[Tinyos-devel] net2 goals/timeline for 2.1.1

[Philip Levis]

On Jun 12, 2009, at 12:08 PM, Stephen Dawson-Haggerty wrote:

> The major issue for core is the frame format.  The 6lowpan standard
> when used over 802.15.4 requires the 6lowpan payload to start
> immediately following the 802.15.4 frame header; the first byte is an
> IANA assigned dispatch value.
>
> This dispatch value is the same as the "network" field when I-frames
> are enabled, and so it is possible to have a radio stack which
> supports both Active Messages and other network protocols.  This is
> pretty much the same as the dispatching of packets base on the
> ethernet header in other systems-- IP and non-IP protocols can
> coexist.
>
> Conceptually, the layering would be (for AM)
> --------------------------
> | 802.15.4 | network (6LOWPAN_NALP) | AM  | ...
> --------------------------
>
> What is needed is an interface to intercept the non-NALP network
> values and feed them into blip, and an interface to allow blip to send
> packets with its own (arbitrary) network ids.

Well, as I said, it's important to remain radio-chip independent. We  
want to think about blip working on all kinds of link layers, not  
just 802.15.4. So while we definitely have to handle that case, the  
solution should not be constrained to that case.

Would it make sense for <RadioChip>ActiveMessageP to have

provides interface Receive as NotAMReceive;

then have a MessageC which exports this?

My one major concern is detecting at compile-time whether you're  
expecting non-AM packets but the link layer doesn't support them. I  
suppose this could be handled by whether the above interface exists.

Phil