Hi Qin, the LinkOptions makes it more flexible for future uses (as it opens more options). I see the priority field for example also interesting.
I agree however that we use 5-extra bits per requested cell and that the timekeeping and priority fields are not in the scope as of today. Maybe even 8 if we leave some reserved bits as 15.4. thoughts? X 2016-10-05 17:27 GMT+02:00 Qin Wang <[email protected]>: > Hi Tero, > > Thank you for the update. > > According to my understanding, the flag used in 6P is trying to define the > communication direction of scheduled cell(s). So, I wonder if 2 bits flag > is enough. > > Thanks > Qin > > > On Wednesday, October 5, 2016 11:03 AM, Tero Kivinen <[email protected]> > wrote: > > > Qin Wang writes: > > In IEEE802.15.4e, LinkOptions is defined as follows. > > This was changed in the 802.15.4-2015, i.e., the MLME and he PIB no > longer specify bit numbers for those infrmation, they provide the same > information in separate parameters (TxLink, RxLink, SharedLink, > TimekeepngLink, PriorityLink), or spearate PIB entries (macTxType, > macRxType, macLinkTimekeeping and macPriorityType). > > The TSCH Slotframe and Link IE do define field called Link Options and > splits it to bits as follows: > > +---------+---------+-------------+-------------+----------+----------+ > | Bits: 0 | 1 | 2 | 3 | 4 | 5-7 | > +---------+---------+-------------+-------------+----------+----------+ > | TX Link | RX Link | Shared Link | Timekeeping | Priority | Reserved | > +---------+---------+-------------+-------------+----------+----------+ > Figure 7-54 --Link Options field format > > Note, that there is new bit for Priority in there too. And as normally > this is LSB first so care should be taken when written to the IETF > draft... > > > > Is it what you are going to use? Then, another way is to use two bits to > > express TX/RX/Share. I'm not sure which way is better than another. > > > Two bits is not enough to define all different link types. The text in > 802.15.4-2015 defining the bits is: > > The TX Link field shall be set to one if it is a TX link and > shall be set to zero otherwise. > > TX Shared links, indicated by the TX link field and Shared > Link field both set to one, may be used by a joining device to > send an Association Request command or higher layer message to > the advertising device. > > The RX Link field shall be set to one if the link is an RX > link and shall be set to zero otherwise. RX links are used by > a joining device to receive an Association Response command or > higher layer message from an advertising device. > > The Shared Link field shall be set to one if the link is a > shared link and shall be set to zero otherwise. A shared link > is one that uses contention to access the medium. > > A link may be used as both a TX shared link and RX link. > > The Timekeeping field shall be set to one if the link is to be > used for clock synchronization and shall be set to zero > otherwise. RX links shall have the Timekeeping field set to > one. > > The Priority field shall be set to one if the link is a > priority channel access, as defined in 6.2.5.2, and shall be > set to zero otherwise. > -- > [email protected] > > > >
_______________________________________________ 6tisch mailing list [email protected] https://www.ietf.org/mailman/listinfo/6tisch
