Re: [6lowapp] HTTP and SIP

[Adam Dunkels <[e-mail]>]

Don Sturek wrote:
> .5 seconds for one hop and 2 seconds for 4 hops are really not acceptable
> for many applications.
> 
> We should of course investigate using existing protocols.   However it does
> not seem likely that full HTTP and XML deployed over devices like IEEE
> 802.15.4 with very small packet sizes will scale very well  (certainly, for
> any application expecting to do home or building controls, those latencies
> don't work).  Ideally, we should find something that allows for full
> HTTP/etc. while enabling constrained devices to operate with a solution that
> can be expanded/compressed.

I agree with this, and that's also why I think the 6lowapp initiative is 
important.

As a sidenote, though: the 0.5 seconds and 2 seconds are not latencies, 
but completion time. Latency about 0.3s per hop in this case, which is 
due to the power-saving radio mechanism we use, which switches the radio 
off for 99% of the time, while waking up twice per second. So the 
HTTP/TCP does not incur the significant part of the latency in this case.

/adam
-- 
Adam Dunkels <[e-mail]>se>, [phone]
http://twitter.com/adunk | http://www.sics.se/~adam/