MOM technology has become a key component of an enterprise application server which is usually deployed to process business logics. It has to cope with hundreds or even thousands of concurrent connections at the same time. In this end, the efficient and scalable connection management is required for large scale of clients' requests, and various network transport protocols must be taken into consideration when designing the network module of MOM. To facilitate the full support of PTP (Point-to-Point) and publish/subscribe messaging domains, and group communication service featured by MoIM-Message which is our MOM, this paper proposes three types of primitive messaging operations, "synchronous send", "synchronous receive", and "asynchronous receive", and describes the architecture of transport protocol adapter which can be extended to employee various transport protocols. Those functions are implemented into the Message Transport Layer of our MOM which is designed to have three hierarchical layers. Moreover "polling with multiple service thread model" that is applied into the socket adapter, is described to cope with the large number of concurrent clients' connections efficiently. To support mobile client platform, we ported the Client Runtime modules into IPaq PDA by utilizing PersonalJava.