MAC_IPG_IFG_IPGT_SHIFT
#define MAC_IPG_IFG_IPGT_SHIFT 0 /* Desired back to back
#define MAC_IPG_IFG_IPGT_SHIFT 0 /* Desired back to back inter-packet gap. The default is 96-bit time */
#define MAC_IPG_IFG_IPGT_SHIFT 0