In this problem, we explore the use of small packets for Voice-over-IP applications.One

Chapter 5, Problem P27

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In this problem, we explore the use of small packets for Voice-over-IP applications.One of the drawbacks of a small packet size is that a large fraction oflink bandwidth is consumed by overhead bytes. To this end, suppose that thepacket consists of P bytes and 5 bytes of header.a. Consider sending a digitally encoded voice source directly. Suppose thesource is encoded at a constant rate of 128 kbps. Assume each packet isentirely filled before the source sends the packet into the network. Thetime required to fill a packet is the packetization delay. In terms of L,determine the packetization delay in milliseconds.b. Packetization delays greater than 20 msec can cause a noticeable andunpleasant echo. Determine the packetization delay for L = 1,500 bytes(roughly corresponding to a maximum-sized Ethernet packet) and forL = 50 (corresponding to an ATM packet).c. Calculate the store-and-forward delay at a single switch for a link rate ofR = 622 Mbps for L = 1,500 bytes, and for L = 50 bytes.d. Comment on the advantages of using a small packet size.