82598EB Datasheet, PDF (422/596 Pages) Intel Corporation – Intel® 82598EB 10 Gigabit Ethernet Controller Datasheet

Intel^® 82598EB 10 GbE Controller - Pass-Through Multi-Port Modes
Note:
If the BMC uses a dedicated MAC address/VLAN tag, it should take care not to use L3/L4
decision filtering on top of it. Otherwise all the packets with the manageability MAC address/
VLAN tag filtered out at L3/L4 are forwarded to the host.
The following sections describe each of these stages in detail.
5.3.3.2.2 L2 Layer Filtering
Figure 5-2 shows the manageability L2 filtering. A packet passes successfully through L2 filtering if any
of the following conditions are met:
• It is a unicast packet and promiscuous unicast filtering is enabled from host.
• It is a multicast packet and promiscuous multicast filtering is enabled from host.
• It is a unicast packet and it matches one of the unicast MAC filters (host or manageability).
• It is a multicast packet and it matches one of the multicast filters.
• It is a broadcast packet. Note that in this case, the packet does not go through VLAN filtering
(VLAN filtering is assumed to match).
Promiscuous unicast mode - Promiscuous unicast mode can be set/cleared only by the LAN device
driver (not by the BMC), and it is usually used when the LAN device is used as a sniffer.
Promiscuous multicast mode - Promiscuous multicast is used in LAN devices that are used as a sniffer,
and is controlled only by the LAN device driver. This bit can also be used by a BMC requiring forwarding
of all multicasts.
Unicast filtering - The entire MAC address is checked against the 16 host unicast addresses and four
management unicast addresses (if enabled). The 16 host unicast addresses are controlled by the LAN
device driver (the BMC can not change them). The other four addresses are dedicated to management
functions and are only accessed by the BMC.
The BMC configures manageability unicast filtering via update manageability receive filtering (see
Section 5.3.10.1.6).
Multicast filtering - only 12 bits out of the packet's destination MAC address are compared against the
multicast entries. These entries can be configured only by the LAN device driver and cannot be
controlled by the BMC.
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