EP80579 Datasheet, PDF (1364/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
Table 37-1. Supported Receive Checksum Capabilities (Sheet 2 of 2)
IPv4 tunnels:
• IPv4 packet in an IPv4 tunnel
• IPv6 packet in an IPv4 tunnel
No
Yes (IPv4)
No
Yes^*
IPv6 tunnels:
• IPv4 packet in an IPv6 tunnel
No
No
• IPv6 packet in an IPv6 tunnel
No
No
Packet is an IPv4 fragment
Yes
No
Packet is greater than 1552 bytes
• LPE=1
Yes
Yes
Packet has 802.3ac tag
Yes
Yes
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
* _{The IPv6 header portion can include supported extension headers as}
described in the IPv6 Filter section.
Table 37-1 gives general details about what packets are processed. In more detail, the
packets are passed through a series of filters to determine if a receive checksum is
calculated.
37.5.5.8.1
MAC Address Filter
This filter checks the MAC destination address to be sure it is valid (e.g. DA match,
broadcast, multicast, etc.). The receive configuration settings determine which MAC
addresses are accepted. See the various receive control configuration registers such as
RCTL (RCTL.UPE, RCTL.MPE, RCTL.BAM), MTA[127:0], RAL, and RAH.
37.5.5.8.2
SNAP/VLAN Filter
This filter checks the next headers looking for an IP header. It is capable of decoding
Ethernet II, Ethernet SNAP, and IEEE 802.3ac headers. It will skip past any of these
intermediate headers and will look for the IP header. The receive configuration settings
determine which next headers are accepted. See the various receive control
configuration registers such as RCTL (RCTL.VFE), VET, and VFTA[127:0].
37.5.5.8.3
IPv4 Filter
This filter checks for valid IPv4 headers. The version field is checked for a correct value
(i.e. 4). IPv4 headers are accepted if they are any size greater than or equal to 5
(dwords). If the IPv4 header is properly decoded, the IP checksum will be checked for
validity. The RXCSUM.IPOFL bit must be set for this filter to pass.
37.5.5.8.4 IPv6 Filter
This filter checks for valid IPv6 headers, which are a fixed size and have no checksum.
The IPv6 extension headers accepted are: Hop-by-Hop, Destination Options, and
Routing. The maximum size next header accepted is 16 dwords (64 bytes).
All of the IPv6 extension headers supported by the GbE have the same header
structure, as shown in Figure 37-15.
Figure 37-15.IPv6 Extension Header Structure
Byte 0
Byte 1
Byte 2
Byte 3
Intel^® EP80579 Integrated Processor Product Line Datasheet
1364
August 2009
Order Number: 320066-003US