IB COMPUTER SCIENCE | Network Fundamentals for Topic 3

NETWORKS | NETWORK FUNDAMENTALS

ALSO IN THIS TOPIC
YOU ARE HERE | NETWORK FUNDAMENTALS
DATA TRANSMISSION
WIRELESS NETWORKING
TOPIC 3 REVISION
KEY TERMINOLOGY
NETWORK FUNDAMENTALS ANSWERS

SECTION 1 | WHAT IS A NETWORK

When computer are connected together to share data this is classed as a network. One of the first computer networks was formed in 1969, this was a small local network connecting a series of computers within one room, over the following year computer networks became more and more common and started to cover larger and larger areas. In 1989 Sir Tim Berners-Lee first created what we now know as the the World Wide Web. Sir Tim Berners-Lee wrote web client and server models, worked on URL structure, HTTP (Hypertext Transfer Protocol) and HTML (Hypertext Mark-up Language).

A network is when two or more computers are connected together.

Remember that the World Wide Web and the Internet are two different things. The world wide Web is the protocols, language and webpages we access, whereas the internet is the network that provides a medium for the transfer of data.

There are many different types of networks each with their own purpose, some of which are listed below.

Local Area Network (LAN): A LAN is a network that connects devices within a limited area, such as a home, office, or building. It is typically used for sharing resources such as printers, files, and often includes a web server to connect the LAN to the internet.
Virtual Local Area Network (VLAN): A VLAN is a way to divide a LAN into smaller, virtual networks. It lets network administrators group devices together based on logical connections, rather than where they are physically located, a VLAN could be set up over a limited area or over large geographical areas by using the internet structure for data transfer. This allows administrators to control traffic between devices and improve security by separating them into different groups.
Wide Area Network (WAN): A WAN is a network that spans a larger geographical area than a LAN, typically connecting devices across cities, countries, or even continents. It is used for connecting devices that are geographically dispersed and for sharing resources over a larger area.
Wireless Local Area Network (WLAN): A WLAN is a type of LAN that uses wireless technology to connect devices within a limited area. It is commonly used in homes, schools, and offices to provide wireless internet access to devices such as laptops, smartphones, and tablets.
Personal Area Network (PAN): A PAN is a network that connects devices within a person's immediate proximity, typically within a range of a few meters. It is used for connecting devices such as smartphones, tablets, and wearable devices to each other or to a larger network.
Virtual Private Network (VPN): A VPN is a type of network that allows remote users to securely access a private network over a public network such as the internet. It is commonly used by businesses to provide secure remote access to employees working from home or while traveling.
Storage Area Network (SAN): A SAN is a network that provides access to high-speed storage devices such as hard drives and tape libraries. It is typically used by businesses to store large amounts of data that can be accessed quickly and easily by multiple users.

These networks have various topologies(the way there are configured) the main topologies covered at this level are Ring, Bus/Line, Star, Mesh and Hybrid.

SECTION 2 | NETWORK COMPONENTS

ROUTERS: A Router forwards data between IP addresses, they are commonly used to route a connection between the ISP and the client. When webpages are requested the request is forwarded from the route externally and then when the web packages are receive the router routes the packet to the correct device on the network
ACCESS POINTS: An Access point is used on a network to distribute network access to users
GATEWAYS: A Gateway is used to connect networks that are operating on different protocols or architecture.
SWITCHES: A Switch is used to direct data to its destination, networks contain many switches and data is passed through switch to switch until it reaches its destination.
HUBS: Hubs provide a connection between multiple devices, hubs are not used as much as they used to be, since a hub do not manage the data that flows through it, it simply distributes it to all its outputs. Instead switches are now used more frequently, a switch does manage the data that passes through and directs it to its next location. Generally switches are more secure than hubs.
BRIDGES: A Bridge is used to change the medium of transfer, for example in school network Cat5 copper cables are used inside building and optical cables are used to transfer data between buildings, Bridges are used to link the copper cables to the optical cables.
WORKSTATIONS: A Workstation is a computer connected to the network
NODES: A Node is any device connected to a network
ISP: An ISP or Internet Service Provider provides users with a connection to the internet.
SERVERS: A server is a large powerful computer that is used to manage devices and data flow on a network. It provides a connection to share resources and allows efficient device management such as updating all computers on the network.
PROXY SERVERS: A Proxy server is like a normal server but has the additional feature of managing the data between the LAN and the WAN, the Local Area/Internal network and a Wide Area/External network such as the Internet. The Proxy serve provides a buffer between the two networks, filtering data and storing data so if many computers on the network requests the same data it can distribute from store rather than requesting the same data multiple times, helping network speed and security.

SECTION 3 | NETWORK STANDARDS

Standards play a crucial role in the construction and operation of computer networks. They provide a set of guidelines and rules that ensure that all components of a network work together properly, and that devices from different manufacturers can communicate with each other effectively. Here are some of the key reasons why standards are important in the construction of networks:

Interoperability: Standards ensure that different devices and software can communicate and work together effectively, regardless of their manufacturer. This is important because it allows businesses and individuals to choose from a wide range of products and services, and to integrate them into their existing networks with minimal effort.
Reliability: Standards provide a consistent and reliable way to build networks, ensuring that components are compatible with each other and work as expected. This reduces the risk of compatibility issues, network failures, and downtime.
Scalability: Standards help ensure that networks can grow and evolve over time, without requiring significant changes to the underlying infrastructure. This is important for businesses and organizations that need to adapt their networks to changing needs and technologies.
Security: Standards provide a framework for implementing security measures and protocols that can protect networks from attacks and unauthorized access. This is essential in today's environment, where cyber threats are increasingly common and sophisticated.
Innovation: Standards help foster innovation by creating a level playing field for companies to compete and innovate within. By providing a common set of guidelines and rules, standards can help spur the development of new technologies and solutions that can improve network performance, security, and functionality.

