Computing Protocol

Report Plan

A protocol can also be described as a set of rules or instructions. Protocols may be implemented by hardware, software, or a combination of the two. At the lowest level, a protocol defines the behavior of a hardware connection. The Advanced Research Projects Agency Network (ARPANET) developed by ARPA of the United States Department of Defense was the world's first operational packet switching network, and the predecessor of the global Internet. Packet switching, now the dominant basis for both data and voice communication worldwide, was a new and important concept in data communications. The precursor to the Internet, ARPANET was a large wide-area network created by the United States Defense Advanced Research Project Agency (ARPA). Established in 1969, ARPANET served as a testbed for new networking technologies, linking many universities and research centers. The first two nodes that formed the ARPANET were UCLA and the Stanford Research Institute, followed shortly thereafter by the University of Utah.

Part 1: Web Report

In computing, a protocol is a convention or standard that controls or enables the connection, communication, and data transfer between two computing endpoints. In its simplest form, a protocol can be defined as the rules governing the syntax, semantics, and synchronization of communication. A protocol can also be described as a set of rules or instructions. Protocols may be implemented by hardware, software, or a combination of the two. At the lowest level, a protocol defines the behavior of a hardware connection. The widespread use and expansion of communications protocols is both a prerequisite to the Internet, and a major contributor to its power and success. The pair of Internet Protocol (or IP) and Transmission Control Protocol (or TCP) are the most important of these, and the term TCP/IP refers to a collection (or protocol suite) of its most used protocols. Most of the Internet's communication protocols are described in the RFC documents of the Internet Engineering Task Force (or IETF). Object-oriented programming has extended the use of the term to include the programming protocols available for connections and communication between objects. Generally, only the simplest protocols are used alone. Most protocols, especially in the context of communications or networking, are layered together into protocol stacks where the various tasks listed above are divided among different protocols in the stack. Whereas the protocol stack denotes a specific combination of protocols that work together, the Reference Model is a software architecture that lists each layer and the services each should offer. The classic seven-layer reference model is the OSI model, which is used for conceptualizing protocol stacks and peer entities. This reference model also provides an opportunity to teach more general software engineering concepts like hiding, modularity, and delegation of tasks. This model has endured in spite of the demise of many of its protocols (and protocol stacks) originally sanctioned by the ISO. The OSI model is not the only reference model however.

The Advanced Research Projects Agency Network (ARPANET) developed by ARPA of the United States Department of Defense was the world's first operational packet switching network, and the predecessor of the global Internet. Packet switching, now the dominant basis for both data and voice communication worldwide, was a new and important concept in data communications. Previously, data communications was based on the idea of circuit switching, as in the old typical telephone circuit, where a dedicated circuit is tied up for the duration of the call and communication is only possible with the single party on the other end of the circuit. With packet switching, a system could use one communication link to communicate with more than one machine by assembling data into packets. Not only could the link be shared (much as a single mail person can be used to post letters to different destinations), but each packet could be routed independently of other packets. This was a major advancement. The starting point for host-to-host communication on the ARPANET was the 1822 protocol which defined the way that a host sent messages to an ARPANET IMP. The message format was designed to work unambiguously with a broad range of computer architectures. Essentially, an 1822 message consisted of a message type, a numeric host address, and a data field. To send a data message to another host, the sending host would format a data message containing the destination host's address and the data to be sent, and transmit the message through the 1822 hardware interface. The IMP would see that the message was delivered to its destination, either by delivering it to a locally connected host or by delivering it to another IMP. When the message was ultimately delivered to the destination host, the IMP would send an acknowledgment message (called Ready for Next Message or RFNM) to the sending host. Unlike modern Internet datagrams, the ARPANET was designed to transmit all 1822 messages reliably, or at least to be able to tell the host when a message was lost. Nonetheless, the 1822 protocol did not prove to be adequate by itself for juggling multiple connections between different applications residing on a single host. This problem was addressed with the Network Control Program or NCP, which provided a standard method to establish reliable, flow-controlled, bidirectional communications links between different processes on different hosts. The NCP interface allowed application software to connect across the ARPANET implementing higher-level communication protocols. This was an early example of the protocol layering concept incorporated into the OSI model. In 1983, TCP/IP protocols replaced NCP as the principal protocol of the ARPANET, and the ARPANET became just one component of the fledgling Internet. After the ARPANET had been up and running for several years, ARPA looked for another agency to hand off the network to; ARPA's primary business was funding cutting-edge research and development, not running a communications utility. Eventually, in July 1975, the network was turned over to the Defense Communications Agency, also part of the Department of Defense. The ARPANET was designed in the 1960s for the US Defense Department, so as to develop new bombproof, distributed packet-switching network technology. It got its name from the provider of the funds, the Advanced Research Projects Agency (ARPA). In the autumn of 1969 the first ARPANET computer was connected to the ARPANET's IMP node at the University of California at Los Angeles (UCLA). Doug Engelbart's hypertext-project computer at Stanford Research Institute (SRI) was the next. By the end of the year, the network also included the computers at the

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