Re: [6lowapp] [6lowpan] hardware trends, new vs. existing protocols [Re: 4861 usage in LLNs]

["Stuber, Michael" <[e-mail]>]

To be clear, I am not arguing that we should re-write every protocol,
and certainly not from scratch.  I think we need to be thoughtful about
how we apply these technologies to the problem space.  We need to be
efficient with all our resources.  The chips may get more powerful, but
the network (802.15.4) that we are targeting here will remain
constrained.  No doubt there will come a day when different network
technologies are applied in this space, but at that point I don't think
we're talking 6LoWPAN anymore.

-----Original Message-----
From: [e-mail] [mailto:[e-mail]] On
Behalf Of Kris Pister
Sent: Monday, November 09, 2009 10:12 PM
To: Stuber, Michael
Cc: 6lowpan; [e-mail]
Subject: Re: [6lowapp] [6lowpan] hardware trends, new vs. existing
protocols [Re: 4861 usage in LLNs]

 > Abandoning the installed base just goes to reinforce the idea  > that
IP isn't an appropriate technology for things.

Michael - I think that we have the same goal, but I disagree with that
statement.  I think that re-writing every protocol from discovery
through transport to applications, from scratch, is what reinforces the
idea that IP isn't an appropriate technology for things.

I realize that there are pressures from an installed base, but at this
point it's a tiny fraction of the overall potential.  If we let the 1%
installed base dictate the path for the next 99%, we should do our best
to ensure that it's the right path.

ksjp

Stuber, Michael wrote:
> Life may be getting better, but that doesn't mean we have the wrong 
> target.  Abandoning the installed base just goes to reinforce the idea

> that IP isn't an appropriate technology for things.  Qualifications 
> for parts in appliances, meters, and cars may take much longer than in

> other consumer electronics.  There are lots of products shipping today

> with
> 802.15.4 chips that do not match the (nicer) specs you outline below.
> If we want to enable IP everywhere, we must acknowledge that small 
> footprint parts are an important part of "everywhere."
>
> That said, I too am in favor of exploring optimized DHCP.  It would 
> provide the flexibility of living in an edge router, or being 
> centralized.  It is a well defined, characterized protocol.
>
> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On 
> Behalf Of Kris Pister
> Sent: Monday, November 09, 2009 6:53 PM
> To: Jonathan Hui
> Cc: Carsten Bormann; 6lowpan; [e-mail]
> Subject: [6lowpan] hardware trends, new vs. existing protocols [Re: 
> 4861 usage in LLNs]
>
> +1 in favor of using optimized DHCP if possible (no opinion on 'if
> possible'), rather than inventing something new.
>
> As I've shared with several people in private emails recently, it's 
> pretty clear that lowpan nodes are going to get more capable moving 
> forward, not less.  Why?  Radios don't scale down in area when you 
> scale
>
> CMOS processes.  Today's 15.4 single-chip nodes are made in 
> technologies
>
> that are several (maybe five?) generations behind the cutting edge.  
> This makes economic sense because the sales volumes don't support the 
> need for expensive mask sets yet.
> When there's a volume application, and someone puts a 5mm2 radio into 
> modern CMOS, it just doesn't make sense to put 48kB of rom/flash and 
> 10kB of RAM next to it.  You'll put hundreds of kB of rom/flash, and 
> many tens of kB of RAM, and the radio will still be by far the biggest

> thing on the chip.
>
> Even the 48k/10k node from the (very nice) 6lowapp bof presentation is

> not up to commercial standards - it's a five year old, expensive, 
> academic platform - great for it's time, but old.  Single-chip nodes 
> from Jennic, Freescale, etc. have ~200kB ROM/flash + 128kB RAM, a 
> 32bit processor, and they aren't made in cutting-edge processes yet
either.
> Life is just going to get better.  Let's try to find the smallest 
> optimized set of *existing* protocols that serve our needs, that run 
> on the existing new low-cost hardware (not the old workhorses). Let's 
> invent the absolute minimum of new "optimized" protocols, because it's

> not at all clear to me that we are optimizing the right things at this

> point.  The less we invent, the broader the set of applications and 
> applications programmers we address.
>
> ksjp
>
> Jonathan Hui wrote:
>   
>> On Nov 9, 2009, at 5:50 PM, Carsten Bormann wrote:
>>
>>     
>>> Again, entirely getting rid of a function is always the best 
>>> optimization.
>>> Can we do that for DAD?
>>>       
>> The *need* for DAD is the core question for me.  As specified within 
>> 6lowpan-nd now, IPv6 addresses are maintained using a centralized 
>> protocol.  That protocol looks and smells like DHCP - there's 
>> request/response, lease times, relays.  The whiteboard may also 
>> administratively assign addresses.  So in the end, it's not clear to 
>> me why we would need to *detect* duplicates when we essentially
>> *avoid* them from the beginning.
>>
>> I've voiced my comment several times over the past 1+ years and 
>> presented a draft that argues for the use of optimized DHCP in 
>> Dublin,
>>     
>
>   
>> so this is not new from my end.  The fact that the current 6lowpan-nd

>> document has evolved towards using DHCP-like mechanisms is not an 
>> accident.  But if what we do is DHCP-like, it would seem to make 
>> sense
>>     
>
>   
>> to utilize existing DHCP infrastructure rather than defining 
>> something
>>     
>
>   
>> new.
>>
>> --
>> Jonathan Hui
>>
>>     
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