Network traffic monitoring. (which IP makes big traffic?)

Hi, My network has been very slower than before. Someone suspected the virus like nimda. So I have to found out who makes very high traffic.. I am not network engineer now. What things I have to know? and Which softwares I can select? I'm asking advice for you. Have a nice day. byebye -- T

Network traffic monitoring. (which IP makes big traffic?)

Hi, My network has been very slower than before. Someone suspected the virus like nimda. So I have to found out who makes very high traffic.. I am not network engineer now. What things I have to know? and Which softwares I can select? I'm asking advice for you. Have a nice day. byebye