Network Protocols
For devices to be able to communicate with each other they need to agree how that communication will take place for example who "speaks" first, what information they will send etc.
This is all sorted out by sets of rules. These rules are known as protocols. There are lots of protocols - the ones we are going to focus on are common network protocols.
The most important network protocol is the TCP / IP protocol (It is actually two protocols referred to as one). It controls how data is sent between two networks (eg over the internet) - without it the Internet would not be possible. Make sure you are comfortable with packets and packet switching otherwise this might get a bit confusing.
TCP (Transmission Control Protocol) - This sets the rules for how devices connect on the network. It splits data into packets (sending) and puts those packets back together again (receiving). It checks data is correctly sent and delivered (time out messages, receipt confirmation etc
IP (Internet Protocol) - This is responsible for packet switching (the routing of packets by the most efficient routes)
Ethernet Protocols - As data is typically transmitted over Ethernet cables, there is a set of rules for how this happens which are sometimes called ethernet protocols. Whether they are strictly protocols or not is debated but for GCSE Computer Science we use the term "Ethernet Protocol".
There is also a set of communication protocols that build upon the TCP / IP protocol and are transmitted over the internt too - see table below. (This building upon other protocols is known as the layer model - click here to learn more) :
Protocol | What it is used for |
HTTP - HyperText Transfer Protocol | Used by web browsers (Edge, Chrome etc) to access websites and communicate web servers |
| HTTPS - HTTP Secure | Same as HTTP except it encrypts all the data being sent and received (so it is more secure) |
| FTP - File Transfer Protocol | Used to access, edit, and move files beween devices for example opening files on a server from a client machine |
| POP3 - Post Office Protocol (V3) | Used to download (retrieve) emails from a server. When you use this protocol the email is deleted from the server and only exists where it was downloaded to. Can be a problem if you use 2 devices for checking emails as it will only be on one |
| IMAP - Internet Message Access Protocol | Used to get a copy of (retrieve) emails from a server. The server keeps a copy and the accessing devices gets a copy too. You have to deliberately delete the email to get rid of it from the server. Better for accessing from 2 or more devices. |
| SMTP - Simple Mail Transfer Protocol | Used to send emails, and transfer them between servers. |