Fundamentals of Data Communication Networks (eBook)

Oliver C. Ibe (Autor)

eBook Download: EPUB

2017
John Wiley & Sons (Verlag)
9781119436270 (ISBN)

Infos

What every electrical engineering student and technical professional needs to know about data exchange across networks

While most electrical engineering students learn how the individual components that make up data communication technologies work, they rarely learn how the parts work together in complete data communication networks. In part, this is due to the fact that until now there have been no texts on data communication networking written for undergraduate electrical engineering students. Based on the author's years of classroom experience, Fundamentals of Data Communication Networks fills that gap in the pedagogical literature, providing readers with a much-needed overview of all relevant aspects of data communication networking, addressed from the perspective of the various technologies involved.

The demand for information exchange in networks continues to grow at a staggering rate, and that demand will continue to mount exponentially as the number of interconnected IoT-enabled devices grows to an expected twenty-six billion by the year 2020. Never has it been more urgent for engineering students to understand the fundamental science and technology behind data communication, and this book, the first of its kind, gives them that understanding. To achieve this goal, the book:

• Combines signal theory, data protocols, and wireless networking concepts into one text
• Explores the full range of issues that affect common processes such as media downloads and online games
• Addresses services for the network layer, the transport layer, and the application layer
• Investigates multiple access schemes and local area networks with coverage of services for the physical layer and the data link layer
• Describes mobile communication networks and critical issues in network security
• Includes problem sets in each chapter to test and fine-tune readers' understanding

Fundamentals of Data Communication Networks is a must-read for advanced undergraduates and graduate students in electrical and computer engineering. It is also a valuable working resource for researchers, electrical engineers, and technical professionals.

OLIVER C. IBE, ScD, is a Professor of Electrical Engineering and the Associate Dean of Engineering for Undergraduate Studies at the University of Massachusetts, Lowell, Massachusetts, USA. He has sixteen years of experience in the telecommunication industry including stints as Chief Technology Officer and cofounder of Sineria Networks, and the Director of Network Architecture at both Spike Broadband Systems and Adaptive Broadband Corporation. Dr. Ibe has published numerous books on the subjects of telecommunication technologies and applied probability.

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Chapter 1
Overview of Data Communication Networks

1.1 Introduction

In a very broad sense, a network is any interconnected group of people or devices that are capable of sharing meaningful information with one another. In the telecommunication sense, a data communication network is a collection of two or more computing devices that are interconnected to enable them to share data. Data communication networking arose in response to the need to share data in a timely manner. Data sharing and information dissemination are critical to the success of any business. Thus, data communication networks are important to all contemporary organizations.

As discussed earlier, data communication networks deal with the transfer of data between two points. Data originates at the source and is finally delivered to the destination, which is also called a sink. Sometimes, the source and destination are interconnected by one link; at other times, the data must traverse multiple links to reach the destination. A typical communication environment includes multiple sources and sinks that are interconnected by communication links to build a network. Thus, a communication network is essentially an arrangement of hardware and software that allows users to exchange information.

1.2 Data Communication Network Model

A communication model is necessary to enable us to introduce the main elements of a communication system as well as to define some of the terminology used in the remainder of this book. A communication system consists of the following:

• A source that generates the information.
• A source encoder that converts the information into an electrical form called message signal m(t).
• A transmitter that is used to convert the message signal into a form acceptable to the channel.
• The channel is the path or link that connects the transmitter and the receiver; it can be metallic, optical fiber, or air.
• A receiver performs an inverse function of that of the transmitter to recover the message signal.
• A source decoder converts the electrical signal back to a form acceptable to the receiver.
• A sink is the user of the information generated by the source.

The model is illustrated in Figure 1.1.

Figure 1.1 A Data Communication Network Model.

Note that information flow can be bidirectional because what is a source at one time can be a sink at another time. Thus, Figure 1.1 shows the basic blocks used to process information as it flows in one direction.

The simplest data communication network consists of a source that is directly connected to a sink, as shown in Figure 1.2.

Figure 1.2 A Simple Data Communication Network.

In a more complex network, the two communicating nodes are interconnected by a complex structure, which is usually represented by a cloud as shown in Figure 1.3.

Figure 1.3 Representation of a Complex Network Structure.

1.3 Classification of Data Communication Networks

There are different ways to classify a data communication network, which are as follows:

• Transmission method
• Data flow direction
• Network topology
• Geographical coverage
• Transmission medium
• Data transfer technique
• Network access technique
• Media sharing technique.

In this section, we describe each of these methods.

1.3.1 Transmission Method

Data transmission method can be classified in two fundamental ways: asynchronous and synchronous transmissions. Asynchronous transmission is used when data is transmitted as individual characters. In this method, each character is preceded by one start bit and one or two stop bits that are used by the receiver for synchronization purposes. The need for synchronization arises from the fact that the interval between characters is random, which means the receiver that has been idle for some time needs to know when data is coming in.

