82583V Datasheet, PDF (146/374 Pages) Intel Corporation – Intel® 82583V GbE Controller

82583V GbE Controller—Inline Functions
7.2.9.1.7
VLAN Field
The VLAN field is used to provide the 802.1Q/802.1ac tagging information. The VLAN
field is ignored if the VLE bit is 0b or if the EOP bit is 0b.
15
13
12
PRI
CFI
11
0
VLAN tag
7.2.9.2
Context Transmit Descriptor Format
63
0 _TUCSE
8 _MSS
63
TUCSE, TUCSS, TUCSO are
TCP/UDP Checksum Controls
IPCSE, IPCSS, IPCSO are IP
Checksum Controls
48 47
40 39
32 31
16 15
87
0
TUCSO
TUCSS
IPCSE
IPCSO IPCSS
HDRLEN RSV STA TUCMD DTYP PAYLEN
48 47
40 39 36 35 32 31
24 23 20 19
0
Figure 35.
Status
Command
3
2
1
0
7
6
5
4
32
1
0
3
2
1
0
RSV
DD IDE SNAP DEXT RSV RS TSE IP TCP
DTYP
DEXT must =1
for context
descriptor format
DTYP must =0000
for context
descriptor format
Context Transmit Descriptor Format
The context descriptor provides access to the enhanced checksum off load and TCP
segmentation features available in the 82583V.
A context descriptor differs from a data descriptor as it does not point to packet data.
Instead, this descriptor provides access to on-chip contexts that support the transmit
checksum offloading or the segmentation feature of the 82583V. A context refers to a
set of parameters loaded or unloaded as a group to provide a particular function.
To select this descriptor format, the DEXT bit in the command field should be set to 1b
and TDESC.DTYP should be set to 0x0000. In this case, the descriptor format is defined
as shown in Figure 35.
7.2.9.2.1
IP and TCP/UDP Checksum Control
The first Qword of this descriptor type contains parameters used to calculate the two
checksums, which can be offloaded.
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