The GT Quad interface is clocked by rx_alt_serdes_clk[0] through rx_alt_serdes_clk[5] in the DCMAC Subsystem RX direction and by tx_alt_serdes_clk[0] through
tx_alt_serdes_clk[5] in the DCMAC Subsystem TX direction. The rx_serdes_clk[N] connects to a GT Quad transceiver generated clock whose
frequency is twice the frequency of rx_alt_serdes_clk[N]. Similarly, the tx_serdes_clk[N] connects to a GT Quad transceiver generated clock whose
frequency is twice that of tx_alt_serdes_clk[N].