Re: [Roll] definition of "RPL Domain"

[Don Sturek <[e-mail]>]

Hi Mukul,

I guess my view on this is the opposite of yours.  I would like to see
host-only devices not need to know anything about RPL.  Here is why:
1)  Code savings.   Removing RPL from these host only devices would allow
for deployment on smaller footprint devices
2)  Battery operated devices.   Some host only devices are deployed on
non-mains powered devices.  It would be nice for these devices to not have
to listen for any RPL control messages yet still support transmission into
a RPL routing domain.

Don



On 11/16/11 10:07 AM, "Mukul Goyal" <[e-mail]> wrote:

>Hi Sebastien
>
>First, I would like to clarify that the need to define "RPL domain" arose
>because draft-ietf-6man-rpl-option and draft-ietf-6man-rpl-routing-header
>were using the term. Now, these drafts use the term "RPL instance" and
>hence there is no real need to define the term "RPL domain" any more. I
>will change draft-ietf-roll-p2p-measurement so that all references to
>"RPL domain" are changed to "RPL Instance".
>
>Now returning to the question whether hosts should be considered part of
>the RPL Instance, the benefit of doing so is that there is no need to use
>IP-in-IP tunneling when a host sends out some data. If a host is not
>considered part of the RPL Instance, its default RPL router is obliged to
>use IP-in-IP tunneling to forward the packet further. IP-in-IP tunneling
>means an extra IPv6 header and thus less space for payload if you want to
>avoid fragmentation. Also, if the packet is traveling along a DAG, the
>encapsulation/decapsulation needs to be done at every hop, which sounds
>fairly heavy duty processing to me.
>
>So, I would like to explore if there is a way we could consider hosts to
>be a part of the RPL Instance.
>
>Regards,
>Mukul
>
>>On what ground would you assume that a non-RPL aware host connected to a
>>RPL-router (in this case I would call it a border router) is in a/the
>>RPL Domain?
>
>> From what I've seen in the drafts, the term "RPL Domain"'s primary
>>purpose it to differentiate the limits of "RPL-aware" nodes for IP
>>traffic that needs to transit to or from a set of RPL-aware hosts (for
>>example, to define where to add/remove the RPL IPv6 Hop-by-Hop Option if
>>used).
>
>>To me, this interpretation of RPL Domain is thus only useful in a local
>>context and not to meant to designate one or more bounded set of nodes.
>>That's the role of DODAGs and Instances.
>
>>Best Regards,
>
>>Sébastien Dawans
>
>On 11/16/2011 02:20 PM, Mukul Goyal wrote:
>> So, the revised doubts are as follows:
>>
>> 1. It is clear that RPL routers are within an RPL domain but what about
>>the RPL-unaware IPv6 hosts attached to an RPL router? I would imagine
>>that such hosts are also within an RPL domain.
>>
>> 2. Is an RPL domain same as an RPL instance? Or is an RPL domain a set
>>of RPL instances in the LLN? Can multiple RPL domains exist within an
>>LLN? Or is it that an RPL domain is same as an LLN using RPL as a
>>routing protocol?
>>
>> THanks
>> Mukul
>>
>> ----- Original Message -----
>> From: "Mukul Goyal"<[e-mail]>
>> To: "Thomas Heide Clausen"<[e-mail]>
>> Cc: "roll"<[e-mail]>
>> Sent: Wednesday, November 16, 2011 7:15:59 AM
>> Subject: Re: [Roll] definition of "RPL Domain"
>>
>>    
>>> Now that we are at it: what is an RPL host? Or rather, why is this
>>>even a conceivable thing to define? Afaik, RPL is a routing protocol,
>>>and as such should concern only routers - not hosts?
>>>      
>> My bad. By RPL host, I actually meant an RPL leaf node. I think this
>>term "RPL host" was in use at one point in time but I cant find a
>>reference to it in current spec.
>>
>> THanks
>> Mukul
>>
>>
>>
>> ----- Original Message -----
>> From: "Thomas Heide Clausen"<[e-mail]>
>> To: "Mukul Goyal"<[e-mail]>
>> Cc: "JP Vasseur"<[e-mail]>, "roll"<[e-mail]>
>> Sent: Wednesday, November 16, 2011 6:25:31 AM
>> Subject: Re: [Roll] definition of "RPL Domain"
>>
>> Now that we are at it: what is an RPL host? Or rather, why is this even
>>a conceivable thing to define? Afaik, RPL is a routing protocol, and as
>>such should concern only routers - not hosts?
>>
>> I worry if this is inventing an entire ecosystem which "pretends to be
>>just like the Internet, except it is not", as it needs entirely new
>>stacks, protocols, translators/gateways everywhere, and with no real
>>traces of IP as we know it remaining?
>>
>>    
>
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