



DMSC Working Group                                                 X. Li
Internet-Draft                                             China Telecom
Intended status: Standards Track                         5 February 2026
Expires: 9 August 2026


    Multi-agent Collaboration Protocol Suite based on Agent Gateway
                       draft-li-dmsc-mcps-agw-00

Abstract

   This document specifies a Multi-agent Collaboration Protocol Suite
   based on Agent Gateway, which enables scalable, secure, and
   semantically driven collaboration among distributed agents across
   heterogeneous networks.  The protocol suite introduces Agent Gateways
   as control-plane entities responsible for agent registration,
   authentication, capability management, semantic routing and other
   functions, while preserving direct peer-to-peer semantic interactions
   among agents.

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Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.










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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Multi-Agent Collaboration Protocol Suite Overview . . . . . .   3
     4.1.  Agent Registration and Authorization Process  . . . . . .   5
     4.2.  Capability Digest and Synchronization Process . . . . . .   5
     4.3.  Semantic Resolution and Routing Process . . . . . . . . .   6
     4.4.  Task-based Multi-Agent Invocation Process . . . . . . . .   6
   5.  Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .   7
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   7.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   7
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   As multi-agent systems become increasingly distributed across
   heterogeneous networks and administrative domains, efficient, secure,
   and semantically meaningful collaboration among agents becomes a
   critical challenge.  Traditional service-oriented or message-based
   interaction models are insufficient to capture agent-level
   capabilities, dynamic task decomposition, and semantic intent-driven
   communication.

   This document specifies a Multi-agent Collaboration Protocol Suite
   based on Agent Gateway (AGW).  The suite defines a set of coordinated
   protocols that enable agent registration, authentication, capability
   synchronization, semantic routing, task-based invocation, and peer-
   to-peer semantic interaction.  The architecture leverages Agent
   Gateways as first-class network entities that mediate control, policy
   enforcement, and orchestration, while allowing agents to directly
   exchange semantic information once authorized.

   The protocol suite is aligned with the architectural principles of
   control/forwarding plane separation, least-privilege authorization,
   and session-scoped semantic communication.




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2.  Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119] .

3.  Terminology

   The following terms are defined in this draft:

   *  AGW: Agent Gateway.  A network-resident control and forwarding
      entity responsible for agent registration, local binding,
      capability management, semantic routing, and policy enforcement.

   *  Agent: An autonomous software entity capable of perception,
      planning, decision-making, and execution.

   *  Semantic Routing: The process of routing an Agent request based on
      the meaning or intent of the request, rather than solely on a pre-
      defined address or identifier.

   *  Central Auth: Central Authentication Service: A logically
      centralized authority that performs identity verification and
      authorization decisions for agents and gateways.

4.  Multi-Agent Collaboration Protocol Suite Overview

   The Multi-Agent Collaboration Protocol Suite based on Agent Gateway
   defines a set of coordinated protocols as shown in figure 1 that
   collectively enable secure agent onboarding, ,distributed capability
   visibility, semantic request resolution, peer-to-peer semantic
   interaction, and task-oriented multi-agent orchestration.  Rather
   than operating independently, these protocols are designed to be
   executed in a tightly coupled manner along the agent lifecycle and
   collaboration workflows.  The Agent Gateway (AGW) serves as the
   anchoring point for control-plane coordination, while semantic
   interactions are progressively delegated to agents once resolution
   and authorization are completed.

   The protocol suite consists of the following functional components::

   *  Agent Registration Protocol (ARP) and Agent Authentication and
      Authorization Protocol (AAAP), which jointly establish agent
      identity, trust, and operational scope.

   *  Capability Synchronization Protocol (CSP), which maintains
      distributed visibility of agent capability digest across gateways.




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   *  Semantic Resolution and Routing Protocol (SRRP), which enables
      semantic request discovery and routing across gateway domains.

   *  Task-based Invocation Protocol (TIP), which extends semantic
      routing to multi-agent task decomposition and orchestration.

   Each protocol operates at a specific phase of the collaboration
   lifecycle and may be invoked independently or in combination with
   others.  The following sections describe how these protocols are
   integrated into coherent operational flows.

 User        Agent A      AGW1          AGW3        Central Auth        AGW2        Agent B    Agent C
  |             |            |             |               |              |<--------------Register|
  |             |Register--->|             |               |              |<--Register|           |
  |             |            |--Auth Req------------------>|<---Auth Req--|           |           |     +-----------------------------+
  |             |            |<-----------------Auth Grant |--Auth Grant->|           |           |<----| Agent Registration process  |
  |             |<-Local Bind|             |               |              |           |           |     +-----------------------------+
  |             |            |             |               |              |--Local Bind (B,C)---->|
  |             |            |             |               |              |           |           |
  |             |            |             |               |              |           |           |     +-----------------------------+
  |             |            |<----------->|<-----Capa Digest and Sync -->|           |           |<----| Agent Gateway Interaction   |
  |             |            |             |               |              |           |           |     +-----------------------------+
  |             |            |             |               |              |           |           |
  |             |            |             |               |              |           |           |
  |             |            |             |               |              |           |           |
  | --Req-----> |-SemR Req-->|             |               |              |           |           |
  |             |            |             |               |              |           |           |
  |             |            |---SemR Req->|----------------------------->|           |           |
  |             |            |<------------|<------SemR Resp--------------|           |           |
  |             |<-SemR Resp |             |               |              |           |           |     +-----------------------------+
  |             |============================ Semantic Session========================|           |<----| Semantic Routing process    |
  |             |>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>|           |     +-----------------------------+
  |             |<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<|           |
  |             |            |             |               |              |           |           |
  |             |            |             |               |              |           |           |
  |             |            |             |               |              |           |           |
  |--Task Req-->|               +-----------------------------+           |           |           |
  |             | ---------->   | Semantic Routing process    |---------->|           |           |
  |             |               + ----------------------------+           |           |           |     +-----------------------------+
  |             |--------------------------------------Invoke------------------------------------>|<----|Task-based Invocation process|
  |             |<--------------------------------------Executing---------------------------------|     +-----------------------------+
  |             |            |             |               |              |           |           |

