Intel Gigabit Ethernet Controllers Benutzerhandbuch

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The Ethernet controller supports a total of four flexible filters. Each filter is configured to 

recognize any arbitrary pattern within the first 128 bytes of the packet. To configure the flexible 
filter, the software driver must mask values into the Flexible Filter Mask Table (FFMT), the 

required values into the Flexible Filter Value Table (FFVT), and the minimum packet length into 

the Flexible Filter Length Table (FFLT). These contain separate values for each filter. The software 
driver must also enable the filter in the Wakeup Filter Control Register (WUFC) as well as the 

overall wakeup functionality by setting PME_En in the Power Management Control Status 

Register or the Wakeup Control Register.

Once enabled, the flexible filters scan incoming packets for a match. If the filter encounters any 
byte in the packet where the mask bit is 1b and the byte doesn’t match the byte programmed in the 

Flexible Filter Value Table (FFVT), then the filter failed that packet. If the filter reaches the 

required length without failing the packet, it passes the packet and generates a wakeup event. It 
ignores any mask bits set to 1b beyond the required length. (the wakeup packet is stored, see 

For the 82541xx and 82547GI/EI, the flexible filter does not have any way to automatically skip 

VLAN or LLC/SNAP headers. If such headers are included, the offsets of the subsequent fields 
must be adjusted accordingly.

This following flexible packet filters are listed for reference only.

1.

82541xx and 82547GI/EI only.

6

Destination Address

Compare

MAC Header – 
processed by 
main address filter

6

Source Address

Skip

S = (0/4)

Possible VLAN Tag

Compare or 
Skip

D = (0/8)

Possible LLC/SNAP Header

Compare or 
Skip

2

Type

8137h

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IPX

16

Some IPX Stuff

-

Ignore

2

IPX Diagnostic Socket

0456h

Compare