L2 Datalink Layer | Flow Control Numerical problems on stop and wait, go-back-n , selective repeat

This video is about solving problems based on stop and wait protocol , go-back-n protocol and selective repeat protocol. 1. Frames of 1000 bits are sent over a 1-Mbps channel using a geostationary satellite whose propagation time from the earth is 270 msec. Acknowledgements are always piggybacked onto data frames. The headers are very short. Three-bit sequence numbers are used. What is the maximum achievable channel utilization for (a) Stop-and-wait? (b) Go-back-N? (c) Selective Repeat? 2. A 100-km-long cable runs at the T1 data rate. The propagation speed in the cable is 2/3 the speed of light in vacuum. How many bits fit in the cable?