Synchronous transmission is used to transmit large blocks of data at a time. In this scheme, data is usually organized in frames and each frame is preceded by a flag that consists of a few bits, and terminated by another flag. It is more efficient than asynchronous transmission because the overhead is smaller on a character-by-character basis. Figure 1.4 illustrates the difference between an asynchronous transmission scheme and a synchronous transmission scheme.

Figure 1.4 Asynchronous versus Synchronous Transmission. (a) Character-oriented asynchronous transmission and (b) frame-oriented synchronous transmission.

1.3.2 Data Flow Direction

Three ways are used to characterize the direction of data flow: simplex, half duplex, and full duplex. In a simplex transmission, data can only flow in one direction, which is usually from the source to the sink. This is illustrated in Figure 1.5.

Figure 1.5 Simplex Transmission.

In a half-duplex transmission (HDX) data can flow in both directions, but never simultaneously. It first flows in one direction, and then in the other direction. Thus, one station is the source and the other is the sink. Then the roles are interchanged such that the previous source becomes the sink and the previous sink becomes the source, and so on. This is illustrated in Figure 1.6.

Figure 1.6 Half- Duplex Transmission.

In a full-duplex transmission (FDX), data can flow in both directions simultaneously. It can be viewed as a pair of simplex lines between the source and sink with one line going from the source to the sink and the other going from the sink to the source. This is illustrated in Figure 1.7.

Figure 1.7 Full- Duplex Transmission.

1.3.3 Network Topology

Network topology refers to the different geometrical configurations that can be used to build a network. Different topologies exist and include the following:

• Point-to-point (P2P)
• Point-to-multipoint
• Multidrop
• Bus
• Ring (or loop)
• Star
• Tree
• Mesh.

In the P2P topology, a link permanently connects two nodes or network devices. The P2P topology is illustrated in Figure 1.8. Note that the link interconnecting two nodes can be either a wireless (or air) or a wired connection.

Figure 1.8 Point-to-Point Topology.

In the point-to-multipoint topology, one node is connected to multiple nodes, each in a P2P manner, as illustrated in Figure 1.9.

Figure 1.9 Point-to-Multipoint Topology.

In the multidrop topology, all nodes are interconnected by a single link with one node that is the master node and the other nodes are secondary or slave nodes. The master node usually controls access to the link and is located at one end of the link as illustrated in Figure 1.10.

Figure 1.10 Mulitdrop Topology.

The bus topology is similar to the multidrop topology with the exception that there is no master–slave relationship; all nodes are peers. The topology is illustrated in Figure 1.11.

Figure 1.11 Bus Topology.

The line terminator in the figure is used to prevent a signal that comes to the end of a transmission line from bouncing back and corrupting other signals on the line. This “bouncing back” is called signal reflection and it has the tendency to interfere with and, therefore, corrupt the data on the line.

In ring topology, the nodes are connected serially in a P2P manner with the last node connected to the first node to form a loop. This is illustrated in Figure 1.12.

Figure 1.12 Ring Topology.

A star topology is a topology in which each node is connected in a P2P manner to a central node, called a hub. This is illustrated in Figure 1.13. Note that the star topology is similar to the point-to-multipoint topology. The difference between the two is that in the star topology, the hub is a passive device that does not control access to the network, while in the point-to-multipoint topology, the central node is an active device that controls communication in the network.

Figure 1.13 Star Topology.

A tree topology is formed by connecting multiple buses together to form a system of branching links with no closed loop. It has a special node called the headend from which information flows to the other nodes. The topology is illustrated in Figure 1.14.

Figure 1.14 Tree Topology.

In the mesh topology, the network nodes are interconnected in an arbitrary manner. Generally, users are connected to only a subset of the nodes and another set of internal nodes provides a switching facility that moves data from one node to another until it reaches its destination. An example of the mesh topology is shown in Figure 1.15.

Figure 1.15 Mesh Topology.

1.3.4 Geographical Coverage

Networks are sometimes classified according to their geographical coverage....

Produkt-Details

• Erscheint lt. Verlag: 20.12.2017
• Sprache: englisch
• Themenwelt: Naturwissenschaften
• Themenwelt: Sozialwissenschaften ► Kommunikation / Medien ► Kommunikationswissenschaft
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Themenwelt: Technik ► Nachrichtentechnik
• Schlagworte: classification of data communication networks • communication network engineering • communication network principles • communication network theory • Communication technology • Communication Technology - Networks • data communication • data communication fundamentals • data communication networks for electrical engineers • data communication networks overview • data exchange on networks • data link protocols for data networks • data network architecture • data networking protocols • data network physical layer • data network technologies • digital modulation schemes for data networks • Drahtlose Kommunikation • Electrical & Electronics Engineering • Elektrotechnik u. Elektronik • fourier analysis for data networks • fourier transforms for signal processing • fundamentals of data communication networks for electrical engineers • Kommunikationsnetze • Kommunikationstechnik • local area network technologies • Mobile & Wireless Communications • multiple access schemes for data networks • network ip address principles • Telecommunication Protocols • variable length subnet mask networks • virtual lans • wireless networking basics for engineers
• ISBN-13: 9781119436270 / 9781119436270