Long before Sperry Corp became a part of Unisys Corp, it was promising 1100 mainframe users a full implementation of IBM’s SNA, and with the introduction of SNA/net, the product is finally ready. The product is a new program that runs on Unisys’ DCP family of communications processors and implements an SNA resource controller on the DCP. The DCP-based network backbones appear as IBM 37XX series – 3705, 3725, 3745 – processors to an IBM host, but provide better availability and greater functionality, Unisys claims, noting that network resources remain available when a host processor fails. The SNA/net software runs alongside the Telcon program in the DCP, and users can enter commands to modify SNA network components from the DCP Network Management System consoles using either IBM’s Network Communication Control Facility or Telcon NMS syntax. Management of the DCA network resources occurs autonomously. The new program consists of a core SNA/net base and two optional features. SNA/net base implements SNA PU type 5 functionality and when used alone, it enables the DCP to emulate a subarea node and domain in an SNA net, and it interfaces across the networks on a peer basis with VTAM in IBM hosts. The SNA/net DCA Crossover feature option enables interconnections between DCA and SNA destinations, supporting terminal-to-host cross-connections between the two logical networks. The SNA/net Network Packet Switching Interface option enables SNA/net nodes to use X25 networks for connection to 3274 cluster controllers and 37XX processors. SNA/net configuration files can be kept on disks attached to any DCP node for fast recovery and an automatic node switching feature enables workloads to be shifted when the system senses an irregularity in SNA/DCA operation; if a trunk line fails in the DCP backbone, alternate paths are established automatically without disruption of the session in progress. Network errors or unusual operating conditions are logged in a Telcon file to facilitate the identification, isolation, and diagnosis of network problems. SNA/net can also be attached to PU type 2 gateways from other network vendors, so that users of either IBM or Unisys applications can access additional resources. The five-year extended term plan licence for SNA/net base is $11,830 for DCP/10A and DCP/15 and $33,800 for larger DCPs. The DCA Crossover feature is $9,310 and $26,600, and the SNA/net NPSI feature is $3,605 and $10,300.
