Forward the credit card transaction request to the front-end system of the bank for processing, and then return the processing result to the merchant. According to the query of financial network, the UnionPay front-end system is used to handle the exchange business between banks and UnionPay, and is mainly responsible for the message format conversion between the intra-bank system and UnionPay processing center. Among them, the credit card forwarding front-end belongs to a business in the UnionPay front-end system.