In a computer network a logical duplex session between control points of adjacent network nodes is comprised of two physical half duplex sessions. Each half duplex session includes the send session of one node and the receive session of the adjacent node. In the event of a session failure at either node, the session from the other node is also deactivated so the nodes may begin recovery in phase with each other. Unique messages are exchanged between the adjacent nodes to distinguish new from old messages, such that the nodes are resynchronized only when new messages are present on each session.