We have discussed high latency a bit in my previous HakTip, but I wanted to go into it with some more detail. As you look at packets in a Wireshark capture, you'll notice that with a normal connection, your transmission happens in under a second. Now if you look at a few packets with slow communication, they show up to be almost a second each. This would be called wire latency because of the slowness happening on the wire, not the source or destination.
Find out more about Wireshark here or checkout this more comprehensive list of monitoring tools here.