App to Measure Network Volume?

[Kynan Shook]

I'm surprised nobody has mentioned this one yet: Activity Monitor.  
Included as part of OS 10.3 or later.  I always have it running, mostly 
for the CPU monitor portion (lets me know if there's a hung application 
or something using up a lot of CPU power, which helps me keep the 
computer cool).  However, I also use it a lot for its Network Activity 
portion.  It has a graph of the last minute or so of network activity, 
keeps track of the highest throughput since the application was 
launched, shows current packets in and out per second, current data in 
and out per second, packets in/out since last reboot, and total amount 
of data in/out since last reboot.  There's a similar section for drive 
activity (tracking reads and writes over time).  There's also graphs of 
disk usage and memory usage.

The downside is that this isn't saved when rebooting; if your computer 
crashes (in OS X?  Ha!) and you don't write the numbers down, you'll 
have no idea what they were.  But it's free, requires no installation, 
and works well.

Johndan Johnson-Eilola <johndan at clarkson.edu> writes:
> This is slightly off topic, but is anyone aware of an application that
> would measure the volume of data uploaded and downloaded over network
> connections on a TiBook (i.e., number of k or megs over time). I'd like
> to calculate my average data production/consumption via the network for
> a project I'm working on. (I could probably manually calculate these
> things by studiously logging every email, instant message, Internet
> radio stream, weblog posting, etc., but the measurement would probably
> affect the activities themselves.