82598EB Datasheet, PDF (243/596 Pages) Intel Corporation – Intel® 82598EB 10 Gigabit Ethernet Controller Datasheet

Intel^® 82598EB 10 GbE Controller - Receive Functionality
IPv6 extension headers have a specified order. However, destinations must be able to process these
headers in any order. Also, IPv6 (or IPv4) can be tunneled using IPv6, and thus another IPv6 (or IPv4)
header and potentially its extension headers can be found after the extension headers.
The IPv4 Next Header Type is at byte offset 9. In IPv6, the first Next Header Type is at byte offset 6.
All IPv6 extension headers have the Next Header Type in their first 8 bits. Most have the length in the
second 8 bits (Offset Byte[1]) as follows:
Table 3-60. Typical IPv6 Extended Header Format (Traditional Representation)
1
2
3
0 1 2 3 4 5 6 7 8 9 0 12 3 4 5 6 7 8 9 0 1 2 3 4 5 67 8 9 0 1
Next Header Type
Length
Table 3-61 lists the encodings of the Next Header Type field, and information on determining each
header type's length. The IPv6 extension headers are not otherwise processed by the 82598 so their
details are not covered here.
Table 3-61. Header Type Encodings and Lengths
IPv6
IPv4
Header
TCP
UDP
Hop by Hop Options
Header
Destination Options
Routing
Fragment
Authentication
Next Header Type
6
4
6
17
0 note 1
Next Header Type
60
43
44
51
Header Length
Always 40 bytes
Offset Bits[7:4]
unit = 4 bytes
Offset Byte[12]. Bits[7:4]
unit = 4 bytes
Always 8 bytes
8+Offset Byte[1]
Header Length
8+Offset Byte[1]
8+Offset Byte[1]
Always 8 bytes
Note 3
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