Re: [Roll] [roll] #128: Trickle multicast could be considered in other applications?

[Don Sturek <[e-mail]>]

Hi Esko,

I believe the reason that the ZIP specification provides for these host
only devices is:
1)  The RPL specification allows for RPL unaware leaf nodes.
2)   However, for the sake of MPL forwarding, I believe the RPL unaware
leaf nodes then do not receive MPL multicasts (which makes sense given
many of these devices are sleepy hosts which would likely not be
guaranteed to receive the transmission anyway).

The implied model used in ZIP is that sleepy host only devices are clients
which initiate actions (and would stay awake long enough to receive any
expected responses) but don't act as servers.

Don



On 8/26/13 7:57 AM, "Dijk, Esko" <[e-mail]> wrote:

>> I really wonder about these MPL-ignorant nodes which are part of an LLN
>>mesh (and therefore, I think), speak RPL.
>> Can you tell me more about them so that I am less skeptical about them
>>being mythical.
>
>Nodes that are fully MPL-ignorant could be rightfully called mythical, at
>least I haven't seen an implementation or specification of such nodes
>within an MPL-enabled LLN mesh. I'm just considering the option that
>there could be Hosts that are unaware of the forwarding protocol used,
>whose multicast traffic needs to be interfaced to the MPL domain. If that
>is an option that no implementer would ever go for anyway, we can safely
>stop this discussion I think.
>
>Background: A similar situation can be found in the ZigBee-IP
>specification, that defines "ZIP hosts" in the LLN mesh which do not
>implement the RPL routing protocol. These hosts send their IP packets to
>their parent "ZIP router" which further handles the packet using RPL.
>Sleepy Nodes are for example always ZIP hosts and never ZIP routers. In
>ZigBee-IP these Hosts are RPL-ignorant, but not MPL-ignorant.  My idea
>was that there could be another specification X that would define the
>Hosts also to be MPL-ignorant, for example to save energy in Sleepy Nodes.
>
>regards,
>Esko
>
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