In summary, standards are crucial in the construction and operation of computer networks, as they ensure interoperability, reliability, scalability, security, and innovation. By adhering to industry standards, organizations can build and maintain networks that are robust, secure, and flexible, and that can meet the needs of users and stakeholders over time.

SECTION 4 | OSI MODEL

The Open Systems Interconnection (OSI) Seven Layer Model is a theoretical model that describes how data is transmitted between networked devices. The seven layers are: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

Physical Layer: The lowest layer of the OSI model, responsible for transmitting and receiving raw bitstreams over a physical medium, such as copper wire, fiber optic cable, or wireless transmission.
Data Link Layer: The layer responsible for the reliable transfer of data between two adjacent nodes on a network. This layer is responsible for error detection and correction, and can also manage flow control.
Network Layer: The layer responsible for routing data between different networks. This layer is responsible for addressing and routing data packets between networks, and can perform functions such as fragmentation and reassembly.
Transport Layer: The layer responsible for reliable end-to-end communication between applications running on different hosts. This layer provides services such as connection-oriented or connectionless data transmission, flow control, and error recovery.
Session Layer: The layer responsible for establishing, managing, and terminating communication sessions between applications. This layer manages the dialogue between applications, and can also provide services such as checkpointing and recovery.
Presentation Layer: The layer responsible for representing data in a format that can be understood by applications. This layer can perform functions such as data encryption and decryption, compression and decompression, and data formatting.
Application Layer: The highest layer of the OSI model, responsible for providing application services to users. This layer includes all the protocols and services that support applications, such as email, file transfer, and web browsing.

SECTION 5 | WHAT IS A VPN USED FOR

A VPN (Virtual Private Network) is a technology that allows you to create a secure and encrypted connection between your computer or mobile device and a remote server over the internet. This creates a private network that you can use to access the internet and other resources securely and anonymously, even when using a public Wi-Fi network.

The use of a VPN has several advantages, including:

Security: A VPN encrypts all the data that is transmitted between your device and the remote server, making it difficult for anyone to intercept and access your data. This is particularly important when using public Wi-Fi networks, which are often unsecured and can be easily hacked.
Privacy: A VPN hides your IP address and location from the websites and services you access, making it difficult for them to track your online activity. This helps protect your privacy and anonymity online.
Access to restricted content: A VPN can allow you to access content that is blocked in your region or by your Internet Service Provider (ISP). By connecting to a server in a different location, you can bypass these restrictions and access the content you need.
Remote access: A VPN can provide remote access to a private network, allowing employees to access company resources securely from anywhere in the world.
Cost savings: A VPN can reduce costs associated with expensive private networks and leased lines, making it a cost-effective alternative for businesses and organizations.

The use of a VPN is essential for protecting your online privacy and security, accessing restricted content, and enabling remote access to private networks. By encrypting your internet traffic and hiding your IP address, a VPN provides a secure and private connection to the internet, regardless of your location or the network you are using.

SECTION 6 | COMPONENTS OF A VPN

To provide a Virtual Private Network (VPN), there are several main components that are required:

VPN Client: The VPN client is software that is installed on the user's device, such as a computer or mobile device. It is responsible for establishing the encrypted connection to the remote server and providing access to the VPN.
VPN Server: The VPN server is a remote server that receives the encrypted traffic from the VPN client and decrypts it, allowing access to the internet and other resources. The VPN server also encrypts the traffic that is sent back to the client, providing a secure connection.
VPN Protocol: The VPN protocol is the method used to establish and maintain the secure connection between the client and the server. Common VPN protocols include OpenVPN, IKEv2, and L2TP/IPsec.
Authentication: Authentication is the process of verifying the identity of the user or device that is attempting to connect to the VPN. This can be done using a username and password, digital certificates, or other methods.
Encryption: Encryption is used to protect the data that is transmitted between the client and the server. This ensures that the data cannot be intercepted and read by unauthorized parties.

By using these components together, a VPN can provide a secure and private connection to the internet and other resources, protecting the user's privacy and security.

VPN's use a method of tunnelling which is the process of encapsulating one protocol within another protocol for secure data transmission over an insecure network. It involves creating a tunnel or virtual pipe between two devices, where data is encrypted and then transmitted through the tunnel.

The process of tunnelling involves the following steps:

A connection is established between the two devices that want to communicate.
The data to be transmitted is encapsulated within another protocol, creating a new packet that contains the original data.
The new packet is then encrypted to secure the data and protect it from unauthorized access.
The encrypted packet is then transmitted through the tunnel to the destination device.
Upon arrival, the packet is decrypted, and the original data is extracted.

Tunnelling allows for secure transmission of data over an insecure network such as the internet. By encapsulating and encrypting the data, it provides an additional layer of security, making it more difficult for attackers to intercept and access sensitive information.

ALSO IN THIS TOPIC

NETWORK FUNDAMENTALS
DATA TRANSMISSION
WIRELESS NETWORKING
TOPIC 3 REVISION
KEY TERMINOLOGY
NETWORK FUNDAMENTALS ANSWERS