On Jun 12, 2006, at 2:10 PM, Adam wrote:
Thanks again, Philip. May I ask you another question: in genealogy of
tinyos protocols, what MAC protocols are used in each platform by
default?
Several people asked this question in the forum, but no one give an
accurate
answer.
The default TinyOS MAC has always been CSMA-based. There was no
proper name for the early MACs: they were just CSMA with randomized
backoff over a fixed interval. Initial backoff was usually larger
than contention backoff. So something like this:
tx() {
backoff in range A-B
}
backoff() {
if channel busy
backoff in range a-b
else
send packet
}
More recent mica2/CC1000 (in 1.x and 2.x) stacks have BMAC, which is
basically just a CSMA MAC that allows you to adjust constants, such
as your backoff intervals. BMAC also supports low power listening
(LPL), so low-power operation.
The CC2420 stacks (in 1.x and 2.x) also support some BMAC operations,
such as backoff interval control, but they do not support LPL.
Phil
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