Kris, Archrock was at the many many meetings that this document was presented over the past several years so they had many opportunities to make comments and did. The document is in LC.
Carl -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Kris Pister Sent: Wednesday, September 02, 2009 1:59 PM To: Geoff Mulligan Cc: 6lowpan Subject: Re: [6lowpan] WG last call on Use-Case draft document Eunah et al. I would be much happier with this document if star-connected nodes were the exception rather than the rule. Can we add some more links in there so the reader will get used to the idea of meshes rather than trees? Most people who have done commercial deployments will tell you that stars and trees are lethal for reliability. As far as RFD vs. FFD goes, does anyone even make an RFD? I'd also recommend an update to the "typical characteristics" in section 1. * Under "low power" you're mixing RF transmit power ("up to 1000mW") and radio power consumption ("between 10 mW and 20mW"). Also, there's exactly one 802.15.4 radio that falls into that range (the DN2510). The rest are all substantially higher. * The specs on memory and processor horsepower are from the golden age of academic wsn research, and are almost a decade out of date. Look at what Freescale, Atmel, Jennic, etc. are shipping in volume. They are 32-bit cores (typically ARM7) running at tens of MHz, with tens of kB of RAM. Section 3: * Connectivity: I disagree with the association of "sleeping mode" with "intermittent" connectivity. There are many L2 protocols that allow tradeoffs between duty cycle and link BW. I would not call those nodes that sleep >99% of the time intermittent - they just have lower effective bit rate links. In particular, reading down in 4.1.1 the description of industrial monitoring connectivity as "always on for crucial processes, otherwise intermittent" does not fit with what's happening in the real world, and would tend to mislead someone not well versed in the field. * "several traffic patterns may be overused in LoWPANs" - overused? * "primordial" - I've seen networks like this, but I don't think that's what you really mean 4.1.2 Figures 4 and 5 You confuse "mesh" with "multi-hop" in your captions. Figure 5 has no meshing at all. maybe keep the caption, and put in some real meshing? Same thing for figure 6 and 7. I strongly disagree with the statement in 4.2.1 that this would work with a star topology, or a hierarchical star. 4.2.1 * "The network configuration and forwarding/routing tables are changed only in the case of node failure". Huh? Forwarding/routing tables will be updated *regularly* in a network like this due to connectivity changes. The RF environment is not static, even on a 'static' structure like a bridge, and even with line of sight. Every piece of metal on a bridge looks like a mirror to RF, and all of the mirrors move a little. Overall, I'm concerned that this document does not feel to me like it embraces the practical knowledge from real world deployments from *many* different companies using *many* different protocols. Did you talk to Arch Rock, Control 4, Dust, Ember, Emerson, Streetline, ...? We're not in the academic phase anymore - we've actually got lots of real-world data now, and much of it seems to be at odds with what's in this document. ksjp Geoff Mulligan wrote: > Folks, > This note formally starts the WG Last Call for comments on > draft-ietf-6lowpan-usecases-03.txt, "Design and Application Spaces for 6LoWPANs". > > The document can be found at: > http://www.ietf.org/id/draft-ietf-6lowpan-usecases-03.txt > > The document is intended to be submitted by this Working Group to the > IESG for publication as an Informational Document. > > Please review the document carefully (one last time), and send your > comments to the 6lowpan list. Please also indicate in your response > whether or not you think this document is ready to go to the IESG. > > This Last Call will end on Thursday 1 October 2009 at 2359 UTC. > > Thanks, > Geoff & Carsten > > _______________________________________________ > 6lowpan mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/6lowpan > _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
