Intel PCI-X, Intel Gigabit Ethernet Controllers manual Ipofld, Tuofld, IPV6OFL

Register Descriptions

Field	Bit(s)	Initial	Description
		Value
			Packet Checksum Start
			Controls the starting byte for the Packet Checksum
			calculation. The Packet Checksum is the one’s complement
			over the receive packet, starting from the byte indicated by
			RXCSUM.PCSS (0b corresponds to the first byte of the
			packet), after stripping. For example, for an Ethernet II frame
			encapsulated as an 802.3ac VLAN1 packet and with
PCSS	7:0	0b	RXCSUM.PCSS set to 14, the packet checksum would
			include the entire encapsulated frame, excluding the 14-byte
			Ethernet header (DA,SA,Type/Length) and the 4-byte VLAN
			tag. The Packet Checksum does not include the Ethernet
			CRC if the RCTL.SECRC bit is set. Software must make the
			required offsetting computation (to back out the bytes that
			should not have been included and to include the pseudo-
			header) prior to comparing the Packet Checksum against the
			TCP checksum stored in the packet.
			IP Checksum Off-load Enable
			RXCSUM.IPOFLD is used to enable the IP Checksum
			offloading feature. If RXCSUM.IPOFLD is set to 1b, the
			Ethernet controller calculates the IP checksum and indicates
IPOFLD	8	0b	a pass/fail indication to software through the Checksum Error
			bit (CSE) in the ERROR field to the receive descriptor. If both
			RXCSUM.IPOFLD and RXCSUM.TUOFLD are set, the
			Checksum Error bit (CSE) is set if either checksum was
			incorrect. If neither RSCSUM.IPOFLD nor
			RXCSUM.TUOFLD is set, the Checksum Error bit (CSE) is
			be 0b for all packets.
			TCP/UDP Checksum Off-load Enable
			RXCSUM.TUOFL is used to enable the TCP/UDP Checksum
			off-loading feature. When set to 1b, the Ethernet controller
			calculates the TCP or UDP checksum and indicate a pass/fail
TUOFLD	9	0b	indication to software through the Checksum Error bit (CSE).
			If both RXCSUM.TUOFLD and RXCSUM.TUOFLD are set,
			the Checksum Error bit (CSE) is set if either checksum was
			incorrect. If neither RXCSUM.IPOFLD nor
			RXCSUM.TUOFLD is set, the Checksum Error bit (CSE) is
			0b for all packets.
			IPv6 Checksum Offload Enable
IPV6OFL2	10	0b	If IPV6OFL is set to 1b, hardware parses IPv6 headers when
			parsing a receive packet. This applies to checksum offloading
			only.
Reserved	31:11	0b	Reserved
			Reads as 0b. Should be written with 0b for future
			compatibility.

1.Not applicable to the 82541ER.

2.Not applicable to the 82544GC/EI.

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