82598EB Datasheet, PDF (418/596 Pages) Intel Corporation – Intel® 82598EB 10 Gigabit Ethernet Controller Datasheet

Intel^® 82598EB 10 GbE Controller - Components of a Sideband Interface
Figure 5-1. Sideband Interface
The sideband interface provides a mechanism by which the 82598 can be shared between the host and
the BMC. By providing this sideband interface, the BMC can communicate with the LAN without
requiring a dedicated Ethernet controller to do so.
The 82598 Eternet controller supports two sideband interfaces:
• SMBus
• NC-SI
The usable bandwidth for either direction is up to 400 Kb/s when using the SMBus interface and 100
Mb/s for the NC-SI interface.
Note that only one mode of sideband can be active at any given time. This configuration is done via an
EEPROM setting.
5.2
Components of a Sideband Interface
There are two components to a sideband interface:
• Physical Layer - The electrical layer that transfers data
• Logical Layer - the agreed upon protocol that is used for communications
The BMC and the the 82598 must be in alignment for both of these components. For example, the NC-
SI physical interface is based on the RMII interface. However, there are some differences at the physical
level (detailed in the NC-SI specification) and the protocol layer is completely different.
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