The TCP/IP model is a description framework for computer network protocols created in the 1970s by DARPA, an agency of the United States Department of Defense.TCP/IP is the short form of transmission control protocol and Internet protocol.
Tcp/ip is the basic communication language or protocol of the Internet, nowadays. It can also be used as a communications protocol in a private network (either an intranet or an extranet, VPN). When you access Internet, your computer is provided with a copy of the TCP/IP program just as every other computer that you may send messages to or get information from also has a copy of TCP/IP. The TCP/IP Model is just another model ,which replaced OSI (because of various drawbacks and lack of protocols).
There are 4 layers of TCP/IP , which are divided into two groups.
- Transmission protocol- It the higher layer, that manages the assembling of a message or file into smaller packets that are transmitted over the Internet and received by a TCP layer that reassembles the packets into the original message.
- Internet protocol -Its the lower layer, that handles the address part of each packet so that it gets to the right destination.
The following shows the different layers of TCP/IP Model
OSI, Open Systems Interconnection model ,is open standard for communication among two systems. OSI model was developed " Charles Bachman " which evolved to remove various difficulty faced in ARPANET. If you are interested ,the actual document is available free of cost at
TU-T/X.200-series of recommendations
or
http://www.itu.int/rec/T-REC-X.Imp200-200612-I/en
The Open System Interconnection (OSI) model is a set of protocols that attempt to define and standardize the data communications process. Its divides the communication channel into 7 layers ,each layer performing its own functionality. Numerous protocols at each layer provide security and encapsulation . each layer is at the top of another and transfer data to each other from SAP ( service access protocol)
The figure below show us the 7 layers of OSI
As in the figure the last three layers are grouped as "Media layers" and the upper four as "Host Layers". Media layers are mainly responsible for transferring the data through the physical medium ( converting the data into bit streams , synchronizing it, etc) where as the host layer is mainly focused on how the data is to be represented and various applications interfaces.
NOTE: Segment and Presentation Layers are usually not very useful and hence were removed in TCP/IP MODEl.
hope u understood and Best of Luck.
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