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Receive and Transmit Description
Software Developer’s Manual 33
Table 3-6. 82544GC/EI Supported Receive Checksum Capabilities
Table 3-5 lists the general details about what packets are processed. In more detail, the packets are
passed through a series of filters (Section 3.2.9.1 through Section 3.2.9.5) to determine if a receive
checksum is calculated.
Note: (Section 3.2.9.1 through Section 3.2.9.5) does not apply to the 82544GC/EI.
3.2.9.1 MAC Address Filter
This filter checks the MAC destination address to be sure it is valid (IA match, broadcast,
multicast, etc.). The receive configuration settings determine which MAC addresses are accepted.
See the various receive control configuration registers such as RCTL (RTCL.UPE, RCTL.MPE,
RCTL.BAM), MTA, RAL, and RAH.
IPv4 Packet has IP options
(IP header is longer than 20 bytes)
Yes Yes
Packet has TCP or UDP options Yes Yes
IP header’s protocol field contains a
protocol # other than TCP or UDP.
Yes No
a. The IPv6 header portion can include supported extension headers as described in the IPv6 Filter
section.
b.For the 82541xx and 82547GI/EI, frame sizes greater than 2 KB require full-duplex operation.
Table 3-5. Supported Receive Checksum Capabilities
Packet Type
HW IP Checksum
Calculation
HW TCP/UDP Checksum
Calculation
Packet Type
HW IP Checksum
Calculation
HW TCP/UDP
Checksum Calculation
IP v4 packets Yes Yes
IP v6 packets
(no IP checksum in IPv6)
No No
Packet is an IP fragment Yes No
Packet is greater than 1552 bytes; (LPE=1) Yes Yes
Packet has 802.3ac tag Yes Yes
Packet has IP options
(IP header is longer than 20 bytes)
Yes Yes
Packet has TCP or UDP options Yes Yes
IP header’s protocol field contains a protocol
other than TCP or UDP.
Yes No