BUDDENBERGRA@A.ISI.EDU.UUCP (06/12/87)
Folks on the net might be interested in a sitrep on our work with a survivable LAN for shipboard use... Start with an IEEE-802.5 (or ISO 8802/5) token ring. Add a second, contra-rotating ring for redundancy. If the first ring fails, traffic shifts to the second. If a double cut or loos of node occurs, each last surviving node wraps data from one ring to another and, voila, self-healing. As ring is damaged further, partitioning occurs (cut up a starfish, get multiple starfish), but it keeps on trucking. The SAFENET philosophy is to specify a superset of the 802.5 standard that gains the survivability necessary for operational tactical purposes on ships (to replace a number of point-to-point links). Objective is to eventually influence the industry standard adequately so that no separate MilStd is required. The initial objective of providing service to computers within the ship appears within reach fairly quickly. The goal is something quotable by October. Other problems are cropping up that, in my estimation, will be nowhere near a standards solution this fall. Leading is the inability of the ISO stack to provide 'real-time' service. Since most of the issues are at higher layers, they are beyond the scope of a group formed to work on a specific LAN. Ditto for network management and multi-level security. This week we worked over revision 0 which was a 'very first draft'. Three subcommittees got their components 1) down in writing and 2) all in the same manuscript for the first time, so things were a bit rough. But things seem to be moving along; I'll try and post another report after the next meeting in July. [All above is personal appraisal and opinion] Rex Buddenberg -------
braden@BRADEN.ISI.EDU (Bob Braden) (06/12/87)
Other problems are cropping up that, in my estimation, will be
nowhere near a standards solution this fall. Leading is the
inability of the ISO stack to provide 'real-time' service.
Can you explain/amplify that last comment?? What do you mean by
"'real-time' service"?
Thanks.
Bob Braden