3_Tutorial 1.docx

Tutorial (1) Line configurations (or types of connections) are point-to-point and multipoint In half-duplex transmission, only one entity can send at a time; in a full-duplex transmission, both entities can send at the same time. Data flow: The number of cables for each type of network is...

Tutorial (1) Line configurations (or types of connections) are point-to-point and multipoint In half-duplex transmission, only one entity can send at a time; in a full-duplex transmission, both entities can send at the same time. Data flow: The number of cables for each type of network is: Mesh: n (n – 1) / 2 Star: n Ring: n – 1 Bus: one backbone and n drop lines An internet is an interconnection of networks. The Internet is the name of a specific worldwide network Standards are needed to create and maintain an open and competitive market for manufacturers, to coordinate protocol rules, and thus guarantee compatibility of data communication technologies. Mesh topology: If one connection fails, the other connections will still be working. Star topology: The other devices will still be able to send data through the hub; there will be no access to the device which has the failed connection to the hub. Bus topology: All transmission stops if the failure is in the bus. If the drop-line fails, only the corresponding device cannot operate. Ring topology: The failed connection may disable the whole network unless it is a dual ring or there is a by-pass mechanism Frequency and period are the inverse of each other. T = 1/f and f = 1/T. Example 1 Example 2 Example 3 Using Fourier analysis. Fourier series gives the frequency domain of a periodic signal; Fourier analysis gives the frequency domain of a nonperiodic signal. The Nyquist theorem defines the maximum bit rate of a noiseless channel. Optical signals have very high frequencies. A high frequency means a short wave length because the wave length is inversely proportional to the frequency (λ = v/f), where v is the propagation speed in the media. The time-domain and frequency-domain plots of a sine wave: The time domain and frequency domain of three sine waves: