translated or reproduced in any retrieval system, or transmitted in any form or by any means, electronic, mechanical, recording, or otherwise, without prior permission in writing from Politeknik Seberang Perai. Masliza Maskin, editor. Wan Marlina Wan Ahmad, editor. DATA COMMUNICATION & NETWORKING : DEP 50033 / Editor Masliza Maskin, Wan Marlina Wan Ahmad 2023 Politeknik Seberang Perai, Electronic books -- Data transmission systems Digital communications -- Computer networks -- Government publications -- Malaysia e ISBN 978-967-2774-37-2
Table of Contents Acknowledgement....................................................................4 Preface..............................................................................................5 Chapter 1..........................................................................................6 Chapter 2.......................................................................................38 Chapter 3.......................................................................................64 Chapter 4.......................................................................................75 Chapter 5.....................................................................................105
riting this ebook, "Data Communication & Networking," has been a journey of exploration and learning, made possible through the support, guidance, and contributions of numerous individuals and resources. We would like to express our sincere gratitude to all those who have contributed to the creation and development of this ebook, "Data Communication & Networking." Furthermore, We would like to thank our family and friends for their unwavering encouragement and understanding during the time dedicated to researching and writing this ebook. Your support has been the cornerstone of my efforts. This ebook would not have been possible without the collective efforts and support of all these individuals and the countless others who have contributed in various ways.. Thank you for being an integral part of this journey. Warm regards, MASLIZA BINTI MASKIN WAN MARLINA BINTI WAN AHMAD ELECTRICAL ENGINEERING DEPARTMENT POLITEKNIK SEBERANG PERAI Acknowledgement W
Welcome to "Data Communication & Networking." In this ebook, we embark on a journey through the realm of digital connectivity that shapes our modern world. As technology advances, the ability to communicate and share data instantaneously has become a cornerstone of our lives. This ebook serves as an introduction to the principles and concepts that drive data communication and networking systems. Whether you're a student aiming to grasp the basics or an enthusiast eager to understand the mechanics behind the websites you visit and the messages you send, this ebook provides a foundation for exploring this dynamic field. We'll explore topics ranging from the basics of data transmission to the intricacies of network protocols and security measures. Real-world examples and straightforward explanations aim to make the content accessible to all readers. We hope this ebook sparks your curiosity and provides insights into the invisible yet powerful systems that enable our interconnected world. Let's dive in and uncover the mysteries of data communication and networking. Best regards, Masliza Maskin, Wan Marlina Wan Ahmad 31 August 2023 Preface
01 BASIC CONCEPT OF DATA COMMUNICATION
01 BASIC CONCEPT OF DATA COMMUNICATION CONTENTS 1.1 Remember basic data communication system 1.2 Understand data encoding 1.3 Evaluate digital-to-digital encoding 1.4 Understand Digital Modulation 1.5 Apply digital modulation 1.6 Evaluate error detectionin data transmission 1.7 Evaluate the quality of data transmission
Define Data Communication Basic Communication Model Source Sink (Destination) Block Diagram Basic Communication Exchangeable of digital data coding between two devices via some form of transmission medium. Telecommunication Network Terminal Modem Terminal Modem The system consists of group up the data, processing the data and transmit the data using a specified communication channel Data Communication 01 BASIC CONCEPT OF DATA 01 COMMUNICATION Remember Basic Data Communication System 1.1 Channel DTE DCE DCE DTE
