[6lowpan] Document in my opinion not ready for publication -- Re: WG last call on Routing Requirements draft

[JP Vasseur <[e-mail]>]

Dear all,

I do believe that this document is NOT ready for publication.

The fundamental issue has to do with what is called "6LoWPAN Routing"  
and this not just a terminology issue but an architectural and  
procedural issue.

In this document, several characteristics of the issues and challenges  
of routing in constrained and loosy environments are listed, nothing  
new to what is done in the ROLL Working Group. You mention that IP  
routing and what is referred to as Mesh-Under Routing can be used in  
such environment. So what is the aim of this document ?

1) Is it to provide routing requirement for L3 (route over) ?
2) Is it to provide routing requirement for L2 (mesh under) ?

If 1), then you may want to see with the ROLL WG whether some of the  
data could be used for this WG that is not already covered by the  
existing routing requirements documents.
If 2), what is the intent of the document since we do not rightly (at  
the IETF) intend to specify a L2 "routing" protocol for a specific  
media such as 802.15.4.

I could provide lengthy comments but that figure 2 summarizes most my  
concerns:

  Figure 1 shows the place of 6LoWPAN routing in the entire network
    stack.

     +-----------------------------+    +-----------------------------+
     |  Application Layer          |    |  Application Layer          |
     +-----------------------------+    +-----------------------------+
     |  Transport Layer (TCP/UDP)  |    |  Transport Layer (TCP/UDP)  |
     +-----------------------------+    +-----------------------------+
     |  Network Layer (IPv6)       |    |  Network       +---------+  |
     +-----------------------------+    |  Layer         | Routing |  |
     |  6LoWPAN       +---------+  |    |  (IPv6)        +---------+  |
     |  Adaptation    | Routing*|  |    +-----------------------------+
     |  Layer         +---------+  |    |  6LoWPAN Adaptation Layer   |
     +-----------------------------+    +-----------------------------+
     |  IEEE 802.15.4 (MAC)        |    |  IEEE 802.15.4 (MAC)        |
     +-----------------------------+    +-----------------------------+
     |  IEEE 802.15.4 (PHY)        |    |  IEEE 802.15.4 (PHY)        |
     +-----------------------------+    +-----------------------------+
     * Here, 'Routing' is not equivalent to IP routing,
       but includes the functionalities of path computation and
       forwarding under the IP layer.

         Figure 1: Mesh Under (left) and Route Over routing (right)

The right part is what we do at the IETF, in ROLL.
The left part looks like a new "architecture" to me, an adaptation  
layer performing routing. I guess that you in fact mean routing at the  
MAC layer, in which case, you may want to discuss it with IEEE.

Just another example:

"When a 6LoWPAN follows the Mesh Under configuration, the LoWPAN Edge
    Router (ER) is the only IPv6 router in the 6LoWPAN (see Figure 3).
    This means that the IPv6 link-local scope includes all nodes in the
    LoWPAN.  For this, a Mesh Under mechanism MUST be provided to  
support
    multi-hop transmission."
What is this normative "MUST" aimed at ?

Furthermore there are many other issues with the document but the  
statements above should hopefully help to show that the document  
should not be published. I know that this is informational, still we  
need to be cautious of what we publish as RFCs.

Thanks.

JP.

On Sep 2, 2009, at 2:21 AM, Geoff Mulligan wrote:

> Folks,
>  This note formally starts the WG Last Call for comments on
> draft-ietf-6lowpan-routing-requirements-04.txt, "Problem Statement and
> Requirements for 6LoWPAN Routing".
>
> The document can be found at:
> http://www.ietf.org/id/draft-ietf-6lowpan-routing-requirements-04.txt
>
> The document is intended to be submitted by this Working Group to the
> IESG for publication as an Informational Document.
>
> Please review the document carefully (one last time), and send your
> comments to the 6lowpan list.  Please also indicate in your response
> whether or not you think this document is ready to go to the IESG.
>
> This Last Call will end on Thursday 1 October 2009 at 2359 UTC.
>
>        Thanks,
>                Geoff & Carsten
>
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