The trace command is used to visually see a network packet being sent and received and the amount of hops required for that packet to get to its destination.

Trace was created 1987 by Van Jacobson from a suggestion by Steve Deering, with particularly cogent suggestions or fixes from C. Philip Wood, Tim Seaver and Ken Adelman. It was originally created for unix and is called traceroute there.  In microsoft it is called tracert and in cisco ios it is called trace.

Good webpage about tracert in microsoft windows is

http://support.microsoft.com/kb/162326

And for cisco ios

http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_tech_note09186a00800a6057.shtml