Hi Behcet, This is a known feature of a route-over LoWPAN, we have been discussing that already a lot the last two years, and have converged on the current model. This model actually is not a multi-link subnet as such. Instead we have a single non-transitive (radio) link, where exact-match routing is used to overcome the fact that not all interfaces can hear each other at all times. We are referencing the Autoconf addressing model which makes similar assumptions about radio links.
On Aug 4, 2010, at 10:05 PM, Behcet Sarikaya wrote: > Hi Zach, > Prefix sharing assumption stated in Sec. 1.3 I think creates multi-link > subnet > issues described in RFC 4903 (not referenced in your ID) especially if > route-over is used. Similar concerns were raised in IETF 78 session. This was from a person in the audience not familiar with the 6LoWPAN WG if I remember right. > Of course if mesh-under is used then there is no problem but then there is > probably not much case for the Roll protocol. > > It seems that we have this dilemma of choosing between the two evils. > > I suggest that we avoid this problem by assigning a unique prefix for each > IPv6 > host and then freely use the roll protocol for route-over and use prefix > sharing > only if mesh-under is used. It is clear that you can not have it both ways. The suggestion you make below simply does not work with 6LoWPAN header compression, nor does it make sense with mobility. You may do that with a formal IPv6 network of course (see the Autoconf WG). Zach > > Regards, > > Behcet > > > > ----- Original Message ---- >> From: Zach Shelby <[email protected]> >> To: 6lowpan 6lowpan <[email protected]> >> Sent: Mon, August 2, 2010 4:53:16 PM >> Subject: [6lowpan] Fwd: New Version Notification for draft-ietf-6lowpan-nd-12 >> >> http://www.ietf.org/id/draft-ietf-6lowpan-nd-12.txt >> >> We have posted a new version of ND optimizations for LLNs. This closes all >> known tickets as per the WG meeting in Maastricht. In addition to fixing >> some >> nits and general editing, the substantive changes are: >> >> o Version field of ABRO moved after Length for 32-bit alignment of >> the reserved space (#90). >> >> o Several clarifications were made on router interaction, >> including a new section with router interaction examples (#91). >> >> o Temporary Neighbor Cache Entry created upon host sending NS+ARO, >> and SLLAO removed from multihop DAD NS/NA messages (#87). >> >> Begin forwarded message: >> >>> From: IETF I-D Submission Tool <[email protected]> >>> Date: August 3, 2010 12:46:30 AM GMT+03:00 >>> To: [email protected] >>> Cc: [email protected],[email protected] >>> Subject: New Version Notification for draft-ietf-6lowpan-nd-12 >>> >>> >>> A new version of I-D, draft-ietf-6lowpan-nd-12.txt has been successfully >> submitted by Zach Shelby and posted to the IETF repository. >>> >>> Filename: draft-ietf-6lowpan-nd >>> Revision: 12 >>> Title: Neighbor Discovery Optimization for Low-power and Lossy >> Networks >>> Creation_date: 2010-08-03 >>> WG ID: 6lowpan >>> Number_of_pages: 50 >>> >>> Abstract: >>> The IETF 6LoWPAN working group defines IPv6 for low-power and lossy >>> networks (LLNs) such as IEEE 802.15.4. This and other similar link >>> technologies have limited or no usage of multicast signaling due to >>> energy conservation. In addition, the wireless network may not >>> strictly follow traditional concept of IP subnets and IP links. IPv6 >>> Neighbor Discovery was not designed for non-transitive wireless >>> links. The traditional IPv6 link concept and heavy use of multicast >>> make the protocol inefficient and sometimes impractical in a low >>> power and lossy network. This document describes simple >>> optimizations to IPv6 Neighbor Discovery, addressing mechanisms and >>> duplicate address detection for 6LoWPAN and similar networks. >>> >>> >>> >>> The IETF Secretariat. >>> >>> >> >> -- >> Zach Shelby, Chief Nerd, Sensinode Ltd. >> http://zachshelby.org - My blog "On the Internet of Things" >> http://6lowpan.net - My book "6LoWPAN: The Wireless Embedded Internet" >> Mobile: +358 40 7796297 >> >> _______________________________________________ >> 6lowpan mailing list >> [email protected] >> https://www.ietf.org/mailman/listinfo/6lowpan >> > > > -- Zach Shelby, Chief Nerd, Sensinode Ltd. http://zachshelby.org - My blog "On the Internet of Things" http://6lowpan.net - My book "6LoWPAN: The Wireless Embedded Internet" Mobile: +358 40 7796297 _______________________________________________ 6lowpan mailing list [email protected] https://www.ietf.org/mailman/listinfo/6lowpan
