[Tinyos-devel] Re: [Tinyos Core WG] time sync interfaces

[Philip Levis]

On Dec 12, 2007, at 11:59 AM, David Gay wrote:

> On Dec 12, 2007 11:09 AM, Philip Levis <pal at cs.stanford.edu> wrote:
>> PacketTimeSynch is a bit tougher, as it actually embeds a sender
>> timestamp in a packet. This has two basic issues:
>>
>>    2) How do nodes running different applications agree on the
>> timestamp precision?
>
> Why is this an issue? I might as well ask how different applications
> agree on the meaning/layout of packets (I am starting from an
> assumption that the presence of a timestamp is packet-specific rather
> than a general feature).
>

If a layer 3 protocol specification says "this packet has 32kHz, 16- 
bit timestamps in it," or some variant thereof, I agree. But if this  
is platform-specific rather than protocol-specific, there's an issue.  
Specifying it in a protocol might mean that some platforms cannot  
support certain protocols.

Phil