NC-SI
| Status | Published |
|---|---|
| Year started | 2010 |
| Organization | Distributed Management Task Force (DMTF) |
| Base standards | Platform Management Components Intercommunication (PMCI) |
| Domain | Out-of-band management |
| Abbreviation | NC-SI |
| Website |
www |
NC-SI ("Network Controller Sideband Interface") is an electrical interface and protocol defined by the Distributed Management Task Force (DMTF), which enables the connection of a Baseboard Management Controller (BMC) to a set of Network Interface Controller (NICs) in server computer systems for the purpose of enabling out-of-band remote manageability.
Hardware interface
The NC-SI interface is based on the RMII interface with some modifications allowing connection of multiple network controllers to a single BMC. It contains the following signals:
| Signal | Description |
|---|---|
| REF_CLK | A 50 MHz clock reference for receive, transmit, and control interface |
| CRS_DV | Carrier Sense/Receive Data Valid for traffic sent from one of the NCs |
| RXD[1:0] | Receive Data (from NC to BMC) |
| TX_EN | Transmit Enable - Data Valid for traffic sent from the BMC |
| TXD[1:0] | Transmit Data (from BMC to NC) |
| RX_ER | Receive Error |
| ARB_IN | Hardware Arbitration ring - input |
| ARB_OUT | Hardware Arbitration ring - output |
Traffic types
NC-SI traffic can be either pass-through or control traffic, with both traffic types in form of Ethernet frames. Pass-through traffic consists of data exchanged between the BMC and the network via the NC-SI interface. Control traffic includes frames used to configure and control of the NC-SI interface and is identified by an EtherType of 0x88F8.
There are three types of control packets:
- Commands, sent from the BMC to one of the NCs.
- Responses, sent by the NCs as results of the commands.
- AENs (Asynchronous Events Notifications), sent asynchronously by the NCs, equivalent to interrupts.