File Transfer, without using the net..

[Accord Man]

situation:
2 PCs hooked to one router(threw wich they access the web)..


now when I transfer files from one to another -- using MSN messenger), the transfer rate is at around 3-4 m/s (would be faster but one of the PCs is very old -- P-100..)..


IS the transfer I described happenging via the net? Or only LAN?

I think its limited to LAN, since the upload speed with my ISP is like 25kb/s (and in this case I'm transfering at more than 150 times the ISP rate) ..

I'm in dooubt because I use MSN messenger to transfer, and it is web based.. So I'm kinda worried it may count in my monthly usage..