Hello Qin: Please consider the message by Tero.
The ack is Mac-layer before upper layer processing and does not guarantee success in the stack. What we'd really want is suppress the MAC layer ack but not the 6P response. Another angle (for the sake of making sure we left no stone unturned). If we think transactionality is too difficult to achieve and that parent/child may lose sync: it is possible to avoid the issues with transactionality by using a bitmap to represent cells like LoRa does with frequencies. Step 1 the parent provides a list of cells (say 16) that it may allocate to that child in the future. The list may differ per child and may overlap with other children to enable to parent to temporarily give a cell to one child or another. Step 2 (runtime) the parent sends the bitmap of the cells, bit set if the cell is use child to parent. If this is sent regularly like a frame relay full status, things will eventually sync. What do you think? Pascal Le 8 mars 2016 à 22:34, Qin Wang <qinwang6...@yahoo.com<mailto:qinwang6...@yahoo.com>> a écrit : Hi Diego, I also have question regarding to the third message, i.e. Child acknowledge. In this case, the Child must accept the selected cells in the Parent's message if it received the message. Right? In another word, if the Parent knows the Child has received the message correctly, the Parent can be sure that the selected cells will be added/deleted into/from the Child's schedule. Since the MAC layer ACK can tell Parent the Child has received its message correctly, I think there is no need for the Child to send back the 6P layer Acknowledgement. Do I miss something? Thanks Qin On Friday, March 4, 2016 7:51 AM, Lijo Thomas <l...@cdac.in<mailto:l...@cdac.in>> wrote: Hi Diego, Do we really require 3 transactions for 6P operations as mentioned. The second transaction from the parent contains all the required information for the task. In case the 2nd packet is lost, the parent will schedule a RX link which will be unutilized for the time being and can be reallocated depending on the scheduling function. But if the 3rd transaction is lost, the client will allocate the TX link and will start transmitting packets. So can we avoid the ACK packet(3rd transaction) from the client, or is there any added benefit. Thanks & Regards, Lijo Thomas From: 6tisch [mailto:6tisch-boun...@ietf.org] On Behalf Of Prof. Diego Dujovne Sent: 03 March 2016 21:11 To: 6tisch@ietf.org<mailto:6tisch@ietf.org> Subject: [6tisch] 6P and Sf0 issue: Piggybacking data packet with IE confirmation Dear all, Given that there is parent preference in cell selection, a child-initiated transaction triggers a three-step exchange: 1- Child sends request to Parent with whitelist/blacklist of slotoffsets 2- Parent selects cells 3- Child acknowledges and finishes the transaction The main idea is to enable an optional Piggybacking of the IE on a data packet to reduce the number of transmitted packets, but there are latency concerns when the (data) traffic is low. Is it worth to enable this option given the added complexity? Regards, Diego Dujovne -- DIEGO DUJOVNE Académico Escuela de Ingeniería en Informática y Telecomunicaciones Facultad de Ingeniería UDP www.ingenieria.udp.cl<http://www.ingenieria.udp.cl/> (56 2) 676 8125 ------------------------------------------------------------------------------------------------------------------------------- [ C-DAC is on Social-Media too. Kindly follow us at: Facebook: https://www.facebook.com/CDACINDIA & Twitter: @cdacindia ] This e-mail is for the sole use of the intended recipient(s) and may contain confidential and privileged information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies and the original message. Any unauthorized review, use, disclosure, dissemination, forwarding, printing or copying of this email is strictly prohibited and appropriate legal action will be taken. ------------------------------------------------------------------------------------------------------------------------------- _______________________________________________ 6tisch mailing list 6tisch@ietf.org<mailto:6tisch@ietf.org> https://www.ietf.org/mailman/listinfo/6tisch _______________________________________________ 6tisch mailing list 6tisch@ietf.org<mailto:6tisch@ietf.org> https://www.ietf.org/mailman/listinfo/6tisch
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