cbb@STC10.CTD.ORNL.GOV ("CBB") (04/19/88)
I see a potential problem with the use of Local Area VaX Clusters, LAVC, in a relatively large Local Broadcasting Network, say 300-400 nodes distributed in 4 or 5 DECnet Areas. LAVC nodes Multicast quite a bit in order to keep the LAV Cluster alive and, each cluster has its own unique Multicast (AB-00-04-01-xx-yy, where the last two bytes -yy are the Group code). In addition to the very large amount of Multicast traffic with Type field 60-07, an additional problem arises with the apparent requirement that the "Boot node" of the LAVC be at least a Level-1 (intra-Area) Router. A Broadcasting LAN gets in trouble with more than 32 Broadcasting Routers that can hear each other. I have read the appropriate literature in the "little orange books" to learn more about the Router requirement, without success. I have heard that you have to be a Level-1 Router in a LAVC, ONLY if your cluster has an Alias name, otherwise, all LAVC nodes can remain as end-nodes. The LAVC Multicasts are easily partioned in a multi-segment LAN environment by "Blocking" the unique LAVC Multicast at that segments LAN Bridge-100 (or any other smart bridge). The Routing layer Multicasts cannot be blocked because DECnet must stay alive. Can "we" get a discussion going about LAVC and the problems (or absence of problems) as I have indicated above??? Curt (is) E. Bemis, Jr. ******************************************************************** DECnet to: PHYVAX::BEMIS or 43508::BEMIS Bitnet to: cbb@ORNLSTC.BITnet; DDN to: cbb@stc10.ctd.ornl.gov ******************************************************************** ------ -------