Networking Protocols

Communication requires protocols (rules) so that those involved in the communication understand how to interact. In the world of technology this could be communication between two or more computers which means for example they may need to understand:

Transmission speed
Type of data to be shared
How to share the data

Protocols for use over the Internet are generally published as RFCs (Request for Comments) by standards setting bodies such as the Internet Engineering Task Force (IETF).

TCP and UDP

Transmission Control Protocol (TCP) and User Datagram Protocol are communication protocols used to share data across a network such as the Internet.

TCP is connection oriented, it involves sender and receiver going through a handshake process and has error checking/error correction.

UDP is connectionless, it does not involve a handshake and does not have error correction (i.e. no guarantee of delivery. However, it is faster than TCP.

Example Protocols

There are many different types of protocols used over TCP and UDP. These include, but are not limited to:

Protocol	Description	Port
HTTP	Hyper Text Transfer Protocol Used for communication between web servers and clients	80
HTTPS	Hyper Text Transfer Protocol Secure Same as above but uses secure encryption	443
FTP	File Transfer Protocol Used to transfer files	21
SFTP	Secure File Transfer Protocol or SSH File Transfer Protocol Same as above but uses secure encryption	22
SSH	Secure Shell Allows for remote connection / remote command execution	22
NTP	Network Time Protocol An NTP server provides time services to a client.	123
SMTP	Simple Mail Transfer Protocol Used to send and receive emails	25
POP3	Post Office Protocol version 3 Used by a client to download emails from a server	110
IMAP	Internet Message Access Protocol Unlike POP3 it can be used by multiple clients and generally leaves the emails on the server	143

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