1.3.2 - Wired and wireless networks, protocols and layers

• Fast and consistent transmission speed • Costly to add extra devices as additional cabling and switches may be required. • Copper cable may be susceptible to electrical or magnetic interference whereas fibre optic cabling avoids this. • Ethernet cabling maintains a good signal strength up to 100m and fibre optic can be much longer. • Data sent along cables cannot be easily intercepted, therefore higher security.

• Fast and consistent transmission speed • Data sent along cables cannot be easily intercepted, therefore higher security.

• Costly to add extra devices as additional cabling and switches may be required.

• Typically slower than cabled connections. • Easy to connect additional devices, however will share available bandwidth and increase traffic. • Wireless signals can be reduced by walls from other wireless device interference, which affects the speed of connection. • Wireless hotspots a limited to very small local areas and require repeater devices to expand the range. • Wi-Fi signals may be easily intercepted without encryption security. • (+) It is a portable connection, therefore ideal/convenient. • devices can move around whilst connected, not fixed to one spot, allowing people to use them from where needed. • (+) reduced risk of trailing wires and trip hazards • (+) more devices can connect because suitable ports are not necessary, so wider range of devices can connect.

benefits of wireless (markscheme): * Allows more devices to connect … * …for example televisions, mobile phones * Easy to connect (devices) // Easier to setup (wireless connections) // By example e.g. easier for guests to connect their devices * Home is likely small area * … so short distance wireless is sufficient * Devices can move around // can use devices in different areas // can connect from anywhere in the house // can use where wires don’t reach // can access from a larger area (than wired) * … by example e.g. student is using a laptop so does not need to be tied to one place // by example e.g. they don’t have to disconnect before moving // e.g. they can stay connected whilst moving * Cheaper to purchase/install/setup for new devices // no cost for (new/replacement) wires/hardware * …because no additional/fewer wires are needed * Fewer trip hazards from trailing wires // reduce risk of damage to cables // fewer cables to damage * More compatible // some devices only have wireless connections more bits: - (+) It is a portable connection, therefore ideal/convenient. - devices can move around whilst connected, not fixed to one spot, allowing people to use them from where needed. - (+) reduced risk of trailing wires and trip hazards - (+) more devices can connect because suitable ports are not necessary, so wider range of devices can connect.

mark scheme bits: * Prone to interference // by example * Limited range of signal * Slower rate of transmission // less bandwidth // reduced network performance// increased latency // BOD slower connection // more users reduces rate of transmission / bandwidth /performance etc. * Increased risk of security concerns // by example e.g. A hacker could connect to the wireless connection * Less stable connection * Higher chance of collisions // Higher error rate

• network cabling includes coaxial copper cable, twisted pair (copper) Ethernet cable and fibre optic cabling. • Copper wire cables are cheaper, but have some disadvantages with fibre optic cabling overcomes. • Fibre optic cable transmits data as pulses of light through a single strand of glass fibre, which can transmit large amounts of data over long distances without interferences. • Ethernet is a standard commonly used for communicating of a WAN, which provides error-free and reliable communication between two points. Governs how data is sent and received.

• Wi-Fi uses radio waves to transmit data. • As long as a device has a wireless NIC, it can connect to a wireless network. • 100m range with high bandwidth. • Bluetooth is a radio wave technology commonly used to connect devices within a 10 metre location of one another. Common uses include hands-free speakers and smartwatches. • Low bandwidth

• An IP address is a unique public address for the router of a network. • Used to route data packets across networks, after which they are directed towards a private IP address, which is not unique, and will change when the device moves from one network to another. • There are two types of IP version addresses (IPv4 and IPv6).

• IPv4 is a 32 bit address, written as four numbers, separated by (.) with each number between 0-255. • an example of an IPv4: 69.89.31.212 • IPv6 are replacing IPv4 as addresses are running out. They are an 128 bit address, written as 8 groups separated by (:) with each group making up four hex values, representing 16 bits. • an example of IPv6: 2001:0db8:85a3:0000:0000:8a2e:0370:7334

• A MAC address is a unique hexadecimal number assigned to every NIC used in any device. The MAC address of a device will NEVER change. • Made up of 12 hexadecimal digits. • an example of a MAC address: 30:0a:95:9d:68:16

• Standards allow hardware and software to interact across different manufacturers or producers. • Standards provide rules for different areas eg. cabling, Ethernet, connectivity. • A Network Standard specifies the way that computers access a network, as a set of guidelines so that they can work together (compatibility). • eg. HTML would be a computer standard for creating websites and allowing them to be viewed on the World Wide Web. • eg. USB is a standard that defines the type of connector used to connect peripheral devices to computers. • eg. Ethernet is a standard that provides a universally accepted set of rules, protocols and cabling specifications that always networking of hardware etc.

• Ethernet is used by (mostly) all manufacturers // Ethernet is used in many devices • To allow compatibility with other devices • Ethernet has a high bandwidth • Ethernet has inbuilt security • Ethernet is a proven/reliable connection • Ethernet is low cost for purchase/installation/maintenance (compared to other wired connections)

• A protocol is a set of rules. • A network protocol defines the standards for data transmission.

• Transmission Control Protocol/Internet Protocol • Communicate over LAN’s and WAN’s. • TCP provides an error free transmission between two routers. • IP routes packets across WAN’s. • Together they make up the TCP/IP protocol stack which is the foundation of communication across the Internet.

• Hypertext Transfer Protocol • Used by a browser to access a webpage from a web server per requests • (+) HTTP is a way for a client and server to send and receive request, and deliver HTML web pages. • (+) It is a fundamental protocol of World Wide Web (WWW)

• Hypertext Transfer Protocol Secure • Webpage requests • Same purpose as HTTP except it adds encryption and authentication. • It should be used on the web, when a website deals with sensitive information, such as passwords or bank details etc. To keep the information secure and safe.

• File Transfer Protocol • FTP is used for sending and transmitting files between computers, normally on a WAN. • Used to upload and download files from a server • (+) Often people use FTP clients, which are software applications on top of the FTP protocol, a user will interact with the client program, and it generates and sends the appropriate FTP commands.

• Post Office Protocol • POP3 retrieves emails from a mail server. It removes the original copy from the mail server when retrieved by the client and is transferred to your device.

• Internet Message Access Protocol • IMAP keeps emails on the mail server, which allows synchronicity between all devices.

• Simple Mail Transfer Protocol • SMTP transfers outgoing emails from one server to another, from an email client to a server. • Used for sending only.

The concept of layering is to divide the complex task of networking into smaller, simpler tasks that work with each other.

• Reduces the complexity of the problem into manageable sub-problems. • Devices can be manufactured to operate at a particular layer. • Products from different vendors will work together. mark scheme (why protocols have layers): * Each layer is independent // layers are not reliant on other layers * One layer can be changed without affecting the others // a layer can function without needing/changing/impacting any other layer // self-contained * Separates tasks so they can be developed independently * A developer can focus on only one layer // developer can specialise * Allows for standards for individual tasks/layers to be developed // for compatibility * Manufacturers can develop hardware to fit into one particular layer * To group together similar protocols