82583V Datasheet, PDF (159/374 Pages) Intel Corporation – Intel® 82583V GbE Controller

Inline Functions—82583V GbE Controller
7.3.6.2.3
Note:
IPv4 Header
• IP Identification: incremented from last value (wrap around)
• IP Total Length = MSS + HDRLEN - IPCSS
• IP Checksum
IPv6 Header
• Payload Length = MSS + HDRLEN - IPCSS - Ipv6Size (while Ipv6Size = 40Bytes)
TCP Header
• Sequence Number update: Add previous TCP payload size to the previous sequence
number value. This is equivalent to adding the MSS to the previous sequence
number.
• If FIN flag = 1b, it is cleared in these frames.
• If PSH flag =1b, it is cleared in these frames.
• TCP Checksum
UDP Header
• UDP Length: MSS + HDRLEN - TUCSS
• UDP Checksum
TCP/IP/UDP Header for the Last Frame
The hardware makes the following changes to the headers of the last packet that is
derived from each TCP segmentation context.
Last frame payload bytes = PAYLEN - (N * MSS)
MAC Header (for SNAP Packets)
• Type/Len field = Last frame payload bytes + HDRLEN - 14
IPv4 Header
• IP Total Length = (last frame payload bytes + HDRLEN) - IPCSS
• IP Identification: incremented from last value (wrap around)
• IP Checksum
IPv6 Header
• Payload Length = last frame payload bytes + HDRLEN - IPCSS - Ipv6Size (while
Ipv6Size = 40Bytes)
TCP Header
• Sequence Number update: Add previous TCP payload size to the previous sequence
number value. This is equivalent to adding the MSS to the previous sequence
number.
• If FIN flag = 1b, set it in this last frame
• If PSH flag =1b, set it in this last frame
• TCP Checksum
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