Subject: Re: [Roll] Questions while implementing RPL.

From: Alexandru Petrescu <[email-masked]>
Date: Tue, 23 Mar 2010 18:59:38 +0100

Hi JeongGil,

Someone is asking me about implementation of RPL.  Could you please
suggest whether the implementation you were about to write could somehow
be available to other researchers, PhDs, for evaluation.

Thanks in advance,

Alex

Le 25/01/2010 22:32, JeongGil Ko (John) a écrit :
> Hi.
>
> I am in the process of trying to implement RPL with respect to the
> rpl and metrics drafts. In the process, I had a few questions that
> was unclear in the writeups. Maybe someone can clear them up for me
> :)
>
> I will take ETX as an example. Let's say our goal is to find a route
> that 'minimizes' the aggregated ETX to the gateway (root of the
> DODAG). The flags of the routing metric/constraint header will
> indicate R=0, G=1, A=0x00, C=0, and O=0. When nodes send DIO messages
> will include this information for nodes that receive the DIO to parse
> and compute its own ETX for a specific path/parent. In this case, how
> would we indicate that 'minimizing' the ETX metric is our goal? On a
> receiving node's perspective it just received a DIO message saying
> that it is including a metric and the routing object type will be 7
> (recommended for ETX; pp. 20 of [draft-ietf-roll-routing-metrics]).
> As a result, the node will have different ETX values from different
> potential next hops and would have to select one from them as the
> preferred parent node. In the selection process, should it be already
> known that minimizing the ETX is the goal (OF) at the node in compile
> time? Or is there a way/scheme to infer that minimizing the ETX is
> the goal? To make nodes support different OFs dynamically in-run
> time, having a way to infer/notify the new OFs (goals) would be nice
> but I wonder if this is interesting. If everything is given in
> compile time, then we can simply make the nodes that do not recognize
> what to do with the OFs as leaf nodes (as stated in the rpl draft).
>
> Thanks.
>
> -John
>
> _______________________________________________ Roll mailing list
> [email-masked] https://www.ietf.org/mailman/listinfo/roll
>

---

From: "JeongGil Ko (John)" <[email-masked]>
Date: Tue, 23 Mar 2010 11:12:17 -0700

Hey Alex,

I didn't fully get your question but are you asking about the code release? The code is still in its pre-pre-pre alpha stage so I wouldn't say we can evaluate the performance of RPL yet with this code :) However, I was able to clear many things up in yesterday's meeting so I can get the speed up a bit now :) The goal, of course, is to make the code open in TinyOS 2.x. You can tell the person who asked about the implementation to directly contact me so that I can find someway to make him/her happy :)

Thanks!

-John

>> [email-masked] https://www.ietf.org/mailman/listinfo/roll

------
JeongGil Ko (John)
Ph.D. Student
Department of Computer Science
Johns Hopkins University
http://www.cs.jhu.edu/~jgko

---

From: Philip Levis <[email-masked]>
Date: Tue, 23 Mar 2010 11:14:04 -0700

> I didn't fully get your question but are you asking about the code release? The code is still in its pre-pre-pre alpha stage so I wouldn't say we can evaluate the performance of RPL yet with this c…

One side note -- TinyOS code is under a BSD license.

Phil

---

From: Alexandru Petrescu <[email-masked]>
Date: Tue, 23 Mar 2010 19:25:39 +0100

Le 23/03/2010 19:12, JeongGil Ko (John) a écrit :
> Hey Alex,
>
> I didn't fully get your question but are you asking about the code
> release? The code is still in its pre-pre-pre alpha stage so I
> wouldn't say we can evaluate the performance of RPL yet with this
> code :) However, I was able to clear many things up in yesterday's
> meeting so I can get the speed up a bit now :) The goal, of course,
> is to make the code open in TinyOS 2.x. You can tell the person who
> asked about the implementation to directly contact me so that I can
> find someway to make him/her happy :)

Sure, Cc'ed you in private, check private email.

Thanks for the reply,

Alex

>> Someone is asking me about implementation of RPL.  Could you
>> please suggest whether the implementation you were about to write
>> could somehow be available to other researchers, PhDs, for
>> evaluation.
>>
>> Thanks in advance,
>>
>> Alex
>>
>>> I am in the process of trying to implement RPL with respect to
>>> the rpl and metrics drafts. In the process, I had a few questions
>>> that was unclear in the writeups. Maybe someone can clear them up
>>> for me :)
>>>
>>> I will take ETX as an example. Let's say our goal is to find a
>>> route that 'minimizes' the aggregated ETX to the gateway (root of
>>> the DODAG). The flags of the routing metric/constraint header
>>> will indicate R=0, G=1, A=0x00, C=0, and O=0. When nodes send DIO
>>> messages will include this information for nodes that receive the
>>> DIO to parse and compute its own ETX for a specific path/parent.
>>> In this case, how would we indicate that 'minimizing' the ETX
>>> metric is our goal? On a receiving node's perspective it just
>>> received a DIO message saying that it is including a metric and
>>> the routing object type will be 7 (recommended for ETX; pp. 20 of
>>> [draft-ietf-roll-routing-metrics]). As a result, the node will
>>> have different ETX values from different potential next hops and
>>> would have to select one from them as the preferred parent node.
>>> In the selection process, should it be already known that
>>> minimizing the ETX is the goal (OF) at the node in compile time?
>>> Or is there a way/scheme to infer that minimizing the ETX is the
>>> goal? To make nodes support different OFs dynamically in-run
>>> time, having a way to infer/notify the new OFs (goals) would be
>>> nice but I wonder if this is interesting. If everything is given
>>> in compile time, then we can simply make the nodes that do not
>>> recognize what to do with the OFs as leaf nodes (as stated in the
>>> rpl draft).
>>>
>>> Thanks.
>>>
>>> -John
>>>
>>> _______________________________________________ Roll mailing
>>> list [email-masked] https://www.ietf.org/mailman/listinfo/roll
>>>
>>
>
> ------ JeongGil Ko (John) Ph.D. Student Department of Computer
> Science Johns Hopkins University http://www.cs.jhu.edu/~jgko
>
>