                           Figure 1 The overall sequence diagram of MCPS-AGW







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4.1.  Agent Registration and Authorization Process

   An agent MUST register with its locally attached Agent Gateway before
   participating in any collaboration.  This process is governed jointly
   by ARP and AAAP and establishes the agent’s identity, trust status,
   and capability binding.  Upon receiving a registration request, the
   Agent Gateway performs preliminary validation of the agent’s identity
   attributes and initial capability description, and creates a
   provisional local binding.  The gateway then initiates an
   authentication and authorization request to the Central
   Authentication Service, conveying the agent identity, gateway
   identity, and requested operational scope.

   The Central Authentication Service evaluates the request and returns
   an authorization grant or denial.  Upon successful authorization, the
   Agent Gateway finalizes the registration by assigning the agent a
   globally unique Agent Identifier and Capability Identifier(s).  An
   agent MUST NOT be considered active, discoverable, or invocable until
   this process completes successfully.  This combined registration and
   authorization procedure ensures that all subsequent semantic routing
   and task invocation operate on authenticated identities and policy-
   approved capability scopes.

4.2.  Capability Digest and Synchronization Process

   Each Agent Gateway maintains detailed capability information only for
   its locally registered agents.  Gateways do not synchronize full
   agent capability states with each other.  Instead, to support inter-
   gateway semantic resolution, gateways exchange capability digests
   using the Capability Synchronization Protocol (CSP).  A capability
   digest is a locally generated, abstract summary of available
   capabilities, designed solely to indicate what kinds of capabilities
   exist behind a gateway, rather than how those capabilities are
   internally implemented or executed by agents.The structure and
   semantics of capability digests are intentionally decoupled from
   agent-internal capability representations, allowing gateways to
   evolve local capability models without impacting inter-gateway
   interoperability.

   CSP distributes these capability digests incrementally.  An initial
   exchange establishes basic inter-gateway visibility, while subsequent
   updates convey only digest changes, such as newly advertised
   capabilities, capability updates, or withdrawals.  Digest updates are
   versioned and acknowledged to support consistency and conflict
   resolution.  Through this digest-based mechanism, gateways maintain a
   scalable and privacy-preserving view of distributed agent
   capabilities without requiring centralized directories or full
   capability replication.



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4.3.  Semantic Resolution and Routing Process

   When a user issues a request to an agent (e.g., Agent A), the agent
   abstracts the request into a semantic request and submits it to its
   locally attached Agent Gateway (AGW1).  This interaction is governed
   by the Semantic Resolution and Routing Protocol (SRRP).  Upon
   receiving the semantic request, AGW1 performs semantic parsing and
   normalization and consults its local capability directory.  If no
   matching capability identifier is found, AGW1 forwards the semantic
   request to a peer or upstream gateway (e.g., AGW3), which repeats the
   same resolution procedure.  If the request remains unresolved, it is
   further forwarded to another gateway (e.g., AGW2).

   When a gateway identifies a matching capability in its local
   directory, it generates a semantic resolution response containing the
   resolved capability identifier and the corresponding target agent
   information.  This response is propagated hop-by-hop back to the
   originating gateway and ultimately delivered to Agent A.

   Following successful resolution, Agent A and the target agent (e.g.,
   Agent B) directly establish a semantic session.  During the lifetime
   of this session, semantic data is exchanged directly between agents
   in a peer-to-peer manner, while gateways remain responsible for
   resolution, authorization scope enforcement, and security policy
   application during session establishment.

4.4.  Task-based Multi-Agent Invocation Process

   Task-based collaboration extends semantic resolution to scenarios
   requiring multiple agents and coordinated execution, as defined by
   the Task-based Invocation Protocol (TIP).  When a user initiates a
   task request, the request is delivered to Agent A, which performs
   semantic understanding of the task and decomposes it into one or more
   sub-tasks along with the required capabilities.  If Agent A does not
   possess task decomposition capabilities, its attached Agent Gateway
   MAY act as a proxy to analyze and decompose the task on behalf of the
   agent.

   For each sub-task, Agent A submits a semantic request to its local
   gateway, triggering the same multi-hop semantic resolution process
   defined by SRRP.  Unlike pure point-to-point semantic communication,
   gateways additionally apply task-level constraints, policy
   considerations, and capability selection logic to identify suitable
   target agents.

   The resolved results are returned to Agent A, which then directly
   invokes the selected agents and establishes the necessary semantic
   sessions for execution.  Through this mechanism, multiple agents can



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   be dynamically selected and coordinated to collaboratively execute
   complex tasks, while maintaining consistent authorization and
   security enforcement through gateway-mediated control-plane
   functions.

5.  Conclusion

   By explicitly separating control-plane functions from semantic
   interaction flows, and leveraging gateways as control-plane
   coordination points, the proposed protocol suite enables scalable and
   secure multi-agent collaboration without compromising agent autonomy.

6.  IANA Considerations

   TBD

7.  Acknowledgement

   TBD

8.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

Author's Address

   Xueting Li
   China Telecom
   Beiqijia Town, Changping District
   Beijing
   Beijing, 102209
   China
   Email: lixt2@foxmail.com















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