Networks

Identify different types of networks

local area network (LAN), virtual local area network (VLAN), wide area network (WAN), storage area network (SAN), wireless local area network (WLAN), internet, extranet, virtual private network (VPN), personal area network (PAN), peer-to-peer (P2P)

Outline the importance of standards in the construction of networks

Standards allow devices to communicate with each other, providing a common ground for manufacturers to build systems and enabling interconnectivity between products from different manufacturers.

Describe how communication over networks is broken down into different layers

The Application layer provides interfaces for user applications to access network services, such as email, file transfer, and web browsing.The Presentation layer handles data representation, translation, encryption, and compression to ensure data exchanged between applications is in a format understood by both sender and receiver.The Session layer establishes, manages, and terminates communication sessions between applications, ensuring reliable data exchange.The Transport layer ensures end-to-end communication between devices, providing error detection, recovery, and reliable data delivery.The Network layer is responsible for routing and forwarding data packets between networks, handling addressing, and determining the optimal path for data transmission.The Data Link layer provides error detection and correction, data framing, and flow control to ensure reliable communication over the physical medium.The Physical layer deals with the transmission and reception of raw data bits over a physical medium, such as cables or wireless signals.

Identify the technologies required to provide a VPN

• Two endpoints

• Authentication protocol– verifying the identity of each end point

• Connection protocol(s) to connect the two endpoints and create the VPN tunnel

• Encryption protocol to secure the tunnel (i.e.  Nobody can read the packets in the tunnel)

Evaluate the use of a VPN

A VPN allows users to connect to a protected LAN through the internet, enabling workers to access a company’s internal network from anywhere in the world.

protocol

a set of standards that allow devices to communicate, governing data transmission, including the format of data packets, addressing, and transmission speed. TCP/IP is a commonly used set of protocols

data packet

a formatted unit of data carried by a packet-switched network. Data is broken into small pieces (packets), sent separately, and reassembled at the destination to complete the message;  consists of a header (source/destination address and packet position), the body (payload), and a footer (indicating the end of the packet)

Explain why protocols are necessary

Protocols are the set of rules computers follow when communicating across a network. Without them, no information can be transmitted, as computers wouldn’t know how to interpret the signals.

Explain why the speed of data transmission across a network can vary

• Download and upload speed/bandwidth of the client

• Download and upload speed/bandwidth of the server

• Amount of traffic across the network

  • Your local network

  • The ISP’s network

  • The Internet itself

• Demand for the network or web resource

  • It takes longer to access something that is being accessed by everybody

Explain why compression of data is often necessary when transmitting across a network

• Compress / shrink the size of a file

• Transfer is faster because the data is smaller and will take less time to send completely

Outline the characteristics of different transmission media

UTP cable offers OK security (if encrypted), is susceptible to electromagnetic interference (EMI), costs less than £1 per metre, and has a speed of 100Mbps to 1Gbps.Fibre-optic cable is highly secure, generally fragile, costs between £2 and £8 per metre, and offers speeds of 5Gbps to 100Gbps.Wireless transmission via radio waves is insecure unless encrypted, susceptible to interference, technically free, and offers speeds of 5Mbps to 200Mbps

Explain how data is transmitted by packet switching

Data is divided into small, fixed-size packets, each containing a portion of the original data along with header information.Each packet is routed independently through the network based on its header information. Routers make dynamic routing decisions to determine the best path for each packet.Packets are transmitted individually, potentially taking different paths and arriving out of order. Upon arrival, the receiving device reassembles them into the original data using information from the packet headers.

Outline the advantages and disadvantages of wireless networks

Advantages include using unlicensed radio spectrum, no need for cables, support for roaming between access points, minimal setup costs, and affordability of wireless devices. Disadvantages include security issues (vulnerability to packet sniffing), interference (crowded 2.4GHz spectrum), limited range, data theft risks from access points, and health concerns regarding radio waves.

Describe the hardware and software components of a wireless network

The hardware components of a wireless network include nodes (PC, laptop, tablet, printer), Wireless Network Interface Card (WNIC), radio waves (bluetooth/Wi-Fi), and connection points like wireless access points (AP) or routers.The software components include the network operating system (with drivers), protocol stack (such as TCP/IP), and applications (such as browsers and file explorers).

Describe the characteristics of wireless networks

• Wireless network card

  • Network card w/ an antenna

• Wireless router or access point

  • Access point may be physically wired to a router

• Signal

  • Strong enough signal to communicate

  • Stronger signals have less packet loss

  • WiFi

    • Trademarked name for marketing by Wireless Ethernet Compatibility Alliance (Wi-Fi Alliance)

    • IEEE 802.11b Direct Sequence

    • WiMAX (Worldwide Interoperability for Microwave Access)

    • Wi-Fi standard designed for 30-40 Mbit/s wireless transfer

    • WiMAX updated to 1 Gbit/s transfer

    • Based on IEEE 802.16 (wireless broadband standards)

  • 3G (3^rd generation of mobile telecommunications tech)

    • Mobile data transfer standard

    • Mostly replaced at this point by 4G LTE

Describe the different methods of network security

Authentication is the process of verifying the identity of users accessing the wireless network, using methods like passwords, digital certificates, or biometric authentication. It can involve 1FA, 2FA, or 3FA.A firewall is a security device that monitors and controls network traffic, blocking unauthorized access, preventing malware attacks, and protecting sensitive data. It can be hardware, software, or a hybrid.A MAC (Media Access Control) address is a hard-coded address assigned to devices by manufacturers, used to identify specific hardware. Devices can be blocked or allowed based on their MAC addresses.Physical security protects hardware and network components from threats like theft, fire, or natural disasters. Measures include locked doors, access control (biometrics), off-site backups, and CCTV.Methods include encryption, UserIDs, passwords, PSK (pre-shared keys), WEP (Wired Equivalent Privacy), and WPA2 (Wi-Fi Protected Access 2)

Evaluate the advantages and disadvantages of each method of network security

User IDs allow for setting access rights for each user and creating user groups to manage rights in batches.User IDs can be stolen, systems can be bypassed, and they do not protect against intercepting messages or insider attacks.Encryption is very hard to break, and computers are fast enough to decrypt in real time.Users may use easy-to-guess passwords, the password must be transmitted over the network, and some encryptions have built-in backdoors.