ADC to gigabit MCU controler + time-stamp -- 2

MCU+ADC based board, when a trigger signal reaches the board, it should sample (12 bits) 6 analog signals and read the value of a 4 byte counter on an external clock (25 to 50 MHz). The 6 x 2 bytes values, plus the 4 bytes of the counter and board identifier will be streamed via Gigabit ethernet as UDP packets (about 1000 x 20-bytes events in every packet).
The board should sustain a trigger rate of the order of 1 Mevent/s or higher.