01 Data Communication Equipment(DCE) Data Terminal Equipment (DTE) Describe A subscriber equipment or user’s device for data communications. Consists of a source of data or receiving data or both. These tools may include an error control, synchronization and identification capabilities of the station. Examples of DTE is the computers, logical control, visual display units and work station. DCE is capable of implementing, operating and terminate a data communication, exchanging signals and coding needed to make the relationship between the DTE and data circuits. Internal or external parts of a computer. Example: a modem or data set. Provided by authorities or by client communication network itself. BASIC CONCEPT OF DATA COMMUNICATION
Amplitude Shift Keying (ASK) Frequency Shift Keying (FSK) Phase Shift Keying (PSK) Digital-toAnalog encoding Analog-to- Pulse Code Modulation (PCM) Digital encoding Understand Data Encoding 1.2 01 BASIC CONCEPT OF DATA COMMUNICATION 1.2.1 Types of Data Encoding
Understand Data Encoding 1.2 01 BASIC CONCEPT OF DATA COMMUNICATION 1.2.1 Types of Data Encoding Analog-toAnalog encoding Digitalto-Digital encoding Unipolar Non-Return-to-Zero (NRZ) encoding Unipolar Return-to-Zero (RZ) encoding High Density Bipolar 3-zero (HDB3) Multiline Transmission-3 Level (MLT-3) Block coding: 4B/5B Manchester Encoding Alternate Mark Inversion (AMI) Amplitude Modulation (AM) Frequency Modulatio (FM) Phase Modulation(PM)
Understand Data Encoding Traditionally, a unipolar scheme was design as a NRZ: A. UNIPOLAR NON RETURN TO ZERO (NRZ) 0 = Low voltage level (0V) 1 = High voltage level (+V volts) Non Return to Zero Level (NRZ-L) Non Return to Zero Invert (NRZ-I) 0 = High voltage level (+V volts) 1 = Low voltage level (-V volts) next bit is 0 = No changes voltage level next bit is 1 = Changes voltage level The main problem with NRZ encoding occurs when the sender and receiver clocks are not synchronized. The receiver does not know when one bit has ended and the next bit is starting. One solution is return-to-zero (RZ) scheme. 01 1.2 BASIC CONCEPT OF DATA COMMUNICATION Explain the digital-to-digital data encoding with an illustration Figure 1-1 Unipolar Non Return to Zero Figure 1-2 NRL-Z and NRZ-I
01 BASIC CONCEPT OF DATA COMMUNICATION Explain the digital-to-digital data encoding with an illustration RZ uses three value: positive, negative and zero. The signal changes not between bits but during the bit. Bit 0 = Transition from low to high in the middle of a bit (-ve in 1st half and 0 in 2nd half). Bit 1= Transition from high to low in the middle of a bit (+ve in 1st half and 0 in 2nd half). B. UNIPOLAR RETURN TO ZERO (RZ) The problem of RZ are: That it requires two signal changes to encode a bit. A sudden change of polarity resulting in all 0s interpreted as 1s and all 1s interpreted as 0s but no DC component problem. Use three level of voltage which is more complex to create and discern. RZ has been replaced by better performing Manchester and Differential Manchester schemes.
C. MANCHESTER CODE Also known as Bi-phase Encoding. The duration of the bit is divided into two halves. The voltage remains at one level during the first half and moves to the other level during the second half. Bit 0 = Transition from high to low in the middle of a bit (+ve in 1st half and -ve in 2nd half). Bit 1= Transition from low to high in the middle of a bit (-ve in 1st half and +ve in 2nd half). Another types of Manchester code is Differential Manchester. 01 BASIC CONCEPT OF DATA COMMUNICATION Explain the digital-to-digital data encoding with an illustration Next bit is 0 = Inversion Next bit is 1 = No Inversion Figure 1-3 Types of Manchester Code
0 = Neural zero (0 volts) 1 = Alternate Positive (+) and Negative (-) voltages for successive 1’s This code is used in long distance. This code reduces/ no the DC(Direct Current) content from the line; the 1’s will have positive voltage followed by negative voltage, in other words, the voltages go up and down. This code has a problem. A long stream of 0’s can cause a receiver to go out of synchronization (lose the bit boundaries) since 0’s have no voltage. D. BIPOLAR AMI (ALTERNATE MARK INVERSION) 01 BASIC CONCEPT OF DATA COMMUNICATION Explain the digital-to-digital data encoding with an illustration Figure 1-4 Bipolar AMI Figure 1-5 Diagram of Bipolar AMI
