Swap payments are usually netted against each other, rather than actually exchanged. That is, the counterparty with a positive position will receive a net amount equivalent to the difference between the amount owed to him and the amount owed by him:

Net amount receivable = amount receivable – amount payable

or likewise,

Net amount payable = amount payable – amount receivable

For example, in a floating to fixed-rate swap, suppose the fixed rate is 7.5%. If the LIBOR rate for a given period is 6%, then the fixed rate payer will be at a disadvantage as he has to pay the rate difference to the fixed rate receiver (the floating rate payer):

Net amount payable by the fixed rate payer = 7.5%- 6% = 1.5%

If, on the contrary, the LIBOR rate is trading above the fixed rate (say at 8%), then:

Net amount receivable by the fixed rate payer = 8% – 7.5% = 0.5%

On some rare occasions, the rates on the two legs might be equal, and hence the net amount of swap is zero.