Kerry, > No problem. I am not familiar with some of the standards you mention. > The problem comes in when these "last meters" protocols develop their own > proprietary data links. BACnet is in that camp currently with MS/TP, which > is one of several data links that it supports but the only one that does not > already have a "IPv6 over foo" RFC. As the larger vision is to transition > BACnet to native IPv6 in the future, I believe that draft-ietf-6man-6lobac > is a necessary step on that path since it is so widely deployed in commercial > building automation systems. It is about a factor of 10 less costly than > ethernet per driver, can cover long distances (1000-1200 m), and has a > sufficient data rate for the BAC application (up to 115.2 kpbs). > > That said, in conjunction with changes being made in parallel to the data > link (through a BACnet standard change proposal), I think that MS/TP can > fill a niche at the low end of wired data links (similar to the niche that > 6LoWPAN > fills in wireless) and will transport arbitrary IPv6 packets up to 1500 octets > in length (not including the IPHC dispatch header, and depending on link > MTU setting). To the extent that the standards you mention will exchange > their application data using standard IP transports, and the required data > rate is 115.2 kbps or less, then IPv6 over MS/TP should be a viable option.
thanks for your quick reply! KNX also refers to ANSI/ASHRAE 135 (http://www.knx.org/knx-standard/introduction/) so I can only hope that the work on MS/TP will also cover Europe. cheers, Ole -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
