In reply to chr_sue:
interface mdio_if (input bit phy_mdc,clk);
wire phy_mdio;
bit phy_rst_n_0;
bit phy_rst_n_1;
bit phy_intr_0;
bit phy_intr_1;
endinterface
module top_tb();
mdio_if mdio(phy_mdc,clk);
test_top DUT(.clk_p (clk_p),
.phy_mdc (phy_mdc),
.phy_mdio (mdio.phy_mdio),
.phy_rst_n_0 ( mdio.phy_rst_n_0),
.phy_rst_n_1 ( mdio.phy_rst_n_1),
.phy_intr_0 ( mdio.phy_intr_0), .phy_intr_1 ( mdio.phy_intr_1));
like this u said right ?