In the late 70's another protocol came to be, that raised competition for TCP/IP. This protocol was known as Open System Interconnect (OSI). The International Standards Organization (ISO) developed OSI. The job of the ISO is to set standards for networking, character sets, database access and much more. The main goal of the ISO was to make OSI the standard protocol for worldwide internetworking. The US government became interested in OSI and they stated that US government organizations would be connected by OSI instead of TCP/IP. This resulted in Government Open Systems Interconnect Profile (GOSIP). The final result was that a special organization stated that they recommend that GOSIP be used in concurrence with TCP/IP. The OSI protocols never became fully functional as a result of the recommendation but in the end this was good for TCP/IP and the Internet. This meant that TCP/IP had a head start against the OSI protocols.
It also meant that TCP/IP was less complicated. OSI soon met its demise because the process took too long to release the full capabilities of OSI and now, compared to TCP/IP it is in miniscule amounts of production as.
In order for each layer of the model to communicate with the levels above and below it, certain rules were developed. These rules are called Protocols, and each protocol provides a specific layer of the model with a specific set of tasks or services. Each layer of the model has its own set of protocols associated with it. When you have a set of protocols that create a complete OSI model, it is called a Protocol Stack. An example of a protocol stack is TCP/IP, the standard for communication over the internet, or AppleTalk for Macintosh computers.
Protocols specifically work with ONLY the layer above and below...