1. A method of limiting the size of synchronization messages between a first synchronization device and a second synchronization device, the method comprising the steps of: specifying, in the first device, a maximum message size for synchronization messages to be sent to the first device, transmitting information on the maximum message size from the first device to the second device, and transmitting to the first device one or more synchronization messages which are equal to or smaller than the maximum message size of the first device.