Intel Extensible Firmware Interface - Manual (Page 917)

32/64-Bit UNDI Specification
Version 1.10 12/01/02 E-51
// Media header length. This is the typical media header
// length for this UNDI. This information is needed when
// allocating receive and transmit buffers.
PXE_UINT16 MediaHeaderLen;
// Number of bytes in the NIC hardware (MAC) address.
PXE_UINT16 HWaddrLen;
// Maximum number of multicast MAC addresses in the multicast
// MAC address filter list.
PXE_UINT16 MCastFilterCnt;
// Default number and size of transmit and receive buffers that
// will be allocated by the UNDI. If MemoryRequired is
// nonzero, this allocation will come out of the memory buffer
// given to the Initialize command. If MemoryRequired is zero,
// this allocation will come out of memory on the NIC.
PXE_UINT16 TxBufCnt;
PXE_UINT16 TxBufSize;
PXE_UINT16 RxBufCnt;
PXE_UINT16 RxBufSize;
// Hardware interface types defined in the Assigned Numbers RFC
// and used in DHCP and ARP packets.
// See the PXE_IFTYPE typedef and PXE_IFTYPE_xxx macros.
PXE_UINT8 IFtype;
// Supported duplex options. This can be one or a combination
// of more than one constants defined as PXE_DUPLEX_xxxxx
// below. This value indicates the ability of UNDI to
// change/control the duplex modes of the NIC.
PXE_UINT8 SupportedDuplexModes;