Computer Networks - Case Study Example

of Assignment Synchronous and asynchronous Synchronous is defined as the kind of transmission, which involves a synchronization of an ordinary clock. In a synchronous mode data is typically transmitted in the form of blocks instead of transmitting individual characters. Asynchronous is defined as the type of transmission of data where individual characters are transmitted one by one. Each character is outlined by the use of a single bit at the start called “start bit” and another bit at the end called “stop bit”. Synchronous mode has greater data transmission speed as compared with the asynchronous mode because in asynchronous mode lots of bits are wasted in transmitting individual characters. Asynchronous mode is used only at that places where slow data transmission is required. Analog and Digital Analog is defined as the type of electronic transmission achieved by using varying or unstable frequency signals or simply those signal that vary across a constant scale. Analog signal technology is mostly used as transmission in phone and in radio transmissions. Digital means demonstrating the quantities in the form of discrete units. The information is stored and operated as a succession of discrete values. Using zeros create digital signals and ones on the other hand dips and linear bumps create analog singles. Digital devices are less expensive than analog devices. Digital devices are considered more precise than the analog and are usually replacing analog devices. For example at petrol pumps digital meters have replaced analog meters etc XON and XOFF XON and X0FF is basically a protocol to control the data flow between other devices and computers present on a connection. For example, in the case of a computer and printer, data sent by the computer is much faster then the printer to print it. The printer holds a buffer, which is used to store data to reduce the speed mismatch between the two devices. If the buffer memory becomes full then the printer processor sends XOFF signal to end sending more data. When the buffer memory frees up, the printer processor launches an XON signal to inform the computer to continue sending the data. XON signal is used to resume transmitting data whereas the XOFF signal is used to stop further transfer of data. Simplex and duplex Simplex-mode is one-way communication mode in which sender remains sender and receivers remains receiver. It is also known as one-way communication mode. For example radio transmission. Duplex means bi-directional. Duplex mode is also called two-way communication mode. There are two types of duplex-mode. Half duplex: In a half duplex mode both sender and receiver can send data on a connection but one at a time. When sender sends the data receiver waits and when receiver transmits data sender has to wait. For example Walky-talky Full duplex: In a full duplex mode both sender and receiver can send the data at the same time for example Telephone communication Simplex mode is mostly used in machine-based communication whereas the duplex mode is what we use in our daily lives. Serial and parallel transmission Serial transmission is defined as a scheme to transmit data in the form of bits over a single channel. It is also know as one at a time transmission. Parallel transmission is defined as transmitting groups of bits over multiple channels at the same time. Parallel transmission is several times faster than the serial transmission. Another main difference between the two types of transmissions is the cost factors. Parallel transmission needs more wires or line to transmit the data whereas serial transmission requires only two wires or channels. Parallel transmission is usually used for small distances whereas serial transmission can be used for longer distances. Base band and broadband Base band signals are low frequency signals that are retransmitted along the way. Broadband is phrase or word, which is used for a type of speedy Internet access. Broadband is intended to provide home users and business immediate Internet access for twenty-four hours. In the case of base band transmission, the whole bandwidth of the wire is devoted to a single signal whereas in the case of broadband transmission, signals are transmitted using several frequencies in order to allow various signals to be transmitted at the same time. So broadband is a type of telecommunication in which a vast range of frequencies can be used whereas in the case of base band single frequency is used at a time. Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP) SLIP or serial line Internet protocol is basically a TCPIP protocol, which is used for communication among various machines, which have been put together to communication with each other. PPP or Point-to-point protocol is defined as a rule to transmit various data grams of protocol to point-to-point links. PPP protocol is much more tough and flexible as compared with the SLIP. PPP is better-designed and newer protocol than SLIP. Another difference between SLIP and PPP is that PPP is multi-protocol transfer system. It means that PPP not only transports TCP/IP traffic, but can also transport IPX. Hypertext Transfer Protocol (HTTP) and File Transfer Protocol (FTP) Hyper Text Transfer Protocol (HTTP) is defined as a protocol, which is used in order to shift files to web browser from a Web server. As a result Web page becomes visible on the Internet. File Transfer protocol (FTP) is a protocol used in order to upload the files to FTP server from workstation. The main difference between FTP and HTTP is that in FTP, complete files are shifted from one machine to another machine and stored into memory whereas in HTTP web contents are transferred to a the web browser to view. FTP is known as two-way system because files can be shifted back and forth between workstation and server whereas HTTP is known as a one-way scheme because the files are transmitted from the server to web browser only. Transmission Control Protocol (TCP) and Internet Protocol (IP) The main difference between Transfer Control Protocol (TCP) and Internet protocol (IP) is that TCP is basically responsible for the safe delivery of data packets and IP maintains the logical addresses. The job of IP is to get the address and the job of TCP is to ensure the delivery of data to the address provided by the IP. These two protocols work side by side. Each is responsible to fulfill its own specific Job References Andrew S. Tanenbaum (2003). Computer Networks Prentice Hall PTR John L. Hennessy, David A. P, Andrea C. A. (2007). Computer Architecture: A Quantitative Approach Morgan Kaufmann Read More