[Tinyos-devel] [Tinyos Core WG] TEP105: LowPowerListeningDutyCycles

[Andreas Koepke]

Philip Levis:
> 
> On May 19, 2008, at 11:31 AM, Andreas Koepke wrote:
> 
>> To settle this: we stick to the PacketAcknowledgements interface to 
>> tunnel the Reliable stuff through the AM layer.
>>
>> The original problem was the cancel optimization. I strongly dislike 
>> side effects of a cancel that returns FAIL. Side effects are evil.
>>
>> I think that cancel is an optimization -- it is not necessary to have 
>> the semantics "this packet will not arrive for sure". An "I don't care 
>> anymore that this packet arrives" seems much more natural to me.
> 
> I don't understand; the LPL cancel behavior I proposed don't have this 
> property. SUCCESS on cancel means "this packet will not arrive for 
> sure." FAIL means "this packet might arrive." That's no different than 
> any other packet, of course. However, you could cancel the LPL 
> transmissions. Since sendDone *never* means "this packet arrived for 
> sure," that works fine.
> 
> Phil

I guess you are right, and I have to get used to "tunneling". It would 
be nice to be able to distinguish the sendDone SUCCESS reasons: SUCCESS 
on cancel that returned FAIL vs. medium access SUCCESS indication...