Downlink Credit Based Flow Control (DCBFC)

The procedure is used by a Transparent Client to enable Downlink Credit Based Flow Control for the Transparent Server. Once it is enabled, Client role can only send data to Server while the credit count is greater than zero.

When enabling Downlink Credit Based Flow Control, Client shall write TCP characteristic handle with “Downlink Credit Based Flow Control Enable” opcode (0x14) to the Transparent Control Point on Transparent Server. And the Transparent Server shall send the MTU value and available credit numbers to Transparent Client by Response Parameters of 0x00 opcode. Transparent Client will check the credit count to know how many data can be transmitted to the Transparent Server by performing the write command operation to TDD Characteristic handle. The Credit count will be decreased by the number of ATT packet sending by Transparent Client. Transparent Client can send data only while the credit count is greater than zero. Transparent Server shall return the credit to Transparent Client after the received data has been processed completed.