Receive and Transmit Description

TCP Length = Payload + HDRLEN - TUCSS

“Payload” is normally MSS except for the last packet where it represents the remainder of the payload.

0

31

IP Source Address

IP Destination Address

Zero

Layer 4 Protocol

ID

TCP Length

Figure 3-13. TCP Pseudo Header Content (Traditional Representation)

IP Source Address

IP Destination Address

Upper Layer Packet Length

Zero

Next Header

Figure 3-14. TCP PseudoHeader Content for IPv6

Note: The IP Destination address is the final destination of the packet. Therefore, if a routing header is used, the last address in the route list is used in this calculation. The upper-layer packet length is the length of the TCP header and the TCP payload.

The UDP header is always 8 bytes in size with no options.

 

 

 

 

 

 

 

 

 

 

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Source Port

 

 

 

 

 

 

 

 

 

 

 

Destination Port

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Checksum

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 3-15. UDP Header (Traditional Representation)

Byte3

Byte2

Byte1

Byte0

0

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Destination Port

 

 

 

 

 

 

 

 

 

 

 

 

 

Source Port

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Checksum

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Length

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 3-16. UDP Header (Little-Endian Order)

Software Developer’s Manual

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Image 77
Intel Intel Gigabit Ethernet Controllers, PCI-X Source Port Destination Port Length Checksum, Byte3 Byte2 Byte1 Byte0