Method, device and system for data transmission

The invention provides a method, a device and a system for data transmission, wherein the method comprises the following steps of: receiving a first processing result of processing a first service request from a virtual gateway, and storing the first processing result in a random access memory, wherein the first service request is transmitted by a terminal; backing up the first processing result in the random access memory to a flash memory; if the first service request transmitted again by the terminal is received, judging whether the first processing result is in the random access memory, if not, loading the first processing result in the flash memory to the random access memory; reading the first processing result in the random access memory, and processing according to the first processing result. According to the method, the device and the system for data transmission provided by the invention, when the terminal transmits the same service request to a home gateway, the home gateway has no need of transmitting the service request to the virtual gateway every time, thus, signalling overhead may be reduced.