payload and the size of the UDP datagram is large enough to hold any chunk of

Payload and the size of the udp datagram is large

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payload, and the size of the UDP datagram is large enough to hold any chunk of multimedia data as defined so far. b. TCP is not an appropriate protocol for multicasting and multi-party com- munication because it is a connection-oriented protocol in which a connec- tion involves only two parties. UDP, on the other hand, is a connection-less protocol. Multicasting and multi-party communication can be achieved using UDP. Using the same multicast address, a UDP sender can send mul- ticast packets to many receivers; several UDP senders can use the same multicast addresses to create multi-party communication. c. TCP delivers data bytes to the application program in order. This means that if a segment is missing, the out-of-order bytes need to wait. This is not appropriate for live or real-time interactive multimedia streaming, as dis- cussed in the text. This problem does not exist in UDP. Each UDP packet is 1000 0110 0 000 0011 0010 0001 0011 0010
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9 independent, and the chunk of data carried in a UDP datagram can be delivered to the application program as it arrives. d. Since multimedia chunks can use different encoding methods, we need a field to define the type of payload. A TCP segment lacks this field. A UDP datagram can allow encapsulation of the RTP packet, which includes this field. e. For a live or real-time multimedia streaming, there is a need for synchroni- zation using timestamps that define the temporal relationship between each chunk and the other chunks. None of the three protocols, TCP, UDP, or SCTP, provide timestamping. UDP, however, allows the encapsulation of the RTP packets, which includes timestamping. Since an SCTP packet can carry many data chunks in a single packet, timestamping may not be needed if the stream is short. f. Congestion control in multimedia communication is a big issue because of the volume of data exchanged. Although TCP has a congestion control mechanism, it is not suitable for multimedia communication, because it is based on segments, not chunks. Congestion control in UDP/RTP is more convenient for multimedia communication. P8-33. We answer each question below: a. The following shows the time lines and the contents of the priority queue (Q1) and non-priority queue (Q2). Arrival Processing Departure t 1 t 0 t 2 t 3 t 4 t 5 t 6 t 7 t 8 t 9 t 10 t 11 t 12 t 13 t 14 t 15 t 16 t 1 t 0 t 2 t 3 t 4 t 5 t 6 t 7 t 8 t 9 t 10 t 11 t 12 t 13 t 14 t 15 t 16 1 1 2 4 5 6 7 8 9 10 3 2 3 4 5 6 7 8 9 10 10 10 10 10 10 10 1 2 3 4 5 6 8 10 7 9 Q1 Q2 t 0 Q1 Q2 t 1 Q1 Q2 t 2 Q1 Q2 t 3 Q1 Q2 t 4 Q1 Q2 t 5 Q1 Q2 t 6 Q1 Q2 t 7 Q1 Q2 t 8 Q1 Q2 t 9 Q1 Q2 t 10 Q1 Q2 t 11 Q1 Q2 t 12 Q1 Q2 t 13 Q1 Q2 t 14 Q1 Q2 t 15 2 3 3 4 4 4 5 5 5 5 5 5 5 5 6 6 6 6 6 6 6 6 7 7 8 8 8 8 8 8 8 9 9
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10 b. For the packets in the priority class, we find the time spent in the router for each class, which is the departure time minus the arrival time. We also find the relative departure delay, as shown below. Since the relative delays are the same for each packet, the router does not create jitter in this class.
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