Xavi Vilajosana Guillen writes:
> We discussed this. We said to use NORMAL in order to support any type of
> packet in the minimal cell/s and not only EBs. From our discussions, I think
> that we all understood (at least is what I captured in the minimal text) that
> if the type is NORMAL we can also send EBs there and hence we discarded
> ADVERTISEMENT type.
I would disagree with that.
Note, that LinkType of ADVERTISING and NORMAL are local matters, they
are never transmitted over air, and there is not bits for them in the
IEs.
The section 8.2.19.3 MLME-SET-LINK.request of 802.15.4-2015 says:
LinkType Enumeration ADVERTISING, Set to ADVERTISING if the link
NORMAL is to be used to advertise the
network, otherwise set to NORMAL.
And:
If LinkType is set to ADVERTISE, the links may be used to send
Enhanced Beacon frames as the result of the MAC receiving a
MLME-BEACON.request.
Then in section "6.3.6 TSCH PAN formation" the text talks about the
"advertising device":
A TSCH PAN is formed when a device, referred to as an
advertising device, advertises the presence of the network by
sending Enhanced Beacon frames upon receipt of a
MLME-BEACON.request from a higher layer. In a TSCH PAN the
Enhanced Beacon frames contain the following IEs:
...
My understanding is that the fact that LinkType is set to ADVERTISING
indicates that specific link is used to send Enhanced Beacons out,
i.e. it is used to advertise the network compared to the other tx
links, which are not used to advertise network, but which are used for
normal traffic in the network.
The ADVERTISING link can also be used to send normal traffic on it,
and it may be used to send Enhanced Beacons after the higher layer
calls MLME-BEACON.request. I.e., MAC layer somehow needs to know which
link it should be using to send beacons out, and ADVERTISING LinkType
tells that to the MAC level. I also assume that the same link is also
used to send periodic Enhanced Beacons, altough I do not think that is
specified anywhere in the 802.15.4-2015.
I do not know what the MAC level does if none of the links are set to
ADVERTISING and higher layer calls MLME-BEACON.request. It might wait
for the next ADVERTISING link, and not finding them it would not send
the EB out ever.
So I think the LinkType for the minimal should be set as ADVERTISING,
so it can will be used to send EBs and other traffic out.
> A clarification of these will be really valuable now that I will
> proceed with the revision of minimal.
--
kivi...@iki.fi
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