The HDB3 code is a bipolar signaling technique (i.e. relies on the transmission of both positive and negative pulses). It is based on Alternate Mark Inversion (AMI), but extends this by inserting violation codes whenever there is a run of 4 or more 0's. This and similar (more complex) codes have replaced AMI in modern distribution networks. Four consecutive zero-level voltages are replaced with a sequence of 000V or B00V. The reason for two different substitutions is to maintain the even number of nonzero pulses after each substitution. E. HIGH DENSITY BIPOLAR ORDER 3 ENCODING (HDB3) 01 BASIC CONCEPT OF DATA COMMUNICATION Explain the digital-to-digital data encoding with an illustration Figure 1-6 Diagram of High Density Bipolar Order 3 Encoding (HDB3)
These rules are applied on the code as it is being built from the original string. Every time there are 4 consecutive zeros in the code they will be replaced by either 000−, 000+ , +00+ or −00−. To determine which pattern to use, one must count the number of pulses (+) and the number of minuses (−) since the last violation bit V, then subtract one from the other. If the result is an odd number then 000− or 000+ is used. If the result is an even number then +00+ or −00− is used. To determine which polarity to use, one must look at the pulse preceding the four zeros. If 000V form must be used then V simply copies the polarity of last pulse, if B00V form must be used then B and V chosen will have the opposite polarity of the last pulse. E. HIGH DENSITY BIPOLAR ORDER 3 ENCODING (HDB3) CONT... 01 BASIC CONCEPT OF DATA COMMUNICATION Explain the digital-to-digital data encoding with an illustration Figure 1-7 Encoding of Substitution Code Figure 1-8 Diagram of Substitution Code
01 BASIC CONCEPT OF DATA COMMUNICATION Explain the digital-to-digital data encoding with an illustration E. HIGH DENSITY BIPOLAR ORDER 3 ENCODING (HDB3) CONT... If B00V; B and V chosen will have the opposite polarity of the last pulse. If 000V; V simply copies the polarity of last pulse, Figure 1-9 Examples of Substitution Code Figure 1-10 Diagram of Substitution Code
MLT-3 encoding is a line code that uses three voltage levels. MLT-3 cycles sequentially through the voltage levels +V, 0, - V, 0,…. +V, 0, -V, 0. It moves to the next state to transmit a 1 bit, and stays in the same state to transmit a 0 bit. Similar to simple NRZ encoding, MLT-3 has a coding efficiency of 1 bit/baud, however it requires four transitions (baud) to complete a full cycle. Thus, the maximum fundamental frequency is reduced to one fourth of the baud rate. This makes signal transmission more amenable to copper wires. 01 BASIC CONCEPT OF DATA COMMUNICATION Explain the digital-to-digital data encoding with an illustration F. MLT-3 ENCODING (MULTI-LEVEL TRANSMIT) Figure 1-11 Diagram of MLT-3 encoding (Multi-Level Transmit)
G. 4B/5B ENCODING 4B/5B refers to the fact that every nibble of 4 Bits of data is encoded into 5 Bits of signal. Specified by the American National Standards Institute (ANSI) X3T9.5 committee recommendation for FDDI, 4B/5B is sometimes referred to as block coding, as a block of data bits is mapped into a block of signaling bits. This approach increases the number of bit patterns from 16 (2 4 = 16) to 32 (2 5 = 32), which means that each five-bit signal block includes enough clocking pulses and signal transitions to synchronize the network. 4B5B also provides some level of error detection. So, the signaling rate must be 125 MHz to support a unipolar code (such as that used with classic 10 Mbps Ethernet) with a signaling rate of 125 Mbps, which, in turn, supports a data rate of 100 Mbps. 01 BASIC CONCEPT OF DATA COMMUNICATION Explain the digital-to-digital data encoding with an illustration Figure 1-12 Diagram of 4B/5B Encoding Figure 1-13 Table of 4B/5B Encoding
Understand Digital Modulation Information Signal is in digital waveform. While Carrier signal is in analog waveform. There are four basic technique for digital modulation . Digital - to - Analog Conversion Amplitude Shift Keying (ASK) Frequency Shift Keying (FSK) Phase Shift Keying (PSK) Quadrature Amplitude Modulation (QAM) 01 1.4 BASIC CONCEPT OF DATA COMMUNICATION Figure 1-14 Frameworks of Digital Modulation
