A protocol is a set of rules and standards for doing something which have been agreed on. These protocols are used to allow different devices to be compatible. The most widely accepted set of protocols for data transmission is called TCP/IP. It stands for Transmission Control Protocol/Internet Protocol. It is a de facto standard for data transmission over the internet.
When you send a file it is broken into packets of data. Each packet is given a header which contains:
Packets that make up one bit of data, from one location may be sent in different routes depending on the data traffic conditions and availability of routes. This process makes sending information much more reliable and faster as packets take the quickest route to reach their destination. This is because other routes may be congested or down.
IP address (Internet Protocol): It is a 32-bit number for each device which allows data to be sent to and from it. There are static addresses which don’t change and dynamic addresses which do change, so the IP is not always the same. It is an unique identifier for each node in network. The internet uses TCP/IP to transmit data.
MAC (Media Access Control): Each network interface card has a unique static MAC address stored on it’s ROM. It allows devices on a network to be identified and enables compatibility between them if they follow this same protocol. It is a 48-bit number.