Network Communication Quiz

Computer Networks (CN)

• Computer networks are digital telecommunications networks enabling nodes to share resources.
• Shared resources include software, files, data, storage, printers, scanners, fax machines, and modems.
• Communication involves a sender transmitting a message to a receiver.

OSI Model

• The OSI model is a seven-layer reference model for network architecture.
• It's not an implemented model but a guideline.
• Layers include Application, Presentation, Session, Transport, Network, Data Link, and Physical.
• The Application, Presentation, and Session layers handle host concerns.
• The Transport, Network, and Data Link layers handle network concerns.
• The Physical layer manages the transmission medium.

TCP/IP Model

• The TCP/IP model (four or five layers) is an implemented model used in the Internet.
• Layers include Application, Transport, Network (Internet), and Data Link and Physical.

Course Objectives

• Introduce concepts, terminologies, and technologies used in data communication and computer networks.
• Explain connecting device basics and data link layer protocols.
• Understand addressing and routing protocols.
• Learn transport layer process-to-process delivery, protocols, congestion control, and applications.

Course Outcomes

• Understand data communication and networking principles.
• Gain knowledge of data link control (flow and error control).
• Learn two prevalent wireless LAN technologies: IEEE 802.11 and Bluetooth.
• Gain knowledge of addressing, routing for network, transport, and application layer protocols.
• Learn cryptography and internet security basics.

Unit 1: Physical Layer

• Covers data communications, network models (OSI and TCP/IP), and addressing.
• Includes guided and unguided transmission media, switching (circuit switched, datagram, virtual circuit).
• Discusses cable networks for data transmission (dial-up modems, DSL, cable TV).

Unit 2: Data Link Layer

• Discusses data link control (framing, flow and error control, protocols for noiseless/noisy channels, HDLC).
• Covers multiple access (random and controlled access).
• Includes wired LANs (Ethernet: IEEE standards, Fast Ethernet, Gigabit Ethernet), introduction to wireless LANs (IEEE 802.11, Bluetooth), and connecting LANs (devices, backbone networks, virtual LANs).

Unit 3: Network and Transport Layer

• Covers logical addressing (IPv4 and IPv6), internet protocol (internetworking, IPv4, IPv6).
• Includes address mapping (ARP, RARP, BOOTP, DHCP, ICMP, IGMP).
• Discusses delivery (forwarding, routing, unicast, multicast routing protocols).
• Covers transport layer process-to-process delivery and UDP/TCP protocols.

Unit 4: Application Layer and Network Security

• Covers application layer (Domain Name System (DNS), e-mail, FTP, WWW and HTTP multimedia).
• Includes network security, service mechanisms and attacks, symmetric key cryptography, asymmetric key cryptography, internet security, and firewalls.

List of Experiments

• Windows Server Operating System and LAN implementation
• Web and FTP services installation and configuration
• Network protocol analyzer study
• TCP/IP network packet transfer and exchange examination
• Shortest Path algorithm implementation program
• Wireless LAN study
• Encryption and decryption program development

Learning Resources

• Behrouz A. Forouzan, "Data communication and Networking" (4th edition, TMH, 2006)
• Andrew S. Tannenbaum, "Computer Networks" (Pearson Education, 2003)

Reference Books

• Wayne Tomasi, "Introduction to Data Communication and Networking" (Pearson Education, 1/e)
• James F. Kurose & Keith W. Ross, "Computer Networking: A Top-Down Approach Featuring Internet Technologies"
• William Stallings, "Cryptography and Network Security: Principles and Practices"
• Greg Tomshon, Ed Tittel, David Johnson, "Guide to Networking Essentials"

Assessment Scheme

• This describes various assessment components (assignments, mid-term tests, quizzes, laboratory continuous assessment [LCA], and end-term examinations [with weightage]).

Chapter 1 – Introduction

• Introduces the concepts of communication at a distance (telecommunication) and examples (telephony, telegraphy, TV).
• Defines data communications (exchange of data between devices), communication systems (combination of hardware and software).
• Provides a definition for data (information presented in a form agreed upon by parties using it).
• Presents fundamental characteristics of effective data communications (delivery, accuracy, timeliness, real-time [audio/video], and non-real-time [e-mail/SMS/WhatsApp]).
• Introduces jitter (packet arrival time variation) in data communication.
• Explains the five components of data communication: message, sender, medium, receiver, and protocol.
• Describes different transmission media (wireline, wireless, RF-link, radio, TV, satellite, radar, and mobile communication).
• Defines different data flow types (simplex, half-duplex, and full-duplex).
• Introduces the concept of networks (a set of interconnected devices with communication links).

