1.5: Network Topologies, Protocols and Layers - YK Flashcards
What is a star network?
A network where all computers are connected to a central server or switch
What are the pros and cons of a star network?
Pros: network can be managed centrally, easy to add more computers, network still runs if one computer breaks
Cons: no computers will work if server breaks, needs specialist equipment (switch)
What is a mesh network?
Full mesh: every computer connected to every other computer, all computers equally important
Partial mesh: most computers connected to each other, all computers equally important
What are the pros and cons of a mesh network?
Pros: robust and reliable cabling method, not reliant on server (still works if any computer breaks)
Cons: requires lots of cabling (expensive)
What are WiFi frequencies and channels?
WiFi is a standard for connecting computers on a wireless network by sending data across radio waves
WiFi signals operate at different ranges of frequencies (of the radio waves) that are split into channels which can be different widths depending on the technology using them, changing to a different channel can reduce interference and improve performance
What is WiFi encryption?
To prevent the data from being accessed, WiFi signals are encrypted, the types (oldest-newest) are WEP, WPA, WPA2, WPA3
What is Ethernet?
A protocol that governs the transmission of data between devices using cables on a LAN, useful to connect nearby (<100m) devices (long distance - signal degrades), ethernet uses broadcast addressing so all devices receive every transmission then check if address is theirs, devices can only send data when no other devices are transmitting to avoid data collision so Ethernet system uses collision detection
What are IP and MAC addresses?
IP address is a unique identifying number given to everything connected to the internet which determines where data is sent to/from
MAC address is a unique number hard wired into every piece of networking equipment (doesn’t change)
What do the following protocols do?
TCP/IP, HTTP, HTTPS, FTP, POP, IMAP, SMTP
Transmission Control Protocol/Internet Protocol: for sending any data across internet
Hyper Text Transfer Protocol: for sending + receiving data about web pages
Hyper Text Transfer Protocol Secure: for sending + receiving encrypted data about web pages
File Transfer Protocol: for sending files
Post Office Protocol: for receiving emails
Instant Message Access Protocol: for receiving emails and syncing emails to the server
Simple Mail Transfer Protocol: for sending emails
What is a protocol?
Protocols establish how two computers send and receive a message
What are protocol layers?
Protocols aren’t just one process, so they are broken down into layers each with a different function (functions combined complete task of sending data)
Each protocol is different but an overarching model (OSI model) tries to show all the possible layers: application, presentation, session, transport, network, data link, physical
What is packet switching?
Data is split into packets (chunks of data); each packet is marked with sending + receiving IP address, sending + receiving MAC address, how many total packets, which numbered packet this one is; packets can take any route across internet; packets reassembled at the other end into original full message; if a packet is lost it can be requested again
