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C S 0 0 1 Computer Networks 1 Computer Networks A computer network facilitates interaction among end-users through various modes C S 0 0 1 such as phone, email, instant messaging, or video calls. It also allows for the sharing of resources, including printers, storage, and software, in addition to p...

C S 0 0 1 Computer Networks 1 Computer Networks A computer network facilitates interaction among end-users through various modes C S 0 0 1 such as phone, email, instant messaging, or video calls. It also allows for the sharing of resources, including printers, storage, and software, in addition to providing enhanced storage capabilities. 2 Computer Networks Definition of a computer network A computer network is a set of interconnected computers that can share data, resources, and services. C S 0 0 1 This interconnection allows for communication and collaboration between different devices, often over significant distances, by following a set of rules and protocols to send and receive information. These networks can range from small local area networks in a home or office to vast global networks such as the internet. 3 Computer Networks Basic concepts and terminology In the computer networking, several fundamental concepts and terminologies are foundational to understanding how networks operate. Here is a brief overview of some of these basic terms: Node C S 0 0 1 A node is any device connected to a network such as a computer, printer, or any other device capable of sending or receiving data. 4 Computer Networks Basic concepts and terminology Network Interface Cards (NICs) are hardware components that allow computers to connect to a network. They act as the interface between the computer's internal circuitry and the network cables or wireless signals, facilitating data transmission between the two. C S 0 0 1 Wireless NIC Wired NIC 5 Computer Networks Basic concepts and terminology Data Packet A packet is a formatted unit of data carried by a packet-switched network. In networking, data is typically broken down into manageable packets before transmission. C S 0 0 1 Sender packets Receiver 6 Computer Networks Basic concepts and terminology Protocol A protocol is a set of rules governing the format and transmission of data. Examples include the Transmission Control Protocol (TCP) and the Internet Protocol (IP). C S 0 0 1 Set of rules Sender Receiver 7 Computer Networks Basic concepts and terminology IP Address An Internet Protocol (IP) Address is a unique string of numbers separated by periods or colons that identifies each computer using the IP to communicate over a network. C S 0 0 1 123.25.91.7 4 parts 3 periods Each part has number (0-255) 8 Computer Networks Basic concepts and terminology MAC Address A MAC (Media Access Control) address is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. C S 0 0 1 Structure: Length: 48 bits. Format: It's usually represented as six groups of two hexadecimal digits, separated by colons (e.g., 00:1A:2B:3C:4D:5E) or hyphens (e.g., 00-1A-2B-3C-4D-5E). 9 Computer Networks Basic concepts and terminology Bandwidth refers to the maximum rate of data transfer across a network or internet connection. It determines how much data can be sent C S 0 0 1 data Receiver Sender over a specific connection in a given amount of time. Bandwidth is typically D A T a measured in bits per second (bps) or its higher multiples such as Mbps (megabits Sender Receiver per second) or Gbps (gigabits per second). 10 Computer Networks Basic concepts and terminology Router A router connects multiple networks together and routes data packets between them. Typically used in homes and businesses to connect the local network to the internet and to route traffic between different networks. C S 0 0 1 Router Switch A switch connects devices within a single network, using Switch MAC addresses to forward data to the appropriate device. Commonly used in businesses, data centers, and large networks to connect multiple devices within the same local network. 11 Computer Networks Basic concepts and terminology Hub Is a basic networking device that connects multiple devices in a local area network (LAN). It broadcasts C S 0 0 1 Hub data to all connected devices. Can cause network congestion due to broadcasting to all devices. Key Difference between hub and switch : A switch is more efficient than a hub as it sends data only to the intended recipient, whereas a hub broadcasts data to all devices. 12 Computer Networks Basic concepts and terminology Physical cabling Physical cabling serves as the backbone of a network's infrastructure, enabling the transfer of data between different devices within the network. There are C S 0 0 1 several types of physical cables used in networking, each suitable for different requirements and network environments. Here is an overview of common network cable types: Twisted Pair Cable. Coaxial Cable. Fiber Optic Cable. 13 Computer Networks Basic concepts and terminology Physical cabling Twisted Pair Cable 1.Unshielded Twisted Pair (UTP): The most common type of networking cable. It's composed of pairs of wires C S 0 0 1 twisted together to reduce electromagnetic interference. UTP comes in different categories, such as CAT5e, CAT6 and CAT7, each supporting different speeds and bandwidths. 2.Shielded Twisted Pair (STP): Like UTP, but each pair of wires is additionally shielded by foil to provide better protection against electromagnetic interference. 