Network Criteria

• Discusses the key criteria for a network: performance, reliability, and security.

Performance Criteria

• Discusses how performance is measured, including transit time and response time.
• Presents network factors like the number of users, type of transmission medium, hardware capabilities, and software efficiency, which are evaluated using throughput and delay metrics.

Reliability Criteria

• Explains the reliability measure as the frequency of failure and the time to recover from any failure.
• Explains security as protecting data from unauthorized access, damage, and development along with its policies and procedures for any data recovery and losses.

Physical Structures

• These are devoted to network topologies.
• Discusses Point-to-Point: Dedicated link, entire capacity dedicated between two devices.
• Discusses Multipoint (Multidrop): Sharing of a single link among multiple devices (spatial/temporal).

Physical Topology

• Physical topology/geometric representation of network links, nodes and how 2 or more links, nodes are used to form a topology to achieve network architecture.
• Presents the four types of topology: Mesh, Star, Bus, and Ring.

Mesh Topology

• Every device connected to every other device. This requires a dedicated line.
• Physical links are 'n(n-1)'.
• Duplex-mode links are '{n(n-1)}/2'.
• Input/output ports = n-1 (for a network with n devices)
• Advantages include removing traffic congestion problems (since connections are dedicated), and robustness. If one link breaks, it doesn't affect other connections. Another advantage is security.
• Disadvantages include needing a large number of cables and I/O ports and increased installation and reconnection difficulties.
• Practical example - connecting regional telephone offices or networks.

Star Topology

• Each device has a dedicated link to only one central controller (hub).
• Advantages include expense, cabling necessities, reliability since the failure of one link will only affect the device connected to the hub it's connected to, and ease of fault identification and isolation.
• Disadvantages include dependence on the central controller (if the hub breaks, the network breaks).
• Practical example :- Local Area Network (LAN).

Bus Topology

• Uses one central cable as a backbone to connect all devices.
• Advantages include ease of installation, minimal cabling costs and efficient network path.
• Disadvantages include fault isolation problems, reconnection issues, and the difficulty in adding or deleting devices.
• Practical example - Ethernet LAN.

Ring Topology

• Each device has a dedicated link to only its two immediate neighbors.
• Signal is passed one direction through the entire ring. Each device includes a repeater that regenerates the bits of a signal intended for another device.
• Advantages include ease of installation and reconfiguration (changing only two connections). Only constraints are media and traffic considerations (maximum ring length and number of devices). Fault isolation is simplified (this can be managed by a network manager).
• Disadvantages include unidirectional traffic (disadvantage) and potential network/link problems (from disabled stations).

Hybrid Topology

• Combination of topologies to meet specific needs for cost efficiency.

Categories of Networks

• LAN (Local Area Network): Limited geographical area (e.g., home office, campus).
• MAN (Metropolitan Area Network): Larger area than LAN, spans a town or city.
• WAN (Wide Area Network): Spans a wide geographical area; e.g. worldwide.
• PAN (Personal Area Network): Covers a small area and connects personal devices.

Network Models

• OSI model: Seven-layer reference model.
• TCP/IP model: Four-layer implementation (or five layer) model used in the Internet.

Protocols and Standards

• Protocols are rules that govern data communications within a network.
• Standards provide rules and guidelines to guarantee interoperability among network devices.
• Protocols include syntax (structure and format of data), semantics (interpretation of bits), and timing (when and how data is sent).
• Standards organizations include ISO, ITU, ANSI, IEEE, and EIA.

Physical Layer

• Responsible for movement of individual bits from one node to another device.
• Contains the physical characteristics of interfaces and medium, representation of bits, data rates, synchronization of bits, line configuration, physical topology, and transmission modes.

Data Link Layer

• Responsible for moving frames from one node to the next.
• It involves framing (dividing data into frames), physical addressing, and flow control to prevent overwhelming the receiver.
• It also includes handling error control to ensure reliability.
• Access control mechanisms determine which device has control over the link during transmission.

