China Telecom Beijing University of Posts and Telecommunications Zhongguancun Laboratory AsiaInfo Technologies (China) Inc 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 key entities responsible for agent registration, authentication, capability management and other functions, while preserving direct peer-to-peer semantic interactions among agents.