Re: [manet] LOADng-06

[Ulrich Herberg <[e-mail]>]

Bo,

On Oct 23, 2012, at 4:38, Bo Berry <[e-mail]> wrote:

> 
> On Oct 22, 2012, at 10:49 PM, Ulrich Herberg wrote:
> 
>> Hi Bo,
>> 
>> On Mon, Oct 22, 2012 at 6:39 PM, Bo Berry <[e-mail]> wrote:
>> Hi Alex
>> 
>> For those of us that have not have the opportunity to follow
>> the Loadng discussions, could you please describe the similarities
>> and the unique differences of Loadng relative to Dymo.  I'm aware
>> of the discussions about lousy nets and manets, but less between
>> the two protocols.
>> 
>> I think this would help everyone on the WG understand the benefits.
>> 
>> 
>> I agree with that, and it is a fair question to ask. Let me try to list a few differences, others may chime in with more. 
>> 
>> First the commonalities:
>> - Both are reactive protocols, based on AODV, with the intended status of "Proposed Standard" (AODV is "Experimental"). The MANET charter lists that the WG has to come up with a std. track reactive protocol. Essentially, in a reactive protocol, routes are requested "on-demand" (i.e. when there is data traffic and no route exists for the destination of the data packet). Therefore, you will see similar message types in both protocols (Route Requests, Route Replies, and Route Errors), and essentially the same basic mechanism.
>> - Both are applicable to MANETs (see also below for your next question), and both support RFC5444. LOADng is decoupling the mechanism from the message format; RFC5444 is mapped to the mechanism, but other message formats could easily be specified (e.g., with a more compressed message format for extremely limited links in terms of bandwidth).
>> 
>> Now some differences:
>> - Most importantly: LOADng has achieved what DYMO failed to do: to gather broad industrial support from several large companies, several large-scale deployments with several thousands of nodes, LOADng has an updated MIB document, and documented interoperability test of at least four recent implementations.
>> - Part of the reason, I believe, is that the writing style is very different. LOADng has a more algorithmic way of writing. That's immediate to see when you compare section 5.3 of DYMO with section 12 of LOADng. It is, IMO, much harder to implement DYMO. The goal for LOADng was to make it so straight forward to implement that an undergrad student could take the spec, spend a few days implementing it and have a reasonable and interoperable implementation. I have implemented LOADng in one day, based on the specification.
>> - There are multiple optional features in DYMO that have deliberately not been included in LOADng (expanding ring multicasts, intermediate RREPs, precursor lists etc). The reason was the following: in an experimental protocol (AODV) it is fine to have many options, in order to explore whether they are useful. We have that experience now with AODV. For some of the options, such as iRREP, it has not been shown over the last decade that they are of general use. In some cases, they may be beneficial, but not in general. Also, they make it very hard to provide end-to-end security. LOADng kept the mantra of a small, slim, and efficient protocol. Having many options makes it hard to assure interoperable devices out of the box, in particular if there is no negotiation of capabilities.
>> Moreover, reactive protocols are often used in cases where memory is an extremely scarce resource, and where proactive protocols cannot be used. That makes a slim design preferable, IMO, for such protocols.
>> - LOADng may be used in other layers as L3, e.g. as mesh-under protocol.
>> - LOADng supports optimized broadcasting mechanisms such as MPR flooding
>> - There is no Route Reply ACK in DYMO; this is part of LOADng to verify bidirectionality of links; as in wireless channels, links are rarely symmetric. 
>> 
>> 
>> Looking at the Tools page, the draft was first submitted October 24, 2011,
>> draft-clausen-lln-loadng-00.  The title was, "The LLN On-demand Ad hoc
>> Distance-vector Routing Protocol - Next Generation (LOADng)."  The
>> abstract included the statement "The protocol is derived
>> from AODV and extended for use in LLNs".
>> 
>> Then in the July 14, 2012 version, draft-clausen-lln-loadng-05, the
>> line "The protocol is derived from AODV (RFC3561) and extended for
>> use in LLNs." was removed.  This version also supported RFC 5444.
>> 
>> The draft posted tonight, October 22, 2012, draft-clausen-lln-loadng-06,
>> for the most part changes "Low power and Lossy Networks (LLN)"
>> references to "Mobile Ad hoc NETworks (MANETs)."
>> 
>> 
>> The draft started out from where the deployments exist, which some call LLNs. However, as a basic reactive protocol, LOADng also covers the more general MANET case that includes a wider ranger of resources (from extremely constrained to not-so-constrained) and mobility. In particular, by supporting RFC5444 it fits well in the MANET architecture and the surrounding security extensions, flooding optimizations and TLVs etc. for RFC5444.
> 
> When you say, "draft started out from where the deployments exist",
> where these implementations DYMO, which draft?

