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Internet Protocol (IP)

Last Edit: 10/01/17

The Internet Protocol (IP) is a communications protocol and is a protocol within the Internet protocol suite; also referred to as TCP/IP. The Internet protocol suite has four abstraction layers and the Internet Protocol (IP) is within the Internet layer. The Internet Protocol (IP) was created in the 1970's when TCP/IP was being developed by DARPA. The Internet Protocol (IP) was invented by two individuals: Bob Kahn and Vint Cerf. The Internet Protocol (IP), as the name would suggest, is a core protocol of the Internet protocol suite, and perhaps the most important and vital of any protocol.

The Internet Protocol (IP) creates a numbering system for computer networks. Every device that connects to an IP network is assigned a number, and this number ensures that a device connected to a network can be identified, This, in effect, is somewhat like a telephone number, creating a unique number for the location of a physical device (telephone). The result is that the Internet Protocol (IP) creates an address system for devices that connect to IP networks like the Internet.

The Internet uses data packets for communication between host computers. Data packets are small blocks of data. The Internet Protocol (IP) dictates the structure of data packets on IP networks, and formats data packets with a header: the header includes an IP address for the destination device, and includes routing instructions for the physical devices (routers) that will deliver the packet Therefore, the Internet Protocol (IP) has developed a numbering system for IP networks, and also formats data so that it can be sent between these networks.

The Internet Protocol (IP) is described as an unreliable protocol: meaning that it only promises a 'best effort delivery' method. The Internet Protocol (IP) is referred to as datagram service: within a datagram transmission each data packet is treated as a separate entity: therefore, each data packet can be sent along a different route, which can result in the data being sent out of order, and, hence, IP is an unreliable protocol.

While the Internet Protocol (IP) enables IP networks to interconnect: it does not monitor or track performance, and passes responsibility for data transmission to the host computers of the Internet. Through a method of encapsulate, other Internet protocols - like TCP - enable hosts to reliable send and receive data.


A working version of the Internet Protocol (IP) was developed in the 1970's: BBN technologies, Stanford University and University College London (UCL) were the three organisations who were contracted by DARPA to develop a working version. This process lasted from 1975 to 1983, and resulted in the following protocols versions being created:

  1. Transmission Control Program Version 1 (TCP v1)
  2. Transmission Control Program Version 2 (TCP v2)
  3. Transmission Control Program Version 3 (TCP v3)
  4. Internet Protocol Version 3 (IP v3)

The final working version of the Internet Protocol (IP) was version 4: IPv4. Version 4 of the Internet Protocol (IP) is still in use today, and defines a 32bit number. The problem with IPv4 is that, during the 1990's, the amount of devices connecting to the Internet expanded exponentially. Simple put, IPv4 ran out of numbers it could assign. Therefore, version 6 of the Internet Protocol (IP) was developed in the 1990's and was released in 1998. IPv6 defined a 128bit number and is currently used on the Internet. It is established that in 2014 95% of all Internet traffic used IPv6.