I'm studying for an exam and I'm going over review problems my professor has given me. I'm having trouble understanding Switching. Can someone explain to me how to do the following switching problem?

Two hosts A and B are connected by two switches S1 and S2 as indicated below. Each link has a bandwidth of 1000 Mbps and the delay of 10 ms Calculate the time take to transfer 10^3 bits of data from A to B in the following cases:

```
A---S1---S2---B
```

A.) S1 and S2 do message switching.

B.) S1 and S2 do packet switching. Assume that there is no header required for the packets and the packets are p bytes long.

C.) If we have to include a header of length h bits for each packet for routing purposes and we choose to send packets of size p, how much time will it tale to transfer the whole file?