NCSI Protocol Support
Computers & ServersNetwork Controller Sideband Interface over MCTP/RMII
What is NCSI?
NC-SI (Network Controller Sideband Interface) is a DMTF standard that enables a baseboard management controller (BMC) to configure and manage network controllers (NICs) through a dedicated sideband channel. NC-SI can be transported over MCTP or directly over an RMII interface. The protocol handles NIC configuration commands such as enabling management traffic passthrough, setting MAC address filters, and querying link status — all without using the main network data path. Engineers debugging server network connectivity, BMC-to-NIC communication failures, and management network configuration need NC-SI decode to verify command-response exchanges and diagnose configuration errors.
NCSI Quick Reference
| type | Packet-based |
| signals | MCTP or RMII |
| features | BMC to NIC sideband management |
Acute Instruments Supporting NCSI
Ready to analyze this protocol?
See how Acute instruments capture and decode this protocol in real time. Request a demo or contact our team.
How to Analyze NCSI with Acute Instruments
Connect your Acute logic analyzer to the NC-SI transport interface (RMII signals between BMC and NIC, or MCTP transport signals).
Attach a ground lead to the target board's ground reference.
In the Acute software, select the NCSI protocol decoder and assign the interface signals to the correct input channels.
Configure the decoder for the transport type (RMII or MCTP).
Capture and view decoded NC-SI commands and responses showing command types, channel/package IDs, and payload data.