Task 2 – Communication Networks

a) Explain the difference between datagram and virtual circuit operation.

b) Differentiate between interactive data traffic and non-interactive data traffic with an appropriate example.

c) If the people are receiving poor quality video, what QoS requirements might not be being met?

d) The following parameters for a switching network will be used (see below for further details). For N = 4, L = 3000, B = 9600, P = 1080, H = 80, S = 0.2, T = 0.02, D = 0.001, compute the end-to-end delay for (i) circuit switching, (ii) virtual circuit packet switching, and (iii) datagram packet switching. Assume that there are no acknowledgements. Ignore processing delay at the nodes. Assume no header for circuit switching.

• N = number of hops between two given end systems

• L = message length in bits

• B = data rate, in bits per second (bps), on all links

• P = fixed packet size, in bits

• H = overhead (header) bits per packet

• S = call setup time (circuit switching or virtual circuit) in seconds

• T = call teardown time (circuit switching or virtual circuit) in seconds

• D = propagation delay per hop in seconds