Sorry that I was unclear, I meant LOADng.



> 
> Since 5444 was just added to the Loadng draft, is there an implementation using 5444?

Other authors may be more knowledgeabe to reply to this. Note that RFC5444 is decoupled from the core protocol mechanism.


> 
> 
>> I hope I could shed some light on that question. I invite you to read both drafts, there is probably more to say here.
>> 
>> I won't go into details here, but most of the discussions we had were not so much about technical issues, but about procedural. LOADng has started when DYMO was stalled for more than 2 years. I think we have a well mature document, supported by strong industry backing and running code. The latter is crucial in the IETF.
> 
> I'm curious why the Loadng effort did not/could not work through the WG to re-invigorate the DYMO discussions. 
> 
> 
> January 2005 - draft-ietf-manet-dymo-00
>    - Mobile Ad hoc Networks Working Group
>    - Expires: July 5, 2005
> 
> ... several draft updates ...
> 
> December 5, 2008 - draft-ietf-manet-dymo-16
> 
> March 8, 2009 - draft-ietf-manet-dymo-17
>    - Expires: September 9, 2009
> 
> February 23, 2010 - draft-ietf-manet-dymo-18
>    - Expires: August 27, 2010
>    - This draft included RFC5444 formatting
> 
> March 22, 2010 - draft-ietf-manet-dymo-19
>    - Expires: September 23, 2010
> 
> July 10, 2010 - draft-ietf-manet-dymo-20
> 
> July 26, 2010 - draft-ietf-manet-dymo-21
>    - Expires: January 27, 2011
> 
> *October 24, 2011 - draft-clausen-lln-loadng-00
>    - Title: The LLN On-demand Ad hoc Distance-vector
>      Routing Protocol - Next Generation (LOADng)
>    - Abstract: This document describes the LLN Ad hoc On-Demand (LOAD) distance
>      vector routing protocol, a reactive routing protocol intended for use
>      in Low power Lossy Networks (LLN).  The protocol is derived from AODV
>      and extended for use in LLNs.
> 
> *October 31, 2011 - draft-clausen-lln-loadng-01
> 
> March 12, 2012 - draft-ietf-manet-dymo-22
>    - Expires: September 13, 2012
>    - Rebranding the protocol was included:
>      Dynamic MANET On-demand (AODVv2) Routing
> 
> *March 12, 2012 - draft-clausen-lln-loadng-02
> 
> *March 29, 2012 - draft-clausen-lln-loadng-03
> 
> *April 22, 2012 - draft-clausen-lln-loadng-04
> 
> *July 14, 2012 - draft-clausen-lln-loadng-05
>    - C. Perkins, Futurewei Inc. was added as a co-author
>    - This line was removed from the Abstract: "The protocol
>      is derived from AODV (RFC3561) and extended for use in LLNs."
>    - This draft included RFC5444 formatting
> 
> October 23, 2012 - draft-ietf-manet-dymo-23 
> 
> *October 22, 2012 -  draft-clausen-lln-loadng-06
>   - Added J. Dean from Naval Research Laboratory


I was replying to your technical questions, but prefer not to go into history until the chairs reply.


Best regards
Ulrich


> 
> 
> 
>> 
>> Best regards
>> Ulrich
>> 
>> 
>> 
>> 
>> Thanks
>> -Bo
>> 
>> 
>> 
>> On Oct 22, 2012, at 8:03 PM, Axel Colin de Verdière wrote:
>> 
>>> Dear all,
>>> 
>>> we have updated LOADng, to make it clear that it is in scope and charter for MANET. Unfortunately, it is only a minor revision of the technical content, since we have been in discussions with the DYMO authors and the WG leadership for several months on how to proceed with the reactive protocol in MANET. The chairs will likely reply very soon to the list with an outcome of the discussion.
>>> 
>>> Best regards,
>>> 
>>> Axel Colin de Verdiere
>>> 
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