Data Sheet

Ethernet Controller I210 —System Manageability
764
10.7.4 MCTP Over SMBus
The message format used for NC-SI over MCTP over SMBus is as follow:
10.7.4.1 SMBus Discovery Process
The I210 follows the discovery process described in section 6.5 of the MCTP SMBus/I2C Transport
Binding Specification (DSP0237). It indicates support for ASF in the SMBus getUID command (see
Section 10.5.8.5). It will respond to any SMBus command using the MCTP command code - so that the
bus owner knows the I210 supports MCTP.
Note: MCTP commands over SMBus are received from any master address and are answered to the
sender. There is no capturing of the bus owner address from any specific command.
10.7.4.2 MCTP Over SMBus Special Features
The I210 supports the following optional feature of MCTP when running over SMBus: Fairness
arbitration.
10.7.4.2.1 Fairness Arbitration
When sending MCTP messages over SMBus and when fairness arbitration is enabled (see
Section 6.7.3.3), the I210 should respect the fairness arbitration as defined in section 5.13 of DSP0237
when sending MCTP messages.
+0 +1 +2 +3
76543210765432107654321076543210
Destination Slave Address 0 Command Code = MCTP = 0Fh Byte count Source Slave Address
MCTP
Reserved
Header
version = 1
Destination endpoint ID Source endpoint ID
S
O
M
E
O
M
SEQ#
T
O
Tag
I
C
1
1. IC = 0
Message Type = 0x02/
0x03
NC-SI Command/Pass Through data
.....
NC-SI Command/Pass Through data
PEC
SMBus header/PEC
MCTP header
NC-SI header and payload