When looking for a good network connection speed, why does “bandwidth” not tell the whole story?

Question

While I was listening in on an interesting conversation about distributed systems, I heard people talk about how overhead and "gap" were two important characteristics of distributed systems, and how bandwidth is not a good measure for the speed. Can someone explain why this is true?

I guess we can start off with Remote Procedure Calls on a remote filesystem, to begin with. Anything will do.

Answer 1

Bandwidth is not a measure of speed, it's a measure of capacity.

Generally speaking, latency is a measure of speed.

There are many factors that determine the useful throughput (goodput) of any communications network (protocol overhead, etc.).