Basically, I know that Unicast is one to one, Multicast is one to many (the ones that requested the data) and Broadcast is one to all (whether they want the data or not).
In unicast, a data is duplicated and sent one by one by the transmitter to all the receivers that need it. Bandwidth usage here is simply equal to data size * number of receivers, right ?
But how does that work for multicast and broadcast transmissions ? I understood that it is simpler (and more cost effective) for the transmitter that has to send the data just once to the switch (no matter how many receivers). Then the switch takes care of it by forwarding the data to many (multicast) or to all (broadcast). But in the end, the bandwidth usage will increase with the number of receivers too. That means (as before) multiplying the data size by the number of receivers, right ?
For example, is the bandwidth usage of 100 unicast transmissions different from 1 broadcast (or multicast) transmission to 100 receivers ? If so, what’s the trick ?
Many thanks for your time