Data Sheet

System Manageability—Ethernet Controller I210
691
10.6.1.3 Data Transport
Since NC-SI is based upon the RMII transport layer, data is transferred in the form of Ethernet frames.
NC-SI defines two types of transmitted frames:
1. Control frames:
a. Configures and control the interface
b. Identified by a unique EtherType in their L2 header
2. Pass-through frames:
a. Actual LAN pass-through frames transferred from/to the BMC
b. Identified as not being a control frame
c. Attributed to a specific NC channel by their source MAC address (as configured in the NC by the
BMC)
10.6.1.3.1 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
BMC and can only be sent one at a time. Each command from the BMC is followed by a single response
from the NC (command-response flow), after which the BMC 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 BMC.
AEN functionality by the NC must be disabled by default, until activated by the BMC using the Enable
AEN commands.
In order to be considered a valid command, a 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 BMC
must set the channel ID inside the control frame to 0x45. The 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.
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.