[Tinyos-devel] Current status of the message buffer discussion

[Philip Levis]

On May 22, 2009, at 5:03 AM, Jan Hauer wrote:

> I agree with a lot you say. But while it is less overhead to transfer
> a contiguous packet from MCU to radio -- e.g. for the CC2420 you'd
> only need a single call to TXFIFO.write() -- splitting this in two
> operations shouldn't be much extra cost (currently not many radio
> drivers seem to use DMA for this, anyway). Especially if it saves you
> a call to format() that would need to propagate through the entire
> stack before.
>
> The packet layout/encapsulation discussion is to some degree coupled
> with how protocol components in TinyOS should interact, what the
> communication abstractions should be. It seems that AM as the current
> link-layer abstraction is not flexible enough and having the basic
> address-free Send/Receive interfaces on the layers above might also
> not be enough. But this is a topic that should be discussed by core +
> net2 group. To still get a feeling about how the interfaces
> (conceptually) might look like for accessing/passing the proposed
> message buffer abstractions, Vlado and Miklos agreed to come up with a
> use case, for which we would then explain how it is implemented with
> the different proposals.

I'll try to communicate some of the discussion to net2 on the net2  
call today. Om has assembled a sub-group within net2 to collaborate  
with core by giving feedback and insights on design requirements,  
tradeoffs, and considerations.

Phil