How can I see what is using all my bandwidth on cisco IOS?

I have a cisco router performing NAT for my local network. Download bandwidth is stagnant at 2MB/s and I'm not sure w开发者_JAVA百科hich host is responsible for this and what exactly it's connecting to. How can I find this? Thank you.

On your external interface use:

interface {interface} {interface_number}
ip route-cache flow
bandwidth <kbps>
exit

Then use the command below to get some data about usage:

show ip cache flow