Agent Gateway Protocol

Internet-Draft	agent-gw	March 2025
Muscariello, et al.	Expires 28 September 2025	[Page]

Abstract

This document specifies the Agent Gateway Protocol (AGP), a protocol designed to support real-time interactive AI applications at scale. AGP extends gRPC with publish-subscribe capabilities to enable efficient many-to-many communication patterns between AI agents. The protocol provides mechanisms for connection management, stream multiplexing, and flow control while maintaining compatibility with existing gRPC deployments.¶

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.¶

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.¶

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This Internet-Draft will expire on 28 September 2025.¶

2. Introduction

As AI systems become more sophisticated and interconnected, there is a growing need for protocols that can support real-time interactive applications at scale. The Agent Gateway Protocol (AGP) addresses this need by:¶

Extending gRPC with publish-subscribe patterns¶
Supporting bidirectional streaming between agents¶
Enabling efficient many-to-many communication¶
Maintaining backward compatibility with gRPC¶

2.1. Protocol Overview

AGP builds on gRPC's core features while adding:¶

Native support for pub/sub messaging patterns¶
Enhanced stream multiplexing capabilities¶
Real-time event notification system¶
Dynamic topic creation and management¶

3. Architecture

3.1. Protocol Layers

     +-------------------+
     |     Application   |
     +-------------------+
     |   AGP Services    |
     +-------------------+
     |     Pub/Sub       |
     +-------------------+
     |      gRPC         |
     +-------------------+
     |      HTTP/2       |
     +-------------------+

3.2. Core Components

Gateway Nodes: Handle routing and message distribution¶
Topics: Named channels for pub/sub communication¶
Streams: Bidirectional communication channels¶
Services: Application-specific RPC definitions¶

3.2.1. Gateway Nodes

Gateway Nodes are essential components of the Agent Gateway Protocol (AGP) architecture. They handle routing and message distribution between agents and manage the communication infrastructure. Gateway Nodes are composed of two main tables: the connection table and the subscription table.¶

3.2.1.1. Connection Table

The connection table maintains interfaces with neighboring nodes and local applications. It is responsible for:¶

Establishing and managing connections with other Gateway Nodes¶
Maintaining active connections with local applications¶
Handling connection setup, teardown, and error recovery¶

The connection table entries include:¶

Node ID: Unique identifier for the neighboring node or local application¶
Connection Status: Current status of the connection (e.g., active, inactive, error)¶
Connection Parameters: Details such as IP address, port, and security credentials¶

3.2.1.2. Subscription Table

The subscription table is used to map topic subscriptions to neighboring nodes. It manages the distribution of messages based on topic subscriptions and ensures efficient routing of pub/sub messages. The subscription table entries include:¶

Topic: The name of the topic to which the subscription applies¶
Subscriber Node IDs: List of node IDs that have subscribed to the topic¶
Subscription Status: Current status of the subscription (e.g., active, inactive)¶

The subscription table is responsible for:¶

Managing topic subscriptions from local applications and neighboring nodes¶
Routing messages to the appropriate subscribers based on topic subscriptions¶
Handling subscription updates, additions, and removals¶
Ensuring efficient and reliable message delivery¶

By maintaining these tables, Gateway Nodes facilitate seamless communication and message distribution in the AGP network, enabling real-time interactive AI applications at scale.¶

4. Security Considerations

The Agent Gateway Protocol (AGP) relies on the Messaging Layer Security (MLS) protocol to provide end-to-end security for group communications between agents.¶

4.1. MLS Integration

AGP uses MLS for the following security properties:¶

End-to-end encryption for all agent communications¶
Forward secrecy and post-compromise security¶
Group key management and membership changes¶
Scalable group messaging security¶

4.2. Authentication and Identity

Each agent MUST:¶

Maintain cryptographic identities compatible with MLS¶
Use certified credentials for initial authentication¶
Validate peer credentials during connection establishment¶
Support credential revocation and rotation¶

4.3. Group Security

MLS provides the following guarantees for agent groups:¶

Continuous group key updates¶
Secure member addition and removal¶
Protection against message forgery¶
Perfect forward secrecy for all messages¶

4.4. Operational Security

Implementations MUST:¶

Maintain secure key storage¶
Support MLS epoch advancement¶
Implement proper credential management¶
Monitor for security events¶
Support secure group state recovery¶

4.5. Privacy Considerations

AGP with MLS provides:¶

Metadata protection¶
Group membership privacy¶
Participant anonymity options¶
Traffic analysis resistance¶

4.6. Implementation Requirements

Implementations MUST NOT:¶

Use non-MLS encryption schemes¶
Support downgrades to less secure modes¶
Allow plaintext communication¶
Skip credential verification¶