01 BASIC CONCEPT OF DATA COMMUNICATION Amplitude Shift Keying (ASK) ASK is a process where the binary information signal directly modulates the amplitude of an analog carrier. The carrier is transmitted when the modulating data is ‘one’ and the carrier is rejected from transmission when the data is ‘zero’. When the data is bit ‘1’, the carrier signal has the amplitude, when the data is bit ‘0’, the amplitude of carrier signal is 0. Figure 1-15 Diagram of Amplitude Shift Key
In FSK, the frequency of the carrier signal is varied to represent data. Amplitude and phase of the carrier signal remain the same. As the binary input signal changes from a logic 0 to a logic 1 and vice versa, the output frequency shifts between two frequencies: a mark, or logic 1 frequency (fm) and a space, or logic 0 frequency (fs). 01 BASIC CONCEPT OF DATA COMMUNICATION Frequency Shift Keying (FSK) Figure 1-16 Diagram of Frequency Shift Key
The phase of the carrier is varied to represent two or more different signal elements. Both peak amplitude and frequency remain constant. The input is a binary digital signal and there are a limited number of output phase possible. The input binary information is encoded into groups of bits before modulating the carrier. The simplest form of PSK is binary shift keying (BPSK), which have only 2 signal elements ; (phase of 0° & phase of 180°). These two phases will represent a logic ‘1’ and logic ‘0’. 01 BASIC CONCEPT OF DATA COMMUNICATION Phase Shift Keying (PSK) Figure 1-17 Diagram of Phase Shift Key
Amplitude Shift Keying (ASK) The amplitude (V) of the carrier is varied proportional to the information signal. FREQUENCY SHIFT KEYING (FSK) The frequency (f) of the carrier is varied proportional to the information signal. PHASE SHIFT KEYING (PSK) The phase (Ɵ) of the carrier is varied proportional to the information signal. QUADRATURE AMPLITUDE MODULATION (QAM) Both amplitude (V) and phase (Ɵ) are varied proportional to the information signal. 01 BASIC CONCEPT OF DATA COMMUNICATION ~DIGITAL MODULATION SUMMARY~ Figure 1-18 Diagram of Digital Modulation Summary
In binary coding: Data bit ‘1’ has waveform 1 Data bit ‘0’ has waveform 2 Data rate = bit rate = symbol rate In M-ary coding, take M bits at a time (M = 2k) and create a waveform (or symbol). ‘00’ waveform (symbol) 1 ‘01’ waveform (symbol) 2 ‘10’ waveform (symbol) 3 ‘11’ waveform (symbol) 4 Symbol rate = bit rate/k M-ary is a term derived from the word binary. M = represents a digit that corresponds to the number of conditions or levels or combinations possible for a given number of binary variables (n). For example, a digital signal with 4 possible conditions (either voltage, levels, frequencies, phases and so on) is an M-ary system where M = 4. The number of bits that necessary to produce a given number of conditions (M) is expressed mathematically as; 01 BASIC CONCEPT OF DATA COMMUNICATION M-ARY CODING Relate the concept of Multi-level (M-ary) amplitude and phase modulation with: a. Quadrature Phase Shift Keying (QPSK or 4-PSK) b. Quadrature Amplitude Modulation (QAM) Where; n = number of bits M = number of conditions, levels or combinations possible with n bits
A. Quadrature Phase Shift Keying (QPSK) ► A phase modulation technique that transmits two bits in four modulation states. 01 BASIC CONCEPT OF DATA COMMUNICATION Equation above can be simplified and rearranged to express the number of conditions possible, M with n bits. For example, with n = 1 bit, only 21 = 2 conditions are possible. With two bits, 22 = 4 conditions are possible. With three bits, 23 = 8 conditions are possible, and so on. M-ARY CODINGCont... 100 – phase 0° 10 – phase 180° 01 - phase 90 ° 11 – phase 270° Figure 1-19 Multi-level (M-ary) Modulation Figure 1-20 Quadrature Phase Shift Keying (QPSK)
01 BASIC CONCEPT OF DATA COMMUNICATION M-ARY CODING Cont... ► QPSK is a form of PSK in which two bits are modulated at once, selecting one of four possible carrier phase shifts 0,90,180,270 or 0, 45, 135, .. ► QPSK perform by changing the phase of the In-phase (I) carrier from 0° to 180° and the Quadrature-phase (Q) carrier between 90° and 270°. ► QPSK digital data is represented by 4 points of a 2-bit binary code around a circle which correspond to 4 phases of the carrier signal. These points are called symbols. B. Quadrature Phase Shift Keying (QPSK/ PSK) Figure 1-23 Constellation diagram for QPSK with Gray coding. Each adjacent symbol only differs by one bit. Figure 1-22 Constellation diagram example for BPSK. Figure 1-21 Quadrature Phase Shift Keying (QPSK) Figure 1-24 Gray Code diagram by Bit Width
