Connection details ------------------ * Date: October 24, 2017 * Time: 8-9AM DST, 17:00 CEST: https://www.worldtimebuddy.com/?qm=1&lid=2988507,1816670,5391959,5128581&h=2988507&date=2017-10-24&sln=17-18 * Webex Link: https://cisco.webex.com/ciscosales/j.php?MTID=mda0658c049908cec459a2a0be9e0039b * Meeting number: 208 224 943 * Meeting password: d5bBrqTZ (35227789 from phones) * Join from a video conferencing system or application * Dial 208224943@cisco.webex.com * Join by phone * +1-866-432-9903 Call-in toll-free number (US/Canada) * +1-408-525-6800 Call-in toll number (US/Canada) * Access code: 208 224 943 Agenda ------ * [17:00] Administrivia [10min] o Note-Well, Scribes, Agenda Bashing o Status of drafts (WGLC / forthcoming WGLC) * [17:10] LPWAN Overview - WGLC status and updates [ 5min] * [17:15] Fragmentation comments (Carles) [10min] * [17:25] Update on SCHC fragmentation (Ana) [30min] * [17:55] AOB [ 0min] Minute takers ------------- * Ana Minaburo * Arunprabhu Kandasamy * Alexander Pelov * Dominique Barthel Attendees --------- * Alex Pelov * Ana minaburo * Arunprabhu Kandasamy * Dominique Barthel * Julien Catalano * Carles Gomez * Pascal Thubert * Laurent Toutain * Vincent Audebert * Ivaylo Petrov * Uday Davuluru * Tomas Lagos * Arumugam Paventhan * Jack Kozak * Juan Carlos Zuniga * Sergio López * Diego Dujovne * ? Mark Nowel -no audio- Past Attendees (previous meetings, for cc) --------- * Stephen Farrell * Ana minaburo * Laurent Toutain * Alex Pelov * Diego Dujovne * Juan-Carlos Zuniga * Julien Catalano * Sumankumar Panchal * Tomas Bolckmans * Carsten Bormann * Hannes Tschofenig * Carles Gomez * Diego Dujovne * Juan-Carlos Zuniga * Paul Duffy * A Paventhan * Friedhelm Rodermund * Arunprabhu Kandasamy * Pascal Thubert * Samian Kaur * Uday Davuluru * Alexander Pelov * Alper Yegin * Ana minaburo * Arunprabhu Kandasamy * Bob Heile * Pascal thubert * Laurent Toutain * Julien Catalano * Juan-Carlos Zuniga * Dominique Barthel * Russ Housley * Lorenzo Vangelista Agenda ------ * [17:00] Administrivia [10min] o Note-Well, Scribes, Agenda Bashing o Status of drafts (WGLC / forthcoming WGLC) * [17:10] LPWAN Overview - WGLC status and updates [ 5min] * [17:15] Fragmentation comments (Carles) [10min] * [17:25] Update on SCHC fragmentation (Ana) [30min] * [17:55] AOB [ 0min] Action Items from last time ---------------------------- * Laurent to split the FSM into two FSM (both for sender and receiver) and add to draft * Ana to change names of ACK/No ACK to shorter names * Arun to publish the change of the additional column for field lenght * Publish the version by next Tuesday (October 17th) * Chairs to wait for final IPR statements and continue with publishing LPWAN Overview document * The ML should discuss the Time Scale draft Minutes ------- * [17:00] Administrivia Alexander makes the announcement o Note-Well, Scribes, Agenda Bashing Agenda is agreed. Minutes of last interim meeting are approved. Most action items from last meeting are now done. Left to be done: sephard write-up of LPWN overview doc (expect by Thursday); discussion on ML of time scale. o Status of drafts (WGLC / forthcoming WGLC) * [17:10] LPWAN Overview - WGLC status and updates [ 5min] * [17:15] Fragmentation comments (Carles) [10min] Arrow to the right - downlink, to the left - uplink (puzzles the audience. Most would expect End-Device on the left, Infra on the right side of the picture). Description of pb: if ACK is lost in ACK Always mode on downlink fragmentation (Receiver is End-Device). In some LPWAN technologies, no downlink but right after an uplink. Sender will never be able to send ACK request unless the Receiver (End-Device) sends an uplink. Proposal is to allow the Receiver to re-send the ACK (uplink) on a timer expiration. Dominique: Link layer issue (e.g. Class A in LoRa). Do we need to solve link issues at IETF? Juan Carlos: would cause the receiver to drop the packet. We don't want that. Alex: since we expect a downlink, the End-Device wants to send an uplink. We can allow for taht. Pb is timer (???) Carles: pb is transmission is blocked. Could re-use same mechanism as in ACK on error mode just for the purpose of the downlink fragmentation. Laurent: Alex: Alex: what we are looking for is an ack to the ACK. Carles: a possibility could solve the pb for all but last window. Doesn't need to be perfect. Laurent: another solution is to copy bitmap. Alex: would like to avoid DL message in LPWAN. We could add another message Alex: Sender will infer that all fragments reached the Receiver because otherwise the Receiver would be requesting again and again for the missing fragments. (an implicit ack) * [17:44] Update on SCHC fragmentation (Ana) [30min] Present the changes done in -07 compared to previous one. Question: description of FSM in Annex or in main test? Pascal: usually in Annex, not normative. Ana: will do. Ana: better description of all-0 all-1, introducing the notion of "abort". The state machine takes time.. Ana: verify the description of the state machine With optimisation of bitmap, can encode all-1 abort Optimized bitmap: only one bit, set to 1 to mean all bits of the bitmap are 1s. set to 0 to mean frist fragment was lost (leftmost bit in bitmap is 0). Abort from sender to receiver: All-1 with no MIC and no payload => Abort If the receiver wants to abort - it uses ACK with FCN=1 and 1 byte = 1 (which differenciates with ACK) Slide 18: two separate Abort scenarios in the same drawing. The so-called ACK abort is not an ACK to the Abort immediately above. It's an abort sent by the Receiver, using an ACK message format. ANaa: MAX_ATTEMPTS to be used Pascal: why don't we acknowledge the Abort? Laurent: Abort is informational message. We're jsut being nice to the other end of the link. Should be able to do without the Abort message. Pascal: will want to move forward with sending packets, not lock waiting. Laurent: could echo the Abort. Pascal: can't wait for the ack. Case where Abort sent because link broken. Alex: * [17:55] AOB [ 0min] Running out of time. Pascal: need to book a few hours during the IETF meeting to review and sort out this stuff. Informal review on whiteboard. During the week, after the LPWAN WG meeting. Alex: why not during the next interim? Pascal: moving slowly. Will do much better progress during IETF meeting weeek. 5 volunteers Dominique, Juan Carlos, Carles, Alex, Pascal, Laurent Alex: yet, still make progress before that. Review docs, comment on ML. Next meeting in 2 weeks