1. A description of the service:

E-commerce has taken the developed countries by storm in the recent years. It has allowed people to buy goods from anywhere in the world by just click of a button. Formally speaking e-commerce allows people to exchange goods and services immediately and with no barriers of time or distance. Any time of the day or night, one can go online and buy almost anything one may want. The following g processes are involved in an E-commerce site:

Step 1 - The consumer places an order
A customer visits the website. The customer goes through interactive catalogue to find something of interest and places an order at the storefront by entering pertinent information, such as their name, address and credit card information. Merchants may also enter an order on the customer's behalf through the Virtual Terminal.
Step 2 - The transaction processes in real-time
The payment gateway provides secure, real-time connectivity from the storefront of the site to the payment gateway platform. The "order now" button on the website is linked to the payment gateway, which routes and obtains the credit card authorization or declination code. The credit card is checked against the address verification system to authenticate the card holder.
Step 3 - The transaction is approved or declined
The customer completes the transaction by submitting a transaction receipt to the server before disconnecting. The payment gateway then confirms that the transaction has been securely routed and processed. As proof of the securely processed transaction, both the customer and the merchant receive a transaction confirmation number.
Step 4 - The transaction is settled
The approved accumulated transactions from the current day, known as a batch, are sent to the merchant’s processor at the end of the day to settle their business checking account within 48 business hours.
Source: www.howstuffworks.com