[Osiris]

Bandwidth in computer networking refers to the data rate supported by a network connection or interface. One most commonly expresses bandwidth in terms of bits per second (bps). The term comes from the field of electrical engineering, where bandwidth represents the total distance or range between the highest and lowest signals on the communication channel (band).

Bandwidth represents the capacity of the connection. The greater the capacity, the more likely that greater performance will follow, though overall performance also depends on other factors, such as latency.

Here is the list of bandwidth monitoring tools for your network bandwidth

bmon
bwbar
bwm
bwm-ng
iftop
iperf
ipfm
speedometer
cbm
ibmonitor
pktstat
mactrack
MRTG
Cacti

http://www.ubuntugeek.com/bandwidth-...ntu-users.html