[Tinyos-help] Questions on CTP functioning

[Pedro Almeida]

Hello, Phil;

Thanks once more for your help!
The TEP more or less explains all I need to know, even though the TEPs arent
exactly instruction manuals, so I only had those questions at the time.

Best regards,

Pedro

On 7/14/07, Philip Levis <pal at cs.stanford.edu> wrote:
>
> Pedro Almeida wrote:
> > Hello all;
> >
> > I have some doubts concerning the way CTP works:
> >
> > - when are CTP routing frames sent? and the LEEP frames?
> >
> > TEP 123 states: "The implementation sends routing beacons as LEEP
> > packets." What does this mean?
> >
> > but since "The implementation uses two mechanisms to estimate the
> > quality of a link: periodic LEEP [1] packets and data packets.", then
> > why do I notice that only after exactly 14 data messages exchanged do
> > I get correct payloads within the serial frames? it's as if the tree
> > is still being formed and until then, all i get is 0'es. If i reduce
> > the rate of data frames are being sent or if i increase the number of
> > nodes, it still requires exactly 14 frames (at least 14 frames on the
> > serial port) to give meaningful information. Are not the LEEP frames
> > used by default? How can i relate this to the behaviour i see in the
> > serial port. And the routing frames? are they also being exchanged by
> > default somewhere in the link layer?
> >
> > Thank you!
> >
> TEP 123 is not intended to document exactly how the implementation in
> net/ctp works; rather, it is intended to document how the protocol works
> and establish the requirements for interoperability. Therefore, 123 does
> not specify exactly how everything works, as that would make it
> impossible for protocol implementations to improve over time.
>
> The implementation in net/ctp currently uses a trickle timer for routing
> frames, resetting the timer when it hears a P bit or sets the P bit.
>
> Phil
>
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