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Cody Singh
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Prakash C. Gupta's Data Communications And Computer Networks: An In-depth Analysis with Examples and Exercises


Data Communication And Computer Networks Prakash C Gupta Pdf 157l




Data communication and computer networks are two interrelated fields that deal with the exchange and processing of information using electronic devices and systems. They are essential for modern society, as they enable various applications and services such as e-commerce, e-learning, e-government, social media, cloud computing, Internet of Things, etc. In this article, we will explore the main topics covered in the book "Data Communications And Computer Networks" by Prakash C Gupta, which is a comprehensive and up-to-date text that gives an in-depth analysis of data communication and computer networks in an easy-to-read style. The book provides standard protocols, thereby enabling to bridge the gap between theory and practice. It also correlates the network protocols to the concepts, which are explained with the help of numerous examples to facilitate students' understanding of the subject. The book is divided into 18 chapters, each covering a different aspect of data communication and computer networks. We will summarize the key points and findings of each chapter in the following sections.




Data Communication And Computer Networks Prakash C Gupta Pdf 157l



Transmission Media




Transmission media are the physical means through which data signals are transmitted from one point to another in a network. They can be classified into two types: guided media and unguided media. Guided media are those that provide a physical path for data signals, such as twisted pair cables, coaxial cables, and optical fibers. Unguided media are those that do not provide a physical path for data signals, but rather use electromagnetic waves to propagate them through space, such as radio waves, microwaves, and infrared waves. The choice of transmission media depends on several factors, such as bandwidth, attenuation, noise, cost, availability, etc. Each type of transmission media has its own advantages and disadvantages. For example, twisted pair cables are cheap and easy to install, but have low bandwidth and high attenuation. Optical fibers have high bandwidth and low attenuation, but are expensive and difficult to install. Radio waves can cover long distances and penetrate obstacles, but are susceptible to interference and security issues.


Data Line Devices




Data line devices are the devices that connect different networks and devices in a data communication system. They perform various functions such as signal conversion, multiplexing, demultiplexing, modulation, demodulation, amplification, regeneration, etc. Some examples of data line devices are modems, multiplexers, repeaters, hubs, bridges, switches, routers, etc. Modems are devices that convert digital signals into analog signals and vice versa for transmission over analog media such as telephone lines. Multiplexers are devices that combine multiple input signals into one output signal for transmission over a single channel. Demultiplexers are devices that separate one input signal into multiple output signals for distribution over multiple channels. Repeaters are devices that amplify and regenerate weak or distorted signals for transmission over long distances. Hubs are devices that connect multiple devices in a star topology network. Bridges are devices that connect two or more LANs or segments of LANs at the data link layer. Switches are devices that connect multiple devices in a network at the data link layer or higher layers. Routers are devices that connect two or more networks at the network layer.


Error Control




Error control is the process of detecting and correcting errors in data transmission. Errors can occur due to various sources such as noise, interference, distortion, attenuation, etc. Errors can be classified into two types: single-bit errors and burst errors. Single-bit errors are those that affect only one bit in a data unit. Burst errors are those that affect two or more consecutive bits in a data unit. There are two methods for error control: error detection and error correction. Error detection is the process of identifying whether an error has occurred in a data unit or not. Error correction is the process of recovering the original data unit from the erroneous one or requesting a retransmission of the erroneous one. There are various methods and protocols for error detection and correction such as parity check, checksum, cyclic redundancy check (CRC), automatic repeat request (ARQ), forward error correction (FEC), etc.


Network Architecture




Network architecture is the design and structure of a network system. It defines how different components of a network interact with each other to provide communication services and functions. There are some principles and models of network architecture that define how networks are classified and organized into layers. One of the most widely used models is the Open Systems Interconnection (OSI) model, which divides the network functions into seven logical layers: physical, data link, network, transport, session, presentation, and application. Each layer performs a specific task and communicates with the adjacent layers through well-defined interfaces. Another common model is the Transmission Control Protocol/Internet Protocol (TCP/IP) model, which is the basis of the Internet and other networks. The TCP/IP model consists of four layers: network access, internet, transport, and application. The TCP/IP model is simpler and more flexible than the OSI model, but less descriptive and standardized. The Physical Layer




The physical layer is the lowest layer of the network architecture, which deals with the transmission and reception of raw data bits over a physical medium. The physical layer defines the characteristics of the transmission medium, such as its type, bandwidth, attenuation, noise, etc. It also defines how data signals are encoded and modulated to be transmitted over the medium. Encoding is the process of converting data bits into signal elements, such as voltage levels or light pulses. Modulation is the process of varying some property of a carrier signal, such as its amplitude or frequency, according to the data bits. The physical layer also defines how devices are connected to the medium and how they synchronize their clocks and bit rates. Some of the standards and technologies for the physical layer are RS-232, EIA/TIA-568, ISDN, DSL, etc.