14 Computer Networks Basic concepts and terminology Physical cabling Coaxial Cable Used for cable internet connections and cable television. It has a single copper conductor at its center, a plastic layer providing C S 0 0 1 insulation between the conductor and a braided metal shield. Fiber Optic Cable Transmits data as light, allowing for very high transmission speeds and longer distances than wire cables. It's immune to electromagnetic interference and is used for backbones, long- distance communication. 15 Computer Networks Basic concepts and terminology Physical cabling Considerations for Network Cabling: Distance: Cable types have maximum distance ratings; fiber optics provide the longest reach. C S 0 0 1 Interference: Environments with heavy machinery or fluorescent lighting might require shielded cabling. Cost: Fiber optics provide high bandwidth and immunity to interference but can be more costly than copper cables. Installation: Some cables are more flexible and easier to install through conduits and tight spaces, while others are more fragile and require careful handling, such as fiber optic cables. 16 Computer Networks Benefits of networks Benefits of Computer Networks: 1.Communication: Networks enable real-time communication, be it through emails, instant messaging, or video calls. 2.Resource Sharing: Enabling multiple devices to use the same hardware resources (like printers and scanners) or software applications. C S 0 0 1 3.Storage: Providing centralized data storage, which can be more secure and economical than maintaining data across numerous individual devices. 4.Cost-Effectiveness: Reduces the cost of operations by centralizing resources and infrastructure, thereby cutting down on hardware and software expenses. 5.Collaboration: Promotes collaborative efforts across different geographic locations, allowing multiple people to work on the same documents or projects. 17 C S 0 0 1 Computer Networks 18 Computer Networks Types of Computer Networks Computer networks can be categorized based on their size, range, and structure. Here are the primary types of networks you will encounter: 1.Local Area Network (LAN) Description: LANs are networks confined to a small geographic area, like a single building or a C S 0 0 1 campus. They are typically owned, controlled, and managed by a single person or organization. Features: High transfer speeds, low latency, and LAN relatively easy to manage. Uses technologies such as Ethernet and Wi-Fi. Usage: Office buildings, homes, schools, and laboratories. 19 Computer Networks Types of Computer Networks 2.Wide Area Network (WAN) Description: WANs encompass broad geographic areas, crossing city, regional, or LAN national boundaries. The internet is the largest WAN, spanning the entire globe. C S 0 0 1 Features: Lower speed compared to LANs WAN and higher latency. They commonly use LAN routers and are not restricted to a single LAN organization. Usage: Used for multinational businesses, government agencies, and when connecting disparate LANs. 20 Computer Networks Types of Computer Networks 3. Metropolitan Area Network (MAN) Description: A MAN spans a larger city area than a LAN but is typically confined to a single metropolitan area, LAN city, or town. C S 0 0 1 Features: It is larger than a LAN and Man often combines multiple LANs into a LAN single larger network, which enables efficient sharing of regional resources. Usage: City-wide LAN government networks, large universities. 21 Computer Networks Network Topologies Network topology refers to the layout pattern of interconnections among the various elements (nodes, links, etc.) of a computer network. It can also refer to the physical or logical way in which the network is wired. Here's a common C S 0 0 1 network topologies: Bus. Star. Ring. Mesh. 22 Computer Networks Network Topologies Bus Topology Structure: All devices are connected to a single central cable, known as the bus or backbone. advantage: Easy to implement and extend; requires less cable than other topologies. C S 0 0 1 disadvantage: The failure of the central cable will bring down the entire network. Limited cable length and number of stations. 23 Computer Networks Network Topologies Star Topology Structure: All devices are connected to a central hub. The hub can be a hub or switch which acts as a conduit to transmit messages. advantage : Easy to install and manage. Failure of one node does not affect the rest of the network. C S 0 0 1 disadvantage: If the central hub fails, the whole network is inoperable. Requires more cable than bus topology. 24 Computer Networks Network Topologies Ring Topology Structure: Each device is connected to two other devices, forming a circular data path. Messages travel around the ring until they reach their destination. C S 0 0 1 advantage : Data is quickly transferred without a central hub. Adding additional nodes has little impact on bandwidth. disadvantage: A break in the ring (such as a failure in any single workstation or cable) can result in network failure. 25 Computer Networks Network Topologies Mesh Topology Structure: Every device is connected to every other device on the network, providing multiple pathways for data to travel. advantage : Highly reliable, as there is no single point of failure. Provides robust fault tolerance and ease of troubleshooting. C S 0 0 1 disadvantage: Costly and complex due to the amount of cabling and the number of I/O ports required. 