Re: [Roll] [roll] #105: trickle-mcast: how to determine scope of MPL domain

HI Esko,

The few LoWPAN implementations I have experience with, ignore the 
PANid.
Actually, this is great because when the original PANid node is removed 
the network continues to exist.
Contrary to Zigbee, where this is a problem and has led to 
standardization modifications.
So please do not start this discussion again.

So your implication (strange or not) is correct, and therfore I create 
these problems with unicast prefix based MC addresses.

Greetings,

Peter

Dijk, Esko schreef op 2012-11-15 10:46:
> Hi Peter, Michael,
>
> a question from your last 2 emails is the following:
> if multiple LoWPAN networks are assigned the same 802.15.4 channel
> (which is likely as Peter explained), would they not be assigned a
> different Pan-ID to logically separate them? So for the drawing that
> shows the 6 border routers case, there would be no mutual 
> connectivity
> between dissemination regions anyway.
>
> A related question is whether nodes from different LoWPANs are
> allowed, or not, to mutually communicate. (I could not find text on
> this in RFC 6282 and RFC 6775 (6lowpan-nd) ).
> If they are allowed that leads to some strange implications, for
> example a node in LoWPAN1 sends a link-local packet which is received
> by a node in LoWPAN2 even though it is on a different link (and
> different IPv6 prefix).
>
> I can put this question on the 6lowpan list, if needed.
>
> regards,
> Esko
>
>
> -----Original Message-----
> From: roll-bounces@ietf.org [mailto:roll-bounces@ietf.org] On Behalf
> Of peter van der Stok
> Sent: Wednesday 14 November 2012 9:38
> To: Michael Richardson
> Cc: roll@ietf.org
> Subject: Re: [Roll] [roll] #105: trickle-mcast: how to determine
> scope of MPL domain
>
> Hi Michael,
>
> sorry to be confusing.
>
> Again, this is not a real installation, just an example of what to
> expect.
> Surface area can be something like 100x30 square meters.
>
> I show 6 border routers coinciding with 6 disseminatiuon areas due to 
> a
> remark by Dario where he asked if it is possible that multiple
> disseminations areas can be present in one PAN.
> The answer is yes, because giving a border router to each 
> dissemination
> area (6) is quite expensive.
>
> Concerning the use of the same channel.
> When we have one PAN, one channel is used, that is clear.
> Having several PANs, it perspires that often only 2 channels of the
> ones specified by 802.15.4 provide good communication ([presence of
> 802.11, etc.).
>
> Several other additional organisational boundary conditions can 
> dictate
> the channel numbers.
>
> Hope this helps,
>
> peter
>
>
> Michael Richardson schreef op 2012-11-12 23:07:
>> splitting up your text to emphasize a few things:
>>
>>>>>>> "peter" == peter van der Stok <stokcons@xs4all.nl> writes:
>>     peter> The nodes in all networks use the same communication
>> channel.
>>
>> ...
>>
>>     peter> not forward the message.  In this network configuration
>> the
>>     peter> dissemination area is identical with a network.  From a
>> cost
>>     peter> perspective (less border routers) it is more realistic if
>> one
>>     peter> network covers the whole floor.
>>
>> But, in your diagram, you have 6 border routers?!?
>>
>> I don't understand why nodes in area1 and area2 should use the same
>> communication channel.
>
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