I'm trying to solve these two problems as it would be useful info:

A) A computer is transmitting data using a sliding window protocol. The packets are all of a constant size of 600 bytes. If you wish to limit the connection to a maximum link utilisation of 50%, what would the window size be, expressed as a number of packets. The link has a capacity (bandwidth) of 8Mbit/s and an end to end propagation delay of 12ms.

B) Calculate the frame size in an Ethernet made of optical fibre if the system length were 10km and the bit rate was 10Gbit/s (assume the speed of light in fibre is 2* 108m/s)? What are the implications of this frame size for the sending of an acknowledgement?

If anyone can give me some pointers, it would be much appreciated.

Thanks in advance.