Question 1
(1a) The following are three terms used in data communication. For each term, (1) explain its meaning or functionality; (2) state the name of the OSI reference layer it belongs to; and (3) appraise the function of its OSI reference layer.
(i) Amplitude modulation
(ii) Subnet
(iii) Media access control
(1b) The following are three pairs of concepts used in data communication. For each pair of concepts, apply these concepts in real-time video streaming in Internet (such as Youtube) and appraise their differences.
(i) "Error concealment" and "Error resilient"
(ii) "Network delay" and "Network jitter"
(iii) "Shortest path routing" and "Flooding"
Question 2
(2a) Plan communication channel to transmit a Word document. This document has a size of 2,300,750 Bytes, and the signal level is considered as 2 since it needs binary representation to store the Word document information
(i) Consider a noiseless communication channel A with a bandwidth 384 KHz, appraise the data transmission rate that can be achieved in this communication channel A.
(ii) Consider a noisy communication channel B with a bandwidth 5 MHz and a signal-to-noise ratio 42 dB. Analyse how many minutes are needed to transmit 100 copies of this document.
(iii) Appraise how to apply the error detection code method to handle the noise during image transmission via the communication channel B.
(iv) Appraise how to apply the buffering method to reduce the jitter of the communication channel B.
(2b) A modem constellation pattern has five data points (denoted as (x,y)) at the following positions: (0, 2), (2, 2), (-1, -3), (1.5, -0.5), (0,
1). Answer the following three questions.
(i) Determine the data point that has the largest distance to the centre, and determine the data point that has the largest angle.
(ii) Name the modulation method(s) used in this constellation pattern. Justify your answer.
(iii) Implement the amplitude modulation technique only to modify this constellation pattern, without changing the number of data points.
That means there are five data points in your modified constellation pattern. Provide the coordinates of the data points in the modified constellation pattern.
Question 3
(3a) Consider a network topology illustrated in Figure Q3(a), where the numbers on the graph edges represent the transmission bandwidth (in terms of Mbps) of data transmission. For example, the transmission bandwidth from the node A to the node B is 2 Mbps.
Figure Q3(a) A Network Topology.
(i) Apply the shortest path routing algorithm to diagram the best path from the source A to the destination F.
(ii) Describe the QoS factor "network delay", and appraise how to reduce network delay performance from the source A to the destination C.
(3b) Plan an IPv4 network for two banks A and B using consecutive IPv4 addresses. The bank B's IP addresses is larger than that of the bank A. These two banks A and B request 8192 and 2048 IP addresses, respectively. The ending IP address of the bank A is 218.66.31.255.
(i) Determine the IP address ranges of the bank A.
(ii) Determine the IP address ranges of the bank B.
(iii) Determine the subnet mask for bank A. Provide binary representation, decimal representation, and w.x.y.z/s notation.
(iv) Determine the subnet mask for bank B. Provide binary representation, decimal representation, and w.x.y.z/s notation.