The Data Link Layer




The data link layer is the second layer of the network architecture, which deals with the transmission and reception of data frames over a physical link. A data frame is a unit of data that contains a header, a payload, and a trailer. The header contains information such as source and destination addresses, frame type, error control code, etc. The payload contains the actual data to be transmitted. The trailer contains information such as checksum or CRC to detect errors. The data link layer performs various functions such as framing, error control, flow control, medium access control, etc. Framing is the process of dividing a stream of data bits into frames and adding headers and trailers to each frame. Error control is the process of detecting and correcting errors in data frames using methods such as parity check, checksum, CRC, ARQ, FEC, etc. Flow control is the process of regulating the rate of data transmission between two devices to avoid congestion or buffer overflow. Medium access control is the process of coordinating the access of multiple devices to a shared medium using methods such as CSMA/CD, CSMA/CA, token passing, CSMA/CD, CSMA/CA, etc. Local Area Networks




Local area networks (LANs) are networks that connect devices within a limited geographical area, such as a building or a campus. LANs provide high-speed and low-cost communication among devices and enable resource sharing and collaboration. LANs can be designed and implemented using various topologies, such as bus, ring, star, tree, mesh, etc. Each topology has its own advantages and disadvantages in terms of cost, performance, reliability, scalability, etc. LANs can also use different technologies and standards for data transmission, such as IEEE 802.3 Ethernet, IEEE 802.5 Token Ring, IEEE 802.11 Wireless LAN, etc. Each technology and standard has its own characteristics and features in terms of speed, distance, medium access control, error control, security, etc.


Bridges and Layer 2 Switches




Bridges and layer 2 switches are devices that connect two or more LANs or segments of LANs at the data link layer. They perform various functions such as filtering, forwarding, learning, flooding, etc. Filtering is the process of discarding frames that are not destined for another segment. Forwarding is the process of sending frames to the appropriate segment based on the destination address. Learning is the process of building and updating a table that maps MAC addresses to ports. Flooding is the process of sending frames to all ports except the source port when the destination address is unknown or broadcast. Bridges and layer 2 switches have some advantages and disadvantages over each other. Bridges are simpler and cheaper than switches, but they have lower performance and scalability. Switches are faster and more scalable than bridges, but they are more complex and expensive.


Network Layer




The network layer is the third layer of the network architecture, which deals with the transmission and reception of data packets over a network. A data packet is a unit of data that contains a header and a payload. The header contains information such as source and destination addresses, packet type, packet length, etc. The payload contains the data to be transmitted. The network layer performs various functions such as addressing, routing, forwarding, fragmentation, reassembly, etc. Addressing is the process of assigning unique identifiers to devices and networks in a global address space. Routing is the process of finding the best path for data packets to reach their destination. Forwarding is the process of moving data packets from one interface to another interface on a router. Fragmentation is the process of breaking a large data packet into smaller pieces to fit the maximum transmission unit (MTU) of a link. Reassembly is the process of putting the fragmented pieces back together at the destination. The network layer also provides mechanisms for quality of service (QoS), which is the ability to guarantee certain performance parameters such as bandwidth, delay, jitter, etc. Some of the standards and technologies for the network layer are IP, ICMP, ARP, etc.


Virtual Circuit Packet Switching Network




A virtual circuit packet switching network (VCPSN) is a type of packet switching network that establishes a logical connection between the source and destination before sending data packets. A virtual circuit (VC) is a path that consists of a sequence of links and routers along which data packets travel. A VC has a unique identifier that is added to each packet header and used by routers to forward packets along the VC. A VC can be either permanent or switched. A permanent virtual circuit (PVC) is a VC that is established manually by network administrators and remains active until it is terminated. A switched virtual circuit (SVC) is a VC that is established dynamically by network protocols and remains active only for the duration of a communication session. A VCPSN has some advantages and disadvantages over a datagram packet switching network (DPSN), which does not establish any connection before sending data packets.


Internet Protocol (IP)




The Internet Protocol (IP) is one of the main protocols used at the network layer. It is responsible for addressing, routing, and delivering data packets across networks. IP operates on a best-effort basis, which means that it does not guarantee reliable or ordered delivery of data packets. IP also does not provide any error control or flow control mechanisms. These functions are left to higher layer protocols such as TCP or UDP. IP has two versions: IPv4 and IPv6. IPv4 is the most widely used version of IP, which uses 32-bit addresses to identify devices and networks in a global address space. However, IPv4 has some limitations such as address exhaustion, security issues, scalability issues, etc. IPv6 is the newer version of IP, which uses 128-bit addresses to overcome the limitations of IPv4. IPv6 also provides some additional features such as stateless address autoconfiguration, multicast addressing, anycast addressing, etc. 71b2f0854b


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