01 BASIC CONCEPT OF DATA COMMUNICATION M-ARY CODING Cont... C. QUADRATURE AMPLITUDE MODULATION (QAM) QAM is a combination of ASK and PSK so that a maximum contrast between each signal unit (bit, dibit, tribit, and so on) is achieved. QAM technique that widely used to transmit digital signals such as digital cable TV and cable Internet service, QAM also used as the modulation technique in orthogonal frequency division multiplexing The "quadrature" comes from the fact that the phase modulation states are 90 degrees apart from each other. Figure 1-25 QAM and 8 -QAM constellations Figure 1-26 QAM and 8 -QAM Diagram
QPSK 16-QAM Have amplitude levels Depending on type. i.e 16-QAM,64-QAM,256- QAM. How many amplitude levels to be used accordingly i.e 16,64,256 01 BASIC CONCEPT OF DATA COMMUNICATION COMPARISON BETWEEN QAM AND QPSK QPSK QAM Using phases for representation of messages. 2 bits per symbol is used with four different phases. Figure 1-27 QAM and 8 -QAM Comparison Diagram
Minimum shift keying, MSK, is a form frequency modulation based on a system called continuous-phase frequency-shift keying. Minimum shift keying, MSK offers advantages in terms of spectral efficiency when compared to other similar modes, and it also enables power amplifiers to operate in saturation enabling them to provide high levels of efficiency. When looking at a plot of a signal using MSK modulation, it can be seen that the modulating data signal changes the frequency of the signal and there are no phase discontinuities. This arises as a result of the unique factor of MSK that the frequency difference between the logical one and logical zero states is always equal to half the data rate. Phase Continuous Frequency Changes 01 BASIC CONCEPT OF DATA COMMUNICATION MINIMUM SHIFT KEYING (MSK) Figure 1-28 Minimum Shift Keying (MSK) Diagram
01 BASIC CONCEPT OF DATA COMMUNICATION GAUSSIAN MINIMUM SHIFT KEYING The Gaussian Minimum Shift Keying (GMSK) modulation is a modified version of the Minimum Shift Keying (MSK) modulation where the phase is further filtered through a Gaussian filter to smooth the transitions from one point to the next in the constellation. GMSK is a advanced version of MSK Figure 1-29 Concept of a minimum shift keying, MSK signal Figure 1-30 GMSK spectral density with offset from carrier
Single bit errors are the least likely type of errors in serial data transmission because the noise must have a very short duration which is very rare. However this kind of errors can happen in parralel transmission. Example : If data is sent at 1Mbps then each bit lasts only 1/1,000,000 sec or 1 us. For a single bit error to occur, the noise must have a duration of only 1 us, which is very rare SINGLE BIT ERROR 01 BASIC CONCEPT OF DATA COMMUNICATION Evaluate Error Detection in Data Transmission 1.6 Errors Single - bit Multiple - bit Burst Types of Errors Figure 1-31 Example of single bit errorsr
01 BASIC CONCEPT OF DATA COMMUNICATION MULTIPLE BIT ERROR The condition when more than one bit is in error in a given number of bits. In case of burst error, if two or more bits from a data unit such as byte change from 1 to 0 or from 0 to 1 then burst errors are said to have occurred. the length of burst is measured from the first corrupted bit to last corrupted bit. BURST ERROR Burst error is most likely to happen in serial transmission since the duration of noise is normally longer than the duration of a bit. The number of bits affected depends on the data rate and duration of noise. Example: -> If data is sent at rate = 1Kbps then a noise of 1/100 sec -> If same data is sent at rate = 1Mbps then a noise of can affect 10 bits. (1/100*1000) 1/100 sec can affect 10,000 bits. (1/100*106 Figure 1-32 Example of Multiple bit error Figure 1-33 Example of Burst error
