Splitting Fragmented IP Frames
If a fragmented IP frame contains the upper-layer-protocol header, a NIC must split the frame at the beginning of upper-layer-protocol header or must not split the frame. That is, the NIC must not split fragmented IP frames at the beginning of the TCP or UDP payload.
If a fragmented IPv4 frame does not contain the upper-layer-protocol header, the NIC must split the frame at the beginning of the UDP or TCP payload or must not split the frame.
If a fragmented IPv6 frame does not contain the upper-layer-protocol header, the NIC must not split the frame.
For more information about splitting frames at the beginning of the upper-layer-protocol header, see Splitting Frames at the Beginning of the Upper-Layer-Protocol Headers.