MCTP

MCTP, or Management Component Transport Protocol, is a standard defined by the Distributed Management Task Force (DMTF) to provide a common transport layer for management components. It enables the reliable exchange of management messages—such as IPMI commands—across different physical media and system topologies, decoupling the management protocol from the transport.

Structure and addressing: MCTP defines a generic message framing and addressing model that identifies sending and receiving endpoints on a bus. It supports point-to-point and multi-drop configurations and uses bindings to map the logical messages to a specific transport. The protocol includes mechanisms for routing, addressing, and basic message integrity within a managed environment.

Bindings and transports: The protocol specifies bindings for several transports, including MCTP over I2C/SMBus, MCTP over PCIe, and MCTP over USB. These bindings carry MCTP messages between components such as baseboard management controllers and other management endpoints, with IPMI payloads often encapsulated within MCTP messages to preserve compatibility with existing management stacks.

Applications and scope: MCTP plays a central role in enterprise and server management architectures by providing a unified transport for management communications, enabling interoperability between components from different vendors. It is commonly used to transport IPMI messages and can integrate with other management frameworks as part of a broader modern datacenter management strategy.

Development and status: MCTP is maintained as a DMTF standard with revisions that address new transports and usage scenarios. It remains a foundational layer for management ecosystems that require cross-media message exchange between management endpoints.