T171 ECA - Significant Technology - TCP/IP
What Is TCP/IP?
TCP/IP (Transmission Control Protocol/Internet Protocol) is the basic form of communication on the Internet. It is a communication language or protocol used on packet-switched networks and can also be used on private networks such as intranets. With direct access to the Internet the computer has a copy of TCP/IP running so will any other computer connected to the Net.
TCP/IP is really two protocols that have been merged into one standard. TCP (Transmission Control Protocol) is the higher of the two layers and its job is to manage the break up of messages into smaller packets for onward transmission over the Internet. At the receiving computer TCP reassembles the packets back into the original message. TCP can also request resends of corrupt or missing packets.
The IP (Internet Protocol) is the lower layer and handles the addressing of each packet so that it goes to the correct destination. Each gateway computer on the network checks the IP address to see where to forward the packet. Packets of the same message may arrive at the destination computer via different routes, the message is reassembled from the packets at the destination.
[1]
The History of TCP/IP
In
1973 Vinton
Cerf and Bob
Kahn wanted to connect the APRANET with SATNET (satellite networking)
and packet radio. They realised that they need a link or "gateway"
to connect the network together in a way that would appear the same for
each network. They proposed to the International Network Working Group
on a "Protocol for Packet Network Inter-communication". This
new protocol was called the Transmission-Control Protocol (TCP). The TCP/IP
and gateway architecture was proposed in 1974. This protocol was independent
of the underlying network and computer hardware as well as having universal
connectivity throughout the network. This enabled any kind of platform
to participate in the network.
"In 1977 Cerf and Kahn demonstrated for the first time, the three networks system using the TCP protocol to send a packet from San Francisco Bay to London then back to University of Southern California, in the end the packet travelled over 150,400 Km with out loosing a bit (single binary number) "[2].
In 1978 Cerf, Postel and Danny Cohen decided to split TCP in to two separate functions of TCP and the Internet Protocol (IP). TCP monitors and ensures the correct transfer of data. IP, or Internet Protocol, receives the data from TCP, breaks it into packets and transmits it to a network within the Internet.
In 1981 a series of request for comment (RFC) was issued, standardising the TCP/IP version 4 for the APRANET. Within 12 months the TCP/IP protocol had succeeded in replacing NCP as the dominant protocol of the APRANET and was connecting to machines across the United States of America. Note: TCP protocol is described fully in RFC 793 and IP in RFC 791
"On January 1 1983 the APRANET and every network attached to the APRANET officially adopts the TCP/IP networking protocol, developed in the 1970s by pioneering network engineers Vinton Cerf and Bob Kahn. From then on, all networks that use TCP/IP are collectively known as the Internet. The standardization of TCP/IP allows the number of Internet sites and users to grow exponentially ".[3]
Over the years TCP/IP has handled most challenges by growing to meet the needs, and it is now the de-facto standard for internetworking for several reasons, including:
- a) it's simplicity and robustness when compared to alternatives such as OSI; b) it's availability on virtually every hardware and operating system platform; c) and it is the protocol suite on which the Internet depends.
The implementation of TCP/IP by the ARPANET and other networks allowed them to join together and form the world-wide network of networks now known as the Internet.
"Because the growing conglomerate of networks was able to communicate using TCP/IP protocols, the collection of networks gradually came to be called the Internet, borrowing the first word of Internet Protocol".[4]
Credits
- [1] Figure 1 from course material Chapter 2.6
- [2] History of the Internet TCP/IP - http://www.securenet.net/members/shartley/history/tcp_ip.htm - Visited 25-August-2001
- [3] History of the Internet - http://www.historyoftheinternet.com/chap4.html - Visited 17-Sep-2001
- [4] "Where Wizards Stay up Late" by Katie Hafner and Matthew Lyon - Book
Picture Sources
- Picture 1 - Vint Cerf from http://www.worldcom.com/generation_d/cerfs_up/index.phtml?grph=1 - downloaded 23-Sep-2001
- Picture 2 - Bob Kahn from http://www.cnri.reston.va.us/bios/kahn.html - downloaded 23-Sep-2001
Further Resources