Network Layer

• Responsible for delivery of individual packets from the source host to the destination host in networks.
• The network layer adds the logical addressing of the sender and receiver in the header of the frame.
• Routing mechanisms are used to direct traffic between networks.

Transport Layer

• Responsible for message delivery between processes in networked hosts.
• Has connection control and provides segments and sequence numbers to manage data transmission.
• Implements mechanisms for flow and error control at the end-to-end level instead of only a link-level.

Session Layer

• Controls the communication between processes, enabling half or full-duplex communication.
• Implements synchronization points or checkpoints in data transmission.

Presentation Layer

• Handles data translation, compression, and encryption.
• Supports different syntax and semantic formats, allowing different computer systems to communicate.

Application Layer

• Provides services to the user to interact with the network, enabling user interfaces in services such as email, remote file access/transfer, shared database management, and distributed information services, as well as applications.

Internet Service Providers (ISPs)

• Allow users to access and connect to networks to use the internet. They are grouped as local, regional, national, and international.

Switching

• Circuit switching: Establishes a dedicated connection between devices before communication begins.
• Packet switching: Data is broken into packets for transmission.
• Multiconnections (Bus Topology): One link shared with multiple devices; distance and number of devices increase beyond media capacity causing inefficiencies.
• Better solution: Switching.

Packet-Switched Networks

• Packet switching: Data is broken into packets for transmission.
• Datagrams are transmitted independently across the network. Routes for each packet are determined dynamically by routers based on current network state.

Datagram Networks

• Packet switching: Data is broken into packets for transmission.
• Datagrams are an independent method of data transmission across the network. Route determination occurs for each packet individually, based on current network conditions. Each packet's route can vary, and packets can arrive out of order.

Virtual Circuit Networks

• A cross between a circuit and datagram network. Has setup and teardown phases.
• The switch takes the frame or packet in, and given its own virtual circuit identifier (VCI), the new VCI is then put on the next segment of the path until it reaches the destination. The switch also includes a global addressing scheme to uniquely identify source and destination.
• Advantages include better efficiency (compared to circuit switching) with more resources allocated only when needed, but total delays are greater than in virtual circuit networks.

Addressing

• Physical addresses (e.g., MAC address, link addresses) identify a device or node on a specific network.
• Logical addresses (e.g., IP address) provide a universal way to identify and locate nodes on an internetwork.
• Port addresses (specific ports or numbers) identify a process to receive data within a computer.
• Specific addresses (e.g., domain name) are the names of locations or organizations that are universally unique over a world wide network (e.g. domain names).

Transmission Media

• Guided media: uses physical conductors (UTP cable, coaxial cable, fiber-optic cable).
• Unguided media: Wireless EM waves (radio waves, microwaves, infrared).

UTP Cable

• A type of guided transmission medium using twisted-pair wires.
• Advantages include lower cost, ease of installation and use. Disadvantages include potential interference and smaller Bandwidth.

Coaxial Cable

• A type of guided transmission medium.
• Advantages include higher frequency signals, larger Bandwidth, and resistance to signal interference.
• Disadvantages include more expensive, bulky size.

Fiber Optic Cable

• A type of guided transmission medium using optical fibers.
• Advantages include higher bandwidth, lower signal attenuation, and resistance to electromagnetic interference.
• Disadvantages include higher cost and requires complex installation and maintenance expertise.

RF Wave Propagation

• Radio waves: Omnidirectional antenna (360-degree coverage).
• Microwave: Unidirectional antenna.
• Infrared: Short-range line-of-sight communication.

Cable TV Networks

• Cable television networks use coaxial cables for transmission.
• Communication is generally unidirectional in traditional cable TV networks.
• Combination of optical fiber and coaxial cable is used for HFC (hybrid fiber-coaxial) networks.

Bandwidth

• RF wave bandwidth used in data transfer.

Summary of DSL Technologies

• xDSL technologies are available in ADSL, ADSL Lite, HDSL, SDSL, and VDSL with varying upstream/downstream rates, distances, number of twisted pairs and line codes.

Test your understanding of network devices and communication methods with this quiz. It covers various aspects of network performance, topologies, and data transmission types. Perfect for students studying networking concepts and protocols.