[Tinyos-host-mote-wg] Re: TinyOS 2.0 host-mote working group

[Gilman Tolle]

(discussion moved to tinyos-host-mote-wg)

So, let's list some problems. 

The only way for a host to discover whether a mote is attached is to
send a data message to a (hopefully) unused AM type, and listen for
the ACK.

All messages passing over the serial link are framed in the radio's
link header. Therefore, communication between a PC and a mote is
impossible without a priori knowledge of the radio installed on the
mote.

The mote radio and the serial link have mismatched speeds, which
causes packet loss under heavy contention for the serial link.

Some motes may send multiple different types of packets over the
serial link. For example, consider a TOSBase that sends and receives
802.15.4 data packets as different from a hypothetical 15.4 packet
sniffing application that sends 15.4 beacons, data packets, and acks.

The types of messages that should flow from a host to a mote are
different from those that travel between motes. For example, a message
that configures the addressing information or changes the radio state
of the attached mote.

Gil

On Apr 5, 2005 9:49 PM, Philip Levis <pal at eecs.berkeley.edu> wrote:
> On Apr 5, 2005, at 3:07 PM, Karen Weeks wrote:
> 
> >> Should we be using PPP as is? and is the framing protocol really the
> >> source of the problems that arise when connecting a mote to a pc?
> >
> > I think if we do use PPP, we should use it as is (although I think
> > leaving out some of the configuration features still counts as 'as
> > is', although the IETF woud disagree on interoperability terms).
> > While I don't know whether or not the framing protocol is to blame for
> > some of the mote/PC communication issues, standardising and
> > robustifying this interface is still A Good Thing (TM).  While it may
> > not fix things, it can give us greater visibility into how / why /
> > when things go wrong (maybe it could help eliminate the hostmote
> > protocol as the source of problems), and give us a path to attempt to
> > reset in the worst case.
> 
> What are the problems with connecting motes to a PC? I very rarely see
> bad packets (unless my environment is messed up) and very rarely lose
> packets. Of course, I understand that in many cases we'd like to change
> "very rarely lose" to "never lose." I guess I read "source of the
> problems that arise" and I want to know exactly what those problems
> are.
> 
> One problem I think everyone agrees on is the dependency on the TOS_Msg
> structure of a mote platform. What are the others? I think this gets to
> Cory's statement of "what constitutes success?"
> 
> 
> Phil
> 
> -------
> 
> "We shall not cease from exploration
> And the end of all our exploring
> Will be to arrive where we started
> And know the place for the first time."
> 
> - T. S. Eliot,  'Little Gidding'
> 
>