82598EB Datasheet, PDF (484/596 Pages) Intel Corporation – Intel® 82598EB 10 Gigabit Ethernet Controller Datasheet

Intel^® 82598EB 10 GbE Controller - Overview
NC-SI defines two types of frames transmitted on the NC-SI interface:
1. Control frames:
a. Frames used to configure and control the interface.
b. Control frames are identified by a unique EtherType in their L2 header.
2. Pass-through frames:
a. The actual LAN pass-through frames transferred from/to the MC.
b. Pass-through frames are identified as not being a control frame.
c. Pass-through frames are attributed to a specific NC channel by their source MAC address (as
configured in the NC by the MC).
5.4.1.3.1 Control Frames
NC-SI control frames are identified by a unique NC-SI EtherType (0x88F8).
Control frames are used in a single-threaded operation, meaning commands are generated only by the
MC and can only be sent one at a time. Each command from the MC is followed by a single response
from the NC (command-response flow), after which the MC is allowed to send a new command.
The only exception to the command-response flow is the Asynchronous Event Notification (AEN). These
control frames are sent unsolicited from the NC to the MC.
Note: AEN functionality by the NC must be disabled by default, until activated by the MC using the
Enable AEN commands.
In order to be considered a valid command, the control frame must:
1. Comply with the NC-SI header format.
2. Be targeted to a valid channel in the package via the Package ID and Channel ID fields.
For example, to target a NC channel with package ID of 0x2 and internal channel ID of 0x5, The MC
must set the channel ID inside the control frame to 0x45.
Note: Channel ID is composed of three bits of package ID and five bits of internal channel ID.
3. Contain a correct payload checksum (if used).
4. Meet any other condition defined by NC-SI.
Note: There are also commands (such as select package) targeted to the package as a whole.
These commands must use an internal channel ID of 0x1F.
For more details, refer to the NC-SI specification.
5.4.1.3.2 NC-SI Frames Receive Flow
Figure 5-12 shows the overall flow for frames received on the NC from the MC.
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