NC-SI, abbreviated from network controller sideband interface, is an electrical interface and protocol defined by the Distributed Management Task Force (DMTF). The NC-SI enables the connection of a baseboard management controller (BMC) to one or more network interface controllers (NICs) in a server computer system for the purpose of enabling out-of-band system management. This allows the BMC to use the network connections of the NIC ports for the management traffic, in addition to the regular host traffic.
The NC-SI defines a control communication protocol between the BMC and NICs. The NC-SI is supported over several transports and physical interfaces.
简而言之，BMC有本身的网卡，NIC也是独立的网卡，通过一种连接协议让BMC这块网卡共享NIC线路传输数据。如果你能通过SSH连接到你的服务器，而同时你的BMC支持共享连接方式，那么恭喜你，你不用去机房也能远程连BMC了，甚至不用多插网线。
二、ipmitool是什么
ipmitool - utility for controlling IPMI-enabled devices
This program lets you manage Intelligent Platform Management Interface (IPMI) functions of
either the local system, via a kernel device driver, or a remote system, using IPMI v1.5
and IPMI v2.0. These functions include printing FRU information, LAN configuration, sensor
readings, and remote chassis power control.
IPMI management of a local system interface requires a compatible IPMI kernel driver to be
installed and configured. On Linux this driver is called OpenIPMI and it is included in
standard distributions. On Solaris this driver is called BMC and is included in Solaris
10. Management of a remote station requires the IPMI-over-LAN interface to be enabled and
configured. Depending on the particular requirements of each system it may be possible to
enable the LAN interface using ipmitool over the system interface.
