NC-SI, abbreviated from network controller sideband interface, is an electrical interface and protocol defined by the
Distributed Management Task Force
Distributed Management Task Force (DMTF) is a 501(c)(6) nonprofit industry standards organization that creates open manageability standards spanning diverse emerging and traditional IT infrastructures including cloud, virtualization, network, s ...
(DMTF). The NC-SI enables the connection of a
baseboard management controller
The Intelligent Platform Management Interface (IPMI) is a set of computer interface specifications for an autonomous computer subsystem that provides management and monitoring capabilities independently of the host system's CPU, firmware (BIOS or ...
(BMC) to one or more
network interface controller
A network interface controller (NIC, also known as a network interface card, network adapter, LAN adapter or physical network interface, and by similar terms) is a computer hardware component that connects a computer to a computer network.
Ear ...
s (NICs) in a server computer system for the purpose of enabling
out-of-band
Out-of-band activity is activity outside a defined telecommunications frequency band, or, metaphorically, outside of any primary communication channel. Protection from falsing is among its purposes.
Examples General usage
* Out-of-band agreement ...
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.
[OCP NIC 3.0 Specification 1.00 (PDF) in Open Compute Project Server/Mez]
/ref>
The NC-SI defines a control communication protocol between the BMC and NICs. The NC-SI is supported over several transports and physical interfaces.
Hardware interface
The RMII-based transport (RBT) interface defined by NC-SI is based on the Media Independent Interface, RMII specification with some modifications that allow connection of multiple network controllers to a single BMC. The NC-SI can also operate over a variety of other electrical interfaces, including SMBus The System Management Bus (abbreviated to SMBus or SMB) is a single-ended simple two-wire bus for the purpose of lightweight communication. Most commonly it is found in computer motherboards for communication with the power source for ON/OFF instru ...
and PCI Express when used over the Management Component Transport Protocol
Management Component Transport Protocol (MCTP) is a protocol designed by the Distributed Management Task Force (DMTF) to support communications between different intelligent hardware components that make up a platform management subsystem, provid ...
(MCTP).
The table below sums up the signals comprising the RBT interface.
Traffic types
The NC-SI defines two fundamental types of traffic, pass-through and control traffic. Pass-through traffic consists of data exchanged between the BMC and the network via the NC-SI interface. Control traffic is used to inventory and configure aspects of NIC operation and control the NC-SI interface.
Control traffic is broken down into three sub-types:
* Commands, sent from the BMC to one of the NICs
* Responses, sent by the NICs as results of the commands
* Asynchronous event notifications (AENs), sent asynchronously by the NICs and equivalently to interrupts, upon the occurrence of the specified event
When the NC-SI is used over RBT, standard Ethernet framing is used for all traffic types. Control traffic is identified by using an EtherType
EtherType is a two-Octet (computing), octet field in an Ethernet frame. It is used to indicate which Communications protocol, protocol is Encapsulation (networking), encapsulated in the payload of the frame and is used at the receiving end by th ...
of 0x88F8. When the NC-SI is used in conjunction with MCTP, MCTP provides the packetization methodology and traffic type identification.
See also
* Management Component Transport Protocol
Management Component Transport Protocol (MCTP) is a protocol designed by the Distributed Management Task Force (DMTF) to support communications between different intelligent hardware components that make up a platform management subsystem, provid ...
(MCTP)
* Platform Management Components Intercommunication
Distributed Management Task Force (DMTF) is a 501(c)(6) nonprofit industry standards organization that creates open manageability standards spanning diverse emerging and traditional IT infrastructures including cloud, virtualization, network, s ...
(PMCI)
References
External links
DMTF Homepage
NC-SI Specification rev 1.1.0
NC-SI over MCTP Binding Specification rev 1.2.2
{{DEFAULTSORT:Nc-Si
DMTF standards
Out-of-band management