Measuring ISP speed for my router

Hello
I am trying to develop a small program that will periodically (say every 6 hrs) calculate my ISP broadband speed (both up and dn stream) and display on my router GUI's WAN page. I am thinking of say, start a Linux timer, start down/uploading a file of a known size, stop timer and then calculate the U/D speed of the ISP.
Any good suggestions, sample program etc would be of great help. If there are open source programs out there that already does this, a link would be good.
Appreciate any/all the help!

thanks
rhine

You could do all this in scripts using wget/wput to get the files and date to save the starting and ending times (date can return to you epoch time) then some simple math in the shell script and wham. . . there is your status.