The client is not comfortable using CCAvenue/PayTm or any third party gateways. He wants to have a payment gateway that is linked directly with his bank account (Union Bank of India). Having no clue, wrote a letter to the technical team of Union Bank of India and they are asking for payment protocol to be furnished (in the meantime asked them for clarification). Not sure what it means. I would like to know is it really possible to have a payment gateway bypassing the world of CCAvenue/Paypal/PayTms, and if so the procedure for the same (tutorial).
Third party payment gateways are used as a low cost alternative to rolling your own payment processing system. Most payment gateways (much the same as in store credit card machines) work by processing one or more payments in a given timeframe and then processing the deposit into your nominated bank account. Can't speak specifically for India but here in Australia we use hosted payment gateways all the time for credit card processing and the funds are cleared into the business bank account overnight. Larger businesses quite often use their own payment processing in house in that they process the credit card transaction however they generally still have to work with some payment processing service such as their banks in order to get the payment itself processed, but even then the funds don't hit the business bank accounts in real time, instead they are processed in batched, which can be anywhere from a few hours to 1-2 business days depending on how frequently the banks involved process inter-bank payment runs.
In short yes it is possible to bypass the major payment gateways and roll your own linked to your bank but the costs associated with it are so phenomenal that only the real large enterprises that process payments all the time can justify the initial capital investment in infrastructure, legal, and compliance. By rolling your own payment gateway you are also getting into a much greater level of scrutiny when it comes to PCI-DSS certification which is the payment card industry data security standards which must be complied with in order to be accepted by the worlds payment card services (Mastercard, Visa, etc) for processing payments.