A clock synchronization system with IEEE 1588–2008 adapters over existing Gigabit Ethernet equipment

This paper presents an IEEE 1588-2008 adapter that provides existing Gigabit Ethernet equipment with the functionalities required to clock synchronization on the order of sub-microsecond. To compensate the time error caused by the queuing delays in the Gigabit Ethernet equipment, the adapter measures the residence time and runs the peer delay mechanism for the equipment. Major functional blocks including the clock synchronization cores, Media Access Controls (MACs), and frame buffers have been integrated into a 21 mm² silicon chip in 0.18 μm CMOS process. Experimental results show that the end devices can be synchronized within ±20 ns by simply attaching the proposed IEEE 1588-2008 adapters to the ordinary switches that connects the end devices.