http://www.flyfish.com/rods/brand_name.html
http:// protocol prefix (most browsers default to HTTP if a prefix is not typed)
www.fiyfish.com/ domain name
equipment/ subdirectory name
rods/ Subdirectory name
brand_name.html document name (webWeb page)
IP Address. Every computer node and host attached to the Internet must have a unique Internet protocol (IP) address. For a message to be sent, the IP addresses of both the sending and the recipient nodes must be provided. Currently, IP addresses are represented by a 32-bit data packet. The general format is four sets of numbers separated by periods. The decomposition of the code into its component parts varies depending on the class to which it is assigned. Class A, class B, and class C coding schemes are used for large, medium, and small networks, respectively. To illustrate the coding technique, the IP address 128.180.94.109 translates into:
128.180 Lehigh University
94 Business Department faculty server
109 A faculty member’s office computer (node)
Protocols
The word protocol has been used several times in this section. Let’s now take a closer look at the meaning of this term. Protocols are the rules and standards governing the design of hardware and software that permit users of networks, which different vendors have manufactured, to communicate and share data. The general acceptance of protocols within the network community provides both standards and economic incentives for the manufacturers of hardware and software. Products that do not comply with prevailing protocols will have little value to prospective customers.
The data communications industry borrowed the term protocol from the diplomatic community. Diplomatic protocols define the rules by which the representatives of nations communicate and collaborate during social and official functions. These formal rules of conduct are intended to avoid international problems that could arise through the misinterpretation of ambiguous signals passed between diplomatic counterparts. The greatest potential for error naturally exists between nations with vastly dissimilar cultures and conventions for behavior. Establishing a standard of conduct through protocols, which all members of the diplomatic community understand and practice, minimizes the risk of miscommunications between nations of different cultures.
An analogy may be drawn to data communications. A communications network is a community of computer users who also must establish and maintain unambiguous lines of communication. If all network members had homogeneous needs and operated identical systems, this would not be much of a problem; however, networks are characterized by heterogeneous systems components. Typically, network users employ hardware devices (PC, printers, monitors, data storage devices, modems, and so on) and software (user applications, network control programs, and operating systems) that a variety of vendors produce. Passing messages effectively from device to device in such a multivendor environment requires ground rules or protocols.
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What Functions Do Protocols Perform?
Protocols serve network functions in several ways. First, they facilitate the physical connection between the network devices. Through protocols, devices are able to identify themselves to other devices as legitimate network entities and initiate (or terminate) communications session.
Second, protocols synchronize the transfer of data between physical devices. This involves defining the rules for initiation a message, determining the data transfer rate between devices, and acknowledging message receipt.
Third, protocols provide a basis for error checking and measuring network performance. This is done by comparing measured results against expectations. For example, performance measures pertaining to storage device access times, data transmission rates, and modulation frequencies are critical to controlling the network’s function. Thus, the identification and correction of errors depends on protocol standards that define acceptable performance.
Fourth, protocols promote compatibility among network devices. To transmit and receive data successfully, the various devices involved in a particular session must conform to a mutually acceptable mode of operation, such as synchronous, asynchronous and duplex, or half-duplex. Without protocols to provide such conformity,