Computer Network
Q: Consider sending over HTTP a Web page that consists of one video clip, and five images. Suppose that the video clip is transported as 25 frames, and each image has 4 frames.
- If all the video frames are sent first without interleaving, how many “frame times” are needed until all five images are sent?
b. If frames are interleaved, how many frame times are needed until all five images are sent.
Q: Consider sending 6 Kbyte from host A to host B using Stop and Wait, Go-Back-N, and Selective Repeat. Assume packet size (L) is 2 Kbyte, data rate (R) is 8Mbps, RTT = 18ms, window size (W) is 4 packets, and the Timeout = 30 ms.
Case 1: Assume all packets and ACKs are received correctly, what is the sender utilization (Usender) when using:
- Stop and Wait:
- Go-Back-N:
- Selective Repeat:
Case 2: Now suppose ACK2 is missed and all other packets and ACKs are received correctly. The first packet and ACK are P0 and ACK0 respectively. Neglect the transmission time of ACK packets.
- Assume start sending at time 0, draw the timing diagram when using Stop and Wait, Go-Back-N, and Selective Repeat.
- Assume start sending at time 0, when does host A finish sending the last packet when using Stop and Wait, Go-Back-N, and Selective Repeat.
Draw here the timing diagrams