Initial value: 0101010 (three 1s) Parity bit added: 1 Transmitted value: 01010101 Result: Even parity (four 1s) 01 BASIC CONCEPT OF DATA COMMUNICATION PARITY BIT IN VERTICAL REDUNDANCY CHECK (VRC) – ALSO KNOWN AS PARITY CHECKParity Checking - Add an additional bit (parity bit) to each byte in the message. Parity bits are often used in data transmission to ensure that data is not corrupted during the transfer process. A parity bit is a bit, with a value of 0 or 1, that is added to a block of data for error detection purposes. It gives the data either an odd or even parity which is used to validate the integrity of the data. EVEN PARITY ODD PARITY Initial value: 1010100 (three 1s) Parity bit added: 0 Transmitted value: 10101000 Result: Odd parity (three 1s) EXERCISE
In CRC technique, some importance points must be used such as Data sent, M(x) and CRC generator, G(x) to check either the data have an error or not. We must find the new M(x) data by added some bits ( numbers bit of G(x) -1) or by using polynomials procedures. So, the data sent, new M(x) must be divides by CRC generator, G(x) and if there is no remainder, assumes there was no error during the transmission process. If there are the remainder we must add that remainder to the M(x) and divides with CRC generator again. To clarify this, we present the procedure in modulo 2 arithmetic and digital logic. A cyclic redundancy check (CRC) is a form of data verification used by computer software and networking protocols to ensure there has been no corruption to the data being checked. 01 BASIC CONCEPT OF DATA COMMUNICATION CYCLIC REDUNDANCY CHECK (CRC) Modulo 2 arithmetic uses binary addition with no carries, which is just the exclusive or operation. For example: --------------------->
Data received in a receiver is: Message M(x) = 1001011001100 (13 bits) CRC generator = 1011 (The numbers of CRC generator is 4 bits). By using CRC technique prove that there is no errors during the transmission. 01 BASIC CONCEPT OF DATA COMMUNICATION EXERCISES Question 1 Question 2 Question 3 Given data sent, M(x) = 1101011011 and CRC generator G(X) is 10011. For error detection, by using CRC technique determine the CRC bits that should be added to the data block M(x) during the transmission. Prove there is no error happens at receiver part. Given data sent, M(x) = 1100011011 and CRC generator G(X) is 100110. For error detection, by using CRC technique determine the CRC bits that should be added to the data block M(x) during the transmission. Prove there is no error happens at receiver part.
02 INTRODUCTION TO NETWORKING
02 INTRODUCTION TO NETWORKING CONTENTS 2.1 Remember basic concept and elements of computer network 2.2 Apply the fundamental types of networks 2.3 Understand network classification 2.4 Evaluate the wiring standard in network cabling preparation 2.5 Evaluate networking cabling 2.6 Understand network security
WHAT IS COMPUTER NETWORK WHY USE NETWORK? Sharing Information A combination of computer hardware, cabling, network devices, and computer software used together to allow computers to communicate with each other. Group of computers and other devices that are connected by some type of transmission media 02 E.g. Internet-based, so everyone can access the same administrative or support application from their PCs Sharing hardware and software Centralize administration and support INTRODUCTION TO NETWORKING Remember Basic Concept & Elements of Computer Network 2.1
The advantages of networked computing relative to standalone computing Fewer Peripherals Needed: many devices can be connected on a network Increased Communication Capabilities: network provide several different collaboration tools that can be used to communicate between network users. 1 2 3 4 5 Avoid File Duplication and Corruption: a server manages network resources. Server store data and share it with users on a network Lower Cost Licensing: application licensing can be expensive for individual computers Centralized Administration: centralized processing can be distributed across many computers to prevent one computer from becoming overloaded with processing tasks. 02 INTRODUCTION TO NETWORKING
02 INTRODUCTION TO NETWORKING Fundamental Types of Networks Figure 2-1 Resource sharing on a simple peer-to-peer network Figure 2-2 Resource sharing on a client/server network Networking Standards Networking standards define the rules for data communications that are needed for interoperability of networking technologies and processes.
