Re: [6lowapp] HTTP and SIP

[Jonathan Hui <[e-mail]>]

On Oct 10, 2009, at 3:08 PM, Adam Dunkels wrote:

> Shidan wrote:
>> "request-response protocols like HTTP may require battery-operated,  
>> mostly sleeping nodes to be listening for requests much more  
>> frequently than their application processing requirements alone  
>> would need them to wake up."
>> "In addition, some of the applications may require optimizations in  
>> terms of bandwidth usage; for example, the usual data formats (both  
>> headers and body) are perceived to be too chatty for the 50-60 byte  
>> payloads possible in LoWPANs.  Their interpretation and generation  
>> may require too much code for the 8-bit and 16-bit processors  
>> dominating LoWPAN nodes."
>> None of these points seem evident to me.
>
> I very much agree with this. By so quickly dismissing the  
> opportunities with existing protocols such as HTTP and SIP, this  
> group may miss reaching widespread adoption of its protocols.

I also agree that we should not be so quick to come to conclusions  
without presentation of real empirical evidence.

> Both these arguments were frequently used in the past against IP for  
> resource-constrained systems, yet today we take IP for granted for  
> these systems despite the overheads of IP. We need to a pay price  
> for interoperability and flexibility, but we think it is worth it.

I'd be careful carrying the interoperability argument towards the  
upper layers.  IP was designed to be the narrow waist.  Today, that  
has evolved to UDP and TCP being the narrow waist [1].  We have far  
more flexibility and opportunity at the application layer than we do  
with TCP/UDP/IP and we should not be afraid to exploit that.  I do  
support the argument for evaluating existing protocols/architectures,  
but more because they are established, vetted, and widely understood,  
less so because we actually want to utilize the existing technical  
infrastructure that surrounds it.

[1] http://tools.ietf.org/html/draft-rosenberg-internet-waist-hourglass

--
Jonathan Hui