OpenVMS Cluster (SCS) over DECnet? Over IP?
The OpenVMS Cluster environment operates over various network protocols, but the core of clustering uses the System Communications Services (SCS) protocols, and SCS-specific network datagrams. Direct (full) connectivity is assumed. An OpenVMS Cluster does not operate over DECnet, nor over IP. No SCS protocol routers are available. 15-11 Information on Networks and Clusters Many folks have suggested operating SCS over DECnet or IP over the years, but SCS is too far down in the layers, and any such project would entail a major or complete rewrite of SCS and of the DECnet or IP drivers. Further, the current DECnet and IP implementations have large tracts of code that operate at the application level, while SCS must operate in the rather more primitive contexts of the system and particularly the bootstrap-to get SCS to operate over a DECnet or IP connection would require relocating major portions of the DECnet or IP stack into the kernel.
