Geoff, I agree that "use case" is a better term than architecture, especially considering the historical issues that Carsten has raised. But I also believe that the incorporation of very small devices into a 6lowpan "use case" is important to the adoption of 6lowpan. Cost is also important consideration for 6lowpan adoption. An extra $0.01 in cost imposed by 6lowpan, has a potential $100 million annual impact to the adoption of wireless communications to the micro controller industry at today's production rates.
Ron -----Original Message----- From: Geoff Mulligan [mailto:[EMAIL PROTECTED] Sent: Friday, November 03, 2006 12:36 AM To: Ron Strich Cc: '6lowpan' Subject: Re: [6lowpan] 6lowpan Architecture Questions Ron, These are excellent points. I would like to hear from other on the list about the idea of supporting extremely small devices (4K) (smaller than the extremely small devices that we have been targeting (32K)). I would not like to choose to miss a potential market segment (potentially large market segment), but is it reasonable to got after a 4k device which probably could not possibly ever accept a 1280 byte (minimum size ipv6) packet. I think question 2 is going to be critical as we move to the next phase of this working group. Hopefully we will finish the format document and start on rechartering. One of the top areas that I think we need to look at is the idea of utilizing Manet and how the design will impact 6lowpan (memory, power, other costs). And whether or not we choose to use the manet approach and protocols, should we down select to a single protocol or some small set and if so what is the criteria for this selection. Please consider what criteria you think we should use to evaluate the available mesh protocols. While the IETF doesn't appear to embrace architecture docs, it is critical for us to agree on some set of use-cases so that we can focus our efforts on providing real solutions. So again, please consider for our rechartering and new work items, should we generate a set of use-cases? What is the format for this? Should we support extremely small devices? And finally what criteria should we use to determine the selection/evaluation of mesh routing protocols (which probably begs for a use-case analysis.) Folks, please start to participate in these discussions. It is only with your input that we will have a successful working group and will create a standard that is useful in the market. geoff On Fri, 2006-10-27 at 09:07 -0500, Ron Strich wrote: > 1. Many sensor and control devices will be too small to support a full > mesh/ip adaptation implementation. Some of these devices may be as small as > 4K of flash and 100s of bytes of RAM and may only be used in a point to > point (P2P), simple star, or very simple mesh implementation (please see the > attached pdf drawing). Incorporation of these very small devices, I > believe, is important to the broad adoption of 6lowpan. > > Should we consider how to support these extremely limited devices? Should > we make it easy for these simple protocol implementations at this level to > adapt to 6lowpan? If we want to include these small devices, should we > consider a more constrained design (limited payload, P2P/star only) that > would simplify the adaptation layer? > > 2. How will the group evaluate what mesh, P2P or star protocols should be > supported? As David pointed out, we may not be allowing for future > capabilities in the current structure of the adaptation layer should we want > to support multiple types of L2 protocols. > > 3. Related to the pending mesh protocol evaluation, is the evaluation of any > functionality related to the "cost" of those technical choices in terms of > power, code size, complexity, RAM, instructions executed, etc? > > 4. As was mentioned on the list a while ago, neither the Problem Statement > nor the Format documents discuss the overall 6LoWPAN architecture. As we > move forward with our next working group items, shouldn't we create a > document to describe the high level architecture which might well encompass > the criteria for evaluation of the protocols and costs mentioned above? > > Ron Strich > Mobile: 228.369.4332 > _______________________________________________ > 6lowpan mailing list > [email protected] > https://www1.ietf.org/mailman/listinfo/6lowpan _______________________________________________ 6lowpan mailing list [email protected] https://www1.ietf.org/mailman/listinfo/6lowpan