26 Computer Networks Models of network In networking, the two primary models of network architecture are client-server and peer-to-peer (P2P). Each has distinct features, advantages, and disadvantages, making them suitable for different situations. C S 0 0 1 Client-Server Network: In a client-server network, one or more central servers provide services to the client computers. These services can include access to web pages, data storage, email, or other resources. 27 Computer Networks Models of network Client-Server Network: Features: Centralized server(s) that manage resources and security. Clients request services from the server. Can be expanded to serve many clients. C S 0 0 1 Servers are often more powerful than clients and are dedicated to their tasks. 28 Computer Networks Models of network Client-Server Network: Advantages: Centralized control over the network, including security and updates. Easier to backup and manage data. Efficient resource sharing. C S 0 0 1 Disadvantages: Server dependence means that if the server goes down, the services it provides become unavailable. Can be expensive to set up and maintain due to the need for powerful server hardware and software. 29 Computer Networks Models of network Peer-to-Peer Network: In a peer-to-peer network, each computer, known as a peer, can act as both a client and a server. Peers share resources among each other without the need for a centralized server. C S 0 0 1 Features: No central server; all computers are equal and operate both as client and server. Direct sharing of files and resources between peers. Simple to configure and less costly to set up. 30 Computer Networks Models of network Peer-to-Peer Network: Advantages: Reduced costs since there is no need for a server. Easy setup and maintenance. Each user has control over their own shared resources. C S 0 0 1 Disadvantages: Not ideal for large networks; can become inefficient as the network grows. Each peer must manage its own security. Lack of centralized backups can lead to data redundancy issues. 31 Computer Networks Network Protocols and the OSI Model Network protocols are sets of established rules that dictate how to format, transmit, and receive data so computer network devices can communicate regardless of the differences in their underlying infrastructures, designs, or standards. The most important protocols in networking can vary depending on context and use, but generally, the Internet Protocol (IP) and the Transmission C S 0 0 1 Control Protocol (TCP) are among the most crucial for the functioning of the internet and most networks. 32 Computer Networks Network Protocols and the OSI Model TCP/IP (Transmission Control Protocol/Internet Protocol): This is the foundational communication protocol suite of the internet and most local networks, defining how data should be packetized, addressed, transmitted, routed, and received. C S 0 0 1 HTTP (Hypertext Transfer Protocol): HTTP is used for transferring web pages on the internet. When a user accesses a web page, HTTP is the protocol that delivers the page from the server to the user’s browser. HTTPS (HTTP Secure): An extension of HTTP, it is used for secure communication over a computer network within a web browser. 33 Computer Networks Network Protocols and the OSI Model FTP (File Transfer Protocol): As its name suggests, FTP is used for the transfer of files between a client and a server on a network. DNS (Domain Name System): DNS translates humanC S 0 0 1 readable domain names (like www.example.com) into machine-readable IP addresses. DHCP (Dynamic Host Configuration Protocol): DHCP automatically assigns a dynamic IP address to each device on a network so they can communicate with other IP networks. 34 Computer Networks Network Protocols and the OSI Model The OSI Model: The Open Systems Interconnection (OSI) model is a conceptual framework used to understand and implement standard protocols to facilitate interoperability in networking. It divides the networking process into seven layers: C S 0 0 1 1.Physical Layer: Concerned with the transmission and reception of the unstructured raw bit stream over a physical medium. 2.Data Link Layer: Provides node-to-node data transfer—a link between two directly connected nodes. It also handles error correction from the physical layer. 35 Computer Networks Network Protocols and the OSI Model The OSI Model: 3.Network Layer: Handles the routing of the data (sending it in the right direction to the correct destination on outgoing transmissions and receiving incoming transmissions at the packet level). C S 0 0 1 4.Transport Layer: Provides transparent transfer of data between end systems, or hosts, and is responsible for end-to-end error recovery and flow control. 5.Session Layer: Controls the connections between computers. It establishes, manages, and terminates the connections between the local and remote application. 36 Computer Networks Network Protocols and the OSI Model The OSI Model: 6.Presentation Layer: Translates data between the application layer and the network format. It ensures that data is in a usable format and is where data encryption occurs. C S 0 0 1 7.Application Layer: Is the closest layer to the end user, which means both the OSI application layer, and the user interact directly with the software application. This layer interacts with software applications that implement a communicating component. 37 Computer Networks Network Protocols and the OSI Model Receiver Sender C S 0 0 1 Application Layer 7 Application Presentation Layer 6 Presentation Session Layer 5 Session Transport Layer 4 Transport Network Layer 3 Network Data Link Layer 2 Data Link Physical Layer 1 Physical 38