The simple answer is that an Interest Rate Swap (IRS) is Over The Counter (OTC) while a Futures Contract is Exchange Traded.

The swap rate for a particular maturity is the average of the bid and offer fixed rates that a market maker is prepared to exchange for LIBOR in a standard plain vanilla swap with that maturity. The swap rate for a particular maturity is the LIBOR/swap par yield for the maturity. The swap rate can also be defined as the fixed rate in an interest rate swap that causes the swap to have a value of zero.

A cross surrency swap has elements of both currency and interest rate transactions.

An Overnight Index Swap (OIS) is an interest rate swap involving the exchange of an overnight (floating) interest rate for some fixed interest rate. OIS's are mainly used by banks to hedge the risk inherent in overnight interest rate fluctuations. By swapping floating/fixed interest rates, banks can insulate themselves to some extent from any adverse interest rate swings. *Keep in mind that forex markets are active 24/7 because when one major financial center like London is closing for the night, another is opening in the morning somewhere else in the world.

In Interest rate swaps, each party agrees to pay either a fixed or a floating rate in a particular currency to the other party. The fixed or floating rate is multiplied with the Notional Principal Amount (NPA) say Rs. 1 lac. This notional amount is not exchanged between the parties involved in the Swap. This NPA is used only to calculate the interest flow between the two parties.

The most common interest rate swap is where one party 'A' pays a fixed rate to the other party 'B' while receiving a floating rate which is pegged to a reference rate like LIBOR