Abstract: A recovery facility is provided for a system network architecture (SNA) communication system employed by a computer network. The recovery facility includes bringing up a backup processor upon detection of failure at an existing processor in the SNA network, wherein both the failing processor and the backup processor support a multi-link transmission group (TG). After bringing up the backup processor, a new communication link is activated between the backup processor and an existing SNA communications controller previously linked to the failing processor. Processing is performed to ensure that the SNA communications controller recognizes the new communication linked to the backup processor as a same subarea address, a same virtual route and a same TG number as the previous link to the failing processor, thereby accomplishing substitution of the backup processor for the failing processor in the SNA communications network without requiring restarting of the entire network.

Abstract: Continuous server service is provided during switching from a current server version to a new server version. After initiating switching, a socket associated with the current server version is left open so that the socket may continue to receive client calls. The socket is then associated with the new server version and client calls received during switching are buffered and subsequently processed by the new server version after switching is complete.