Xavi,
I agree LinkOptions-like field will bring more flexibility. (I say
LinkOptiions-like field because IEEE802.15.4e does not has the LinkOptions
anymore as Tero mentioned.)
I have a further question. Does it mean the LinkOption-like flag will
associated with a cell, instead of a transaction? In another word, the
LinkOptions-like flag will be part of 6P Cell Format with slotOffset and
channelOffset.
ThanksQin
On Wednesday, October 5, 2016 10:54 PM, Xavier Vilajosana
<[email protected]> wrote:
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.
ThanksQin
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.
--
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