Subject: Re: [Roll] RPL Discussion yesterday

From: "Anders Brandt" <[email-masked]>
Date: Thu, 1 Oct 2009 13:53:32 +0200

Hi

Just wanted to confirm the experience of a productive meeting.

After having been somewhat worried over a lot of features still
solving just one third of the identified requirements, I am now
more confident that we will actually be able to bring ideas and
solutions together for a full solution.

Thus, I just want to remind us all on the most prominent topics
to address just after the 5 topics listed by JP:

A) P2MP
   1) The meeting clarified that nodes MUST NOT be assigned new
      address if radio phenomena cause nodes to re-attach to a
      parent in a neighbor sub-DAG.

   2) The consequence of A1) is that a router may potentially
      have to hold a number of explicit /128 entries that are
      to be propagated all the way to the top.

B) P2P
   1) In home and building application spaces, there is a need
      for reactive network re-discovery, so that a controller
      may re-gain access to an actuator within (significantly
      less than) a second.
      Example: If a light module is unreachable from the most
      recent set of parents, the triggle timer based system
      of advertisements may cause the module to wait potentially
      for hours before announcing its presence to a new parent.

   2) One way to address B1) is to introduce an AODV-style
      discovery mechanism. This mechanism should be limited to
      4 or 5 repeater hops but not tied to DAG topologies.

   3) Source routing may be the best candidate for traversing
      the mesh along paths not following - or allowed by - 
      the DAG.

   4) Due to B3) the AODV principles may have to be adjusted to
      determine source routed paths via up 4 hops - of course
      using the same routing stack which is already part of RPL;
      But now with a direction bit for nodes not having to swap
      the routing stack in order to return a response the same
      way from where they just got a request.

With JP's optimism I guess this is done 4 weeks from now?

Cheers,
  Anders

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
JP Vasseur
Sent: 1. oktober 2009 07:59
To: roll WG
Subject: [Roll] RPL Discussion yesterday

Dear all,

We had an extremely production and fruitful interim meeting yesterday,
and there was a strong consensus on several key simplifications of RPL,
we're most definitely on the right track. Since several implementations
are on the way, we agreed to produce a new revision of RPL extremely
quickly and the author team is already working on them.

Basically

1) Major editorial clean-up: eliminate redundant text, the protocol
overview section should be more high level.
2) RPL specifies how to build a (colored) DAG where the color simply
reflect a set of constraints and metrics determined by the OCP. The
decisions on whether a node should join more than one DAG is
administratively determined and will be discussed in applicability
statement.
3) The decision was also made to clarify the use of the sequence number
+ make complex operation of DAG merging/.... optional
4) We will keep unchanged the NA-DAO model that allows to support nodes
with extremely limited memory (thanks to source routing) and nodes that
can store routing tables. Various clarifications are required (see the
minutes to be posted soon).
5) Add the FSM to the document.

Time Line ... within two weeks. Challenging but doable considering how
productive the WG is ;-)

Thanks.

JP.
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---

From: JP Vasseur <[email-masked]>
Date: Thu, 1 Oct 2009 19:08:50 +0200

Dear all,

First of all, I would like to re-iterate the fruitful consensus that  
we reached yesterday on many items.
The authors' team had another discussion with the objective to propose  
a plan. Here it is:

Rev-03 (early next week) will be purely editorial. The Protocol  
Overview will be shortened, redundant text will be removed and the  
document will be slightly reorganized for the sake of clarity.

Rev-04 is the revision that should lead us to a fairly stabilize  
protocol version explicitly covering the items 2), 3) 4) and 5) below.
More specifically, we will send out an email to propose several  
options for 3) early next week. PLEASE provide feed-back, comments and  
suggestions.

The goal is to have rev-04 out for Oct 19.

Rev-05 will cover security.

Thanks to all of you, we continue to progress really well.

JP.

The authors
On Oct 1, 2009, at 7:59 AM, JP Vasseur wrote:

> Dear all,
>
> We had an extremely production and fruitful interim meeting  
> yesterday, and there was a strong consensus on several key  
> simplifications of RPL, we're most definitely on the right track.  
> Since several implementations are on the way, we agreed to produce a  
> new revision of RPL extremely quickly and the author team is already  
> working on them.
>
> Basically
>
> 3) The decision was also made to clarify the use of the sequence  
> number + make complex operation of DAG merging/.... optional
> 4) We will keep unchanged the NA-DAO model that allows to support  
> nodes with extremely limited memory (thanks to source routing) and  
> nodes that can store routing tables. Various clarifications are  
> required (see the minutes to be posted soon).
> Time Line ... within two weeks. Challenging but doable considering  
> how productive the WG is ;-)
>
> Thanks.
>
> JP.