VJC Chapter 26 Fundamentals of Computer Networks (Part 1)

VJC/H2Computing/9569 Chapter 26 Fundamentals of Computer Networks (Part 1) Content 1 Computer Network 2 Types of Computer Networks 2.1 Local Area Network 2.2 Metropolitan Area Network 2.3 Wide Area Network 2.4 Intranet 2.5 Internet 2.6 Intranet vs Internet 3 Network Hardware 4 Network Addresses 4.1 Media Access Control Address 4.2 Internet Protocol Address 4.3 MAC vs IPv4 vs IPv6 5 Domain Name Service 6 Transmission Control Protocol/Internet Protocol Model 6.1 TCP/IP protocol suite 6.2 Transmission Control Protocol 6.3 Internet Protocol 6.4 Ethernet Protocol 6.5 Other protocols 7 Transmission mode 7.1 Circuit switching 7.2 Packet switching 7.2.1 Packet Header 7.2.2 Packet loss 7.2.3 Routing tables 7.3 Packet switching vs Circuit switching Annex – HTTP, FTP, SMTP, POP, IMAP References Syllabus Learning Outcomes 4.1 Fundamentals of Computer Networks Understand computer network technology 4.1.1 Explain the concepts of LAN, WAN, intranet, and the structure of the internet. 4.1.2 Understand the concepts of IP addressing and domain name server (DNS). 4.1.3 Explain the need for communication protocols in a network. 4.1.4 Explain how data is transmitted in a packet-switching network. 1

VJC/H2Computing/9569 1 Computer Network A computer network is a system of two or more computers that are connected together by a transmission medium for the exchange of data. 2 Types of Computer Networks Computer networks can be classified according to their geographical size, transmission medium and network organisation type. 2.1 Local Area Network A local area network (LAN) is a network of computing devices connected within a small geographical area, typically within the same building, such as a home, school, office or building. Due to the small number of connections supported and the close proximity of the devices, LANs typically provide faster data transfer than the other networks. Devices on a LAN can easily share resources like printers, files, and applications. A WLAN is the wireless version of a LAN. 2.2 Metropolitan Area Network A metropolitan area network (MAN) is a network of computing devices covering a larger geographical area (two or more buildings within the same town or city) than a LAN. A MAN is typically owned and operated by a large organisation such as a cities, business or government body. 2

VJC/H2Computing/9569 2.3 Wide Area Network A wide area network (WAN) is a network of computing devices covering a large-scale geographical area, typically across multiple geographical locations. A WAN generally consists of multiple smaller networks such as LANs or MANs. A WAN differs from a LAN in several ways. Unlike a LAN, a WAN is not limited to a single geographical location and can span long distances via long-range transmission media such as telephone lines, fibre optic cables or satellite links. A WAN also uses more expensive and high-speed technology than a LAN. WANs can be either private or public. Private WANs are built and maintained by large multinational companies and government organisations. The internet is an example of a public WAN and is considered as the largest WAN in the world. 2.4 Intranet An intranet is a private network built within an organisation, like a company, school, or government agency. Access to the intranet is typically restricted to authorised users within the organisation. This allows them to share information and resources securely within a controlled environment. Intranets are often used to host internal resources like company documents, employee portals, collaboration tools, and communication platforms. Since access is restricted, intranets offer a more secure environment for sharing sensitive information compared to the public internet. 2.5 Internet The internet is a global, public network accessible to anyone with an internet connection. It is a network of networks linked by a broad array of electronic, wireless, and optical networking technologies. It is essentially an infrastructure that provides services to applications. The internet functions through a layered system, with data traveling in packets across various networks based on unique IP addresses. Routers act as traffic directors, guiding this data flow, while Internet Service Providers provide the connection devices and this vast network. This complex system allows for global communication, information sharing, and access to a multitude of online resources and services. 3

VJC/H2Computing/9569 Source: Kurose, J., & Ross, K. (2016). Computer Networking: A Top-Down Approach (7th ed.). Pearson. 2.6 Intranet vs Internet Feature Intranet Internet Scope Private network within an organization Public network accessible globally Access Restricted to authorized users within the organization Open to anyone with an internet connection Content Internal resources relevant to the organization (documents, portals, tools) Diverse content from various sources (news, social media, entertainment) Security More secure due to restricted access Less secure due to open nature Connection Can be isolated from the internet or connected with security measures Connects devices across the globe Purpose Internal communication, collaboration, secure resource sharing Global communication, information sharing, access to online services 4

VJC/H2Computing/9569 3 Network Hardware Network hardware refers to the physical components that make up a computer network. These components work together to enable devices to communicate and share resources. Some essential network hardware includes: ● Computers with Network Interface Cards (NICs) A network interface controller (NIC) provides the hardware interface to enable the transfer of data between a device and a network. An NIC may connect to a network physically or wirelessly. Most devices are equipped with a built-in NICs, one for Ethernet and one for Wi-Fi. The NIC should come with driver software that the operating system automatically configures and updates. Each NIC has a unique ‘physical’ address. This is sometimes referred to as the MAC address (explained later in the chapter). NIC gives a device its identification on the network. If the NIC is removed and inserted into a different device, the new device takes the address with it. ● Cables Unshielded Twisted Pair (UTP) cables are the standard (CatX cables, where X is a number that indicates the speed a cable will fetch). For fast speeds, fibre optic cables are used. ● Hubs A network hub is the simplest way to connect multip