hassan

party paying floating rate - receives the fixed rate.
fixed rate was originally set up based on the LIBOR rates in effect at the time the swap originated.

If both payments are in the same currency - the payments would be netted and whoever (fixed payer or floating rate payer) owes more - pays the other.

Floating rate payer is receiving the fixed payment (without netting in effect). He swapped and received the fixed payment. So he locked in the fixed rate.
Fixed rate payer is receiving the floating payment (without netting). he swapped, received the floating payment. the lockin happens because the fixed rate at origination was based on the floating rates in effect at that time.... (you will see this in the Swaps chapter in derivatives).

CP