In the modern day world, the business domain is becoming more and more competitive. Hence more speed is always preferable because it gives competitive edge to the merchant/business owner.
For facilitating them, cutting edge technology has helped faster and more secured transmission of informations. Such a technology used in credit card payment processing is known as E commerce ASP Service and the payment mode is known as Payment Gateway.
This is a completely network based online service routed through a third party vendor who facilitate in verifying the credit card informations on a real time basis. Find detailed on the fundamentals of credit card: