Abstract: A system enabled for reliable and ordered data communication between two sets of nodes with atomic multi-point delivery and multi-point transmission, for example, extending TCP/IP is described hereon. The transmission control protocol (TCP/IP) is intended for reliable host-to-host communication [RFC 793]. The invention extends TCP's notion of host-to-host communication to symmetric group-to-group communication maintaining TCP specifications for data traffic between the groups. The current definition of, two endpoints of a TCP connection is extended to two groups of endpoints, communicating over the connection. End-points of a connection terminate at group nodes. When multiple nodes must be delivered with data, the delivery is performed atomically. Of data originating multiple nodes, optionally, a single data instance is transmitted. Each endpoint is comprised of a receiveHead and a sendHead operating independently.