struct NETWORK_LOADER_BLOCK

typedef struct _NETWORK_LOADER_BLOCK
{
     UCHAR * DHCPServerACK;
     ULONG DHCPServerACKLength;
     UCHAR * BootServerReplyPacket;
     ULONG BootServerReplyPacketLength;
} NETWORK_LOADER_BLOCK, *PNETWORK_LOADER_BLOCK;

Windows Vista Kernel Structures