02 INTRODUCTION TO NETWORKING The Advantages & Disadvantages of Peer to Peer Networking Figure 2-3 The Advantages & Disadvantages of Peer to Peer Networking
Maintenance – Large networks will require a staff to ensure efficient operation High cost for Servers 02 INTRODUCTION TO NETWORKING The Advantages & Disadvantages of client/server Networking Need expert to configure the network Disadvantages of client/server Networking Advantages of client/server Networking Centralized – resources and data security are controlled through the server Scalability – any or all elements can be replaced individually as needs increase Flexibility – new technology can be easily integrated into system Interoperability – all components (Client/network/server) work together Accessibility - server can ne accessed remotely and across multiple platforms
02 INTRODUCTION TO NETWORKING Common Elements to Client/Server Networks Network computer requesting resources or services from another network computer Client workstation human user Client software installed on workstation Network computer managing shared resources Runs network operating system that manage not only data, but also users, groups, security and applications on the network Personal computer May or may not be connected to network Network Interface Card Device inside computer Connects computer to network media Allows communication with other computers Network operating system Server software Enables server to manage data, users, groups, security, applications, and other networking functions A computer that enables other computers to share resources Client Server Workstation NIC NOS Host
Group of nodes A part of a network Use same communications channel for traffic 02 INTRODUCTION TO NETWORKING Common Elements to Client/Server Networks Connects segments and significant shared devices “A network of networks” Computer network physical layout Ring, bus, star or hybrid formation Allows multiple networks or multiple parts of one network to connect and exchange data Such as a switch or router Client, server, or other device Communicates over a network Identified by unique number (network address) Node Connectivity Device Segment Backbone Topology
Networking Hardware 02 INTRODUCTION TO NETWORKING Construct the Networks Apply The Fundamental Types of Network 2.2 Network hardware is defined as a set of physical or network devices that are essential for interaction and communication between hardware units operational on a computer network.
Switches no longer broadcast network packets as hubs did in the past, they memorize addressing of computers and send the information to the correct location directly Switches add more intelligence to data transfer management. 02 INTRODUCTION TO NETWORKING HUB A concentrator is a device that provides a central connection point for cables from workstations, servers, and peripherals. In a star topology, twisted-pair wire is run from each workstation to a central switch/hub. Most switches are active, that is they electrically amplify the signal as it moves from one device to another Networking Hardware SWITCH BRIDGES A bridge is a device that allows you to segment a large network into two smaller, more efficient networks. If you are adding to an older wiring scheme and want the new network to be up-to-date, a bridge can connect the two. A bridge monitors the information traffic on both sides of the network so that it can pass packets of information to the correct location. Figure 2-4 Bridges
A gateway is a device used to connect networks using different protocols. Gateways operate at the network layer of the OSI model. In order to communicate with a host on another network, an IP host must be configured with a route to the destination network. Gateways receive data from a network using one type of protocol stack, removes that protocol stack and repackages it with the protocol stack that the other network can use. Networking Hardware 02 INTRODUCTION TO NETWORKING Routers are used to connect networks together Route packets of data from one network to another Cisco became the de facto standard of routers because of their highquality router products Routers, by default, break up a broadcast domain ROUTERS GATEWAY Since a signal loses strength as it passes along a cable, it is often The repeater electrically amplifies the signal it receives and rebroadcasts it. Repeaters can be separate devices or they can be incorporated into a concentrator necessary to boost the signal with a device called a repeater. REPEATER