82598EB Datasheet, PDF (214/596 Pages) Intel Corporation – Intel® 82598EB 10 Gigabit Ethernet Controller Datasheet

Intel^® 82598EB 10 GbE Controller - Receive Functionality
• Else – a single copy of the following registers is used (register # 0).
Registers included in this category are:
• DCA_RXCTRL[15:0] – Rx DCA Control
• SRRCTL[15:0] – Split and Replication Receive Control
• PSRTYPE[15:0] – Packet Split Receive Type
3.5.2.1 Packet Filtering
The receive packet filtering role is determining which of the incoming packets are allowed to pass to the
local system, and which should be dropped. Received packets can be destined to the host, to a BMC, or
to both. This section describes how host filtering is done, and the interaction with management
filtering.
Note: Maximum supported received packet size is 16 kB.
As shown in Figure 3-20, host filtering is done in three stages:
1. Packets are filtered by L2 filters (MAC address, unicast/multicast/broadcast). See Section 3.5.2.1.1
for details.
2. Packets are then filtered by VLAN filters if a VLAN tag is present. See Section 3.5.2.1.2 for details.
3. Packets are filtered by the manageability filters (port, IP, flex, other). Refer to the Intel® 82598 10
GbE Controller System Manageability Interface application note for details.
A packet is not forwarded to the host if any of the following takes place:
1. The packet does not pass L2 filters.
• The packet does not pass VLAN filtering.
• The packet passes manageability filtering and the manageability filters determine that the packet
should not pass to host as well. Refer to the Intel® 82598 10 GbE Controller System
Manageability Interface application note for details.
A packet that passes receive filtering as previously described might still be dropped due to other
reasons. Normally, only good packets are received. These are defined as those packets with no Under
Size Error, Over Size Error, Packet Error, Length Error and CRC Error detected. However, if the Store-
Bad-Packet (SBP) bit is set (FCTRL.SBP), then bad packets that don't pass the filter function are stored
in host memory. Packet errors are indicated by error bits in the receive descriptor (RDESC.ERRORS). It
is possible to receive all packets, regardless of whether they’re bad, by setting promiscuous enables
and the SBP bit.
Note: CRC errors before the SFD are ignored. Any packet must have a valid SFD in order to be
recognized by the 82598 (even bad packets).
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