Which switch is a multistage switch with micro switches at each stage that route the packets based on the output port represented as a binary string?

A station in a network forwards incoming packets by placing them on its shortest output queue. What routing algorithm is being used?

The probability that a single bit will be in error on a typical public telephone line using 4800 bps modem is 10 to the power -3. If no error detection mechanism is used, the residual error rate for a communication line using 9-bit frames is approximately equal to