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Allocating the Header Buffer

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NDIS specifies the maximum header size that a miniport driver should allocate in the MaxHeaderSize member of the NDIS_HD_SPLIT_ATTRIBUTES structure. For more information about setting header-data split attributes, see Initializing a Header-Data Split Provider.

When a NIC splits the header and data in a received Ethernet frame, the size of the header portion of the indicated Ethernet frame must not exceed the MaxHeaderSize value.

If an IP header contains IPv4 options, IPsec headers, or IPv6 extension headers, and if the header exceeds the MaxHeaderSize value, the NIC must not split the frame.

If a header that includes the UDP header, TCP header, or TCP options exceeds the MaxHeaderSize value, the NIC must either split the frame at the beginning of the upper-layer-protocol header or must not split the frame.