IP – Internet protocol
This is the basic layer of the protocols. Almost all communication in the internet network is implemented using this protocol. This is the address (numeric labels) of all the devices connected to the computer network. IP addresses can be either public or private. There are two versions of IP addresses IPv4 and IPv6. All other protocols (TCP, UDP etc) are built top of IP.
Messages over IP are communicated as packets, which are small bundle of information at 2^16 bytes. Each packet will have a Header and Data part. Header will have all the meta data about the packets and data