The Transmission Control Protocol/Internet Protocol (TCP/IP) suite are a set of standards that describe the functions necessary to send data over a network. They are designed to divide the responsibility for the various aspects of data transmission into categories.
Rather than write one protocol for each category, specialised protocols cover smaller aspects of each task. This means there are subgroups of protocols. These groupings are called "Layers," and the layers are represented as levels in a stack. Each layer uses services from the layer below and provides services to the layer above. This principle is called "abstraction."
International open standards enable different companies to write compatible software. When data travels over the Internet, both the sender and receiver have to speak the same language. The TCP/IP protocols provide a common set of procedures and codes everyone follows.
The membership of the TCP/IP protocol suite changes constantly. New protocols are added and others are adopted from other systems. The most influential protocol in the suite is the Internet Protocol. This defines the address formats for all devices contactable over the Internet, and is used by all networking systems communicating over the Internet.