The goals of this homework are to develop an understanding a communications model, data communications, networks, protocol architecture as well as the basic concepts of data transmissions, data rate, bandwidth and channel capacity.
1. (10 points) Briefly explain the advantages and disadvantages of using layered architecture in computer networks.
2. (10 points) What tasks are performed by the data link layer and the transport layer?
3. (10 points) Draw (by hand) the spectrum of the signal s(t) = 4sin(2pt) + 2sin(6pt) +
). Also identify the absolute and effective bandwidths.
4. (10 points) What is the channel capacity for a teleprinter channel with a 300-Hz bandwidth and a signal-to-noise ratio of 3 dB, where the noise is a white thermal noise?
5. (10 points) A digital signaling system is required to operate at 9600 bps. If the signal encodes a 4-bit word, what is the minimum required bandwidth of that channel?