nload ::
nload is a console application which monitors network traffic and bandwidth usage in real time.

To install :
$sudo apt-get install nload

bmon :

bmon is a portable bandwidth monitor with multiple input methods and output modes.

To install :

$sudo apt-get install bmon

Iptraf :

IPTraf is a console-based network statistics utility for Linux. It gathers a variety of figures such as TCP connection packet and byte counts, interface statistics and activity indicators, TCP/UDP traffic breakdowns, and LAN station packet and byte counts

To install
$sudo apt-get install iptraf