I was looking how to do this to test a monitoring system using GNS 3, and came across this little gem

http://etherealmind.com/the-poor-mans-ios-traffic-generator/

nothing fancy just enabling the small TCP servers (#service tcp-small-servers), but a nice simple way to push some data across a link between two routers. The article also mentions some other methods so will be looking in to them as well.

Always nice to be able to test some things with out having to fire up servers or other hard/soft ware 🙂