A communication protocol service in support of TCP based communication is modified to improve the operational efficiency of a server for a particular type of client-server application. The service is modified to support connection pools and connection groups within the connection pools, to enable connections with clients to be grouped and share a common file descriptor. The service is provided with an API to allow an application server to create the connection pools, connection groups and connections. The API also include receive and send services adapted to support the connection pool and connection group architecture, and to allow explicit acknowledgement of received transmissions under control of the application server. Further, in various embodiments, the buffering architecture of the service, as well as acknowledgement of request packets by the service are also modified.