Line discipline co-ordinate the link system. It determines which device can send and when it can send. Line discipline decides the role of a device on a network.
Computer Networks MCQ - Computer Networks Section 2
For stop-and-wait flow control for n data packets sent, in acknowledgements are needed.
A crossbar switch connects n inputs to m outputs in a grid, using electronic micro switches at each cross point, totally n x m cross points are required for crossbar switch. In general 25 percent of the cross points are used at a given time. The rest are idle so, totally 1000 cross points, so 25% = 250 crosspoint points are in use.
In time division switch, slots are divided by time switching accomplished using time division multiplexing (TDM) and another device called time slot interchange (TSI).

