They are similar but they answer different questions.
By default, iftop will tell you "this network interface on your machine is talking a lot to ycombinator.com". But you don't necessarily know which processes are doing the most talking collectively.
This will tell you "Firefox process 4567 is talking a lot ycombinator.com" and you'll know whether 4567 is also one of the chattiest talkers right now.
By default, iftop will tell you "this network interface on your machine is talking a lot to ycombinator.com". But you don't necessarily know which processes are doing the most talking collectively.
This will tell you "Firefox process 4567 is talking a lot ycombinator.com" and you'll know whether 4567 is also one of the chattiest talkers right now.