Sorry for this late reply on this issue about the source address compression in multi-hop environment. After raising this issue in August, our research group has studied on the reporting of RERRs to the originators without a source address and a precursor list. The purpose of the research is to search a light weight RERR reporting scheme without putting a source address in the format and maintaining precursor lists on routing tables of every nodes.
If I say the conclusion first, the source address is at least not required in the 6lowpan format for reporting RERRs to the originators. In AODV, every intermediate node on a routing path keeps a precursor list on each routing entry for a destination. The setting up of the precursor list is done when processing RREQ and RREP. Thus, data packets do not need to have the originator address in AODV. What about 6lowpan? If a routing scheme of 6lowpan maintains precursor lists for routing as AODV does, data packets at least do not need to have the originator address. This issue could be handled in the routing documents. Currently, we have submitted a paper to a conference about the RERR reporting schemes. In the paper, we have proposed and evaluated several RERR reporting schemes including 1) unicasting a RERR back in one-hop only, 2) broadcasting backward a RERR in one-hop only, 3) broadcasting backward based on the routing table information, 4) using precursor lists, and 5) using the originator address if it is assumed to be added to the 6lowpan format document. In the preliminary performance evaluation result, (1) has shown the best result, and then (4) comes next in terms of the communication throughput. Also (1) showed the minimal implementation complexity. The detailed description of the schemes and performance results shall be shown shortly. -- Ki-Hyung Kim Associate Professor Division of Information and Computer Eng., Ajou University Wonchun-Dong, Yeongtong-Gu, Suwon, Korea 442-749 Tel: +82-31-219-2433, Cel: +82-17-760-2551, Fax: +82-31-219-1811 http://ilab.ajou.ac.kr/kkim86/index.htm > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf > Of gabriel montenegro > Sent: Thursday, October 13, 2005 10:02 AM > To: Samita Chakrabarti; [EMAIL PROTECTED]; itijibox- > [EMAIL PROTECTED] > Cc: [email protected] > Subject: Re: [6lowpan] format document issues > > Samita, > > --- Samita Chakrabarti <[EMAIL PROTECTED]> wrote: > > Thus, the format document can save one address field (for originator > source > > link-layer addr) by requiring the routing protocol to provide > information > > on originator address so that the intermediate node can setup reverse > route. > > Alternately, the intermediate node will have to do route-discovery for > the > > originator - that is certainly not effecient. > > Hope this clarifies the point. > > I *think* we're repeating each other. From my post: > > > But of course, routing protocols like AODV or LOAD don't use the M bit, > > they have > > originator and destination address fields within the RREQ. > > So we don't even have to require "the routing protocol to provide > information > on originator address so that the intermediate node can setup reverse > route." > The required info is already in the RREQ, right? > > -gabriel > > > _______________________________________________ > 6lowpan mailing list > [email protected] > https://www1.ietf.org/mailman/listinfo/6lowpan _______________________________________________ 6lowpan mailing list [email protected] https://www1.ietf.org/mailman/listinfo/6lowpan
