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10/100 Mbps Ethernet Controller Family Open Source Software Developer Manual 155
82550 and 82551QM Specific
Information B
This appendix applies to the Intel
®
82550 and 82551QM devices.
B.1 IPCB
The IP command block (IPCB) is new and used to activate the new offloading features of the
82550 and 82551. The value of the command field for IPCB is 9h. The relevant aspects of the
IPCB for each feature is described in the following subsections. This section summarizes the most
useful combinations of the IPCB fields.
NOTE: Source address insertion is not allowed when IPCB is used. Thus, the no source address insertion
(NSAI) bit of the configure command must be 1.
Table 69. IPCB Structure
Odd Word (D31:D16) Even Word (D15:D0) Offset
E
L
S I CID (5 bits) 000
N
C
CMD = 1001 C X
O
K
U XXXX XXXX XXXX (12 bits)
0h
Link Address (32 bits)
4h
TBD Array Address (32 bits)
8h
Maximum TCP Payload E
O
F
0 IPCB Byte Count (14 bits)
Ch
TBD Number Transmit Threshold
IP Activation (12 bits) Activation (20 bits)
10h
TCP Header Offset (8 bits) IP Header Offset (8 bits) VLAN (16 bits)
14h
Transmit Buffer #0 Address (32 bits)
18h
Reserved (32 bits)
Total TCP Payload (16 bits)
E
L
0
Transmit Buffer #0 Size (14 bits)
1Ch
Reserved (14 bits)
Table 70. IP Activation Bits (Byte 13)
15 14 13 12 11 10 9 8
000
Scheduled
Send
Reserved Reserved
Insert
VLAN
Hardware
Parse
Table 71. IP Activation Bits (Byte 12)
76543210
Large Send
TCP/UDP
Number
TCP/UDP
Checksum
IP
Checksum
XXXX