Subject: [manet] Oct 2012 IEEE Communications Magazine article discussing DLEP

From: [email-masked]
Date: Thu, 25 Oct 2012 14:32:58 -0500

I finally finished catching up on over a month of manet emails and don't 
remember seeing any mention of the Oct 2012 IEEE Communications Magazine 
article on "Radio-to-router interface technology and its applicability on 
the tactical edge" by Bow-Nan Cheng, James Wheeler, and Leonid Veytser of 
MIT Lincoln Laboratory.

The article discusses the need for radio to router interface (R2RI) 
protocols for smart cross-layer multihop routing.  The article examines 
and compares 
- RFC 5578 [PPP over Ethernet (PPPoE) Extensions for Credit Flow and Link 
Metrics], 
- R2CP (Radio-to-Router Protocol), and 
- DLEP.

The article can be found at 
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6316778

I thought the article did a good job of discussing the issues of 
developing such R2RI protocols and the advantages and disadvantages of RFC 
5578, R3CP, and DLEP. 

Some of the R2RI issues I thought particularly applicable to the manet 
area I work in are paragraphs entitled "Flow Control", "Variable Rate and 
Power Radio Systems", "R2RI Handling of Multicast Flows", "Link Metric 
Dampening and Hysteresis", and "Link Load Affect on Link Metrics".  I also 
agreed with the statement that I think is general (although only stated in 
the paragraph on RFC 5578 disadvantages) that "Lack of a proper 
feed-forward mechanism [e.g., router-to-radio requests]: Military radio 
systems often need some information about incoming traffic to allocate 
time slots and perform resource management."

The article discusses in the paragraph entitled "Radios' Bridge-Mode 
Capability" that "a basic assumption of R2RI is that future systems will 
allow bypassing of built-in multihop routing techniques, allowing the 
radio to merely act as a layer 2 RF link."  I agree that this makes sense 
for many (most?) cases, and in particular high-speed directional backbone 
radios.  However, I think that R2RI protocols should also support radios 
to perform built-in multihop routing where it makes sense, such as low 
capacity, edge, manets networks where the nodes often only have a single 
network interface (i.e., the manet radio network) and radio multihop 
routing optimizations can significantly improve performance. 

Jim Stevens

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From: Bo Berry <[email-masked]>
Date: Fri, 26 Oct 2012 06:33:19 -0400

Jim
Thanks for sharing this article.  The MIT Team did a lot of great work!

If you have specific requirements/suggestions for feed-forward needs, please let us know.

DLEP is also reserving a number of experimental TLVs.  If needed, these can be used to further develop various concepts.

Thanks
-Bo

On Oct 25, 2012, at 3:32 PM, <[email-masked]> wrote:

> 
> I finally finished catching up on over a month of manet emails and don't remember seeing any mention of the Oct 2012 IEEE Communications Magazine article on "Radio-to-router interface technology and its applicability on the tactical edge" by Bow-Nan Cheng, James Wheeler, and Leonid Veytser of MIT Lincoln Laboratory. 
> 
> The article discusses the need for radio to router interface (R2RI) protocols for smart cross-layer multihop routing.  The article examines and compares 
> - RFC 5578 [PPP over Ethernet (PPPoE) Extensions for Credit Flow and Link Metrics], 
> I thought the article did a good job of discussing the issues of developing such R2RI protocols and the advantages and disadvantages of RFC 5578, R3CP, and DLEP. 
> 
> Some of the R2RI issues I thought particularly applicable to the manet area I work in are paragraphs entitled "Flow Control", "Variable Rate and Power Radio Systems", "R2RI Handling of Multicast Flows", "Link Metric Dampening and Hysteresis", and "Link Load Affect on Link Metrics".  I also agreed with the statement that I think is general (although only stated in the paragraph on RFC 5578 disadvantages) that "Lack of a proper feed-forward mechanism [e.g., router-to-radio requests]: Military radio systems often need some information about incoming traffic to allocate time slots and perform resource management." 
> 
> The article discusses in the paragraph entitled "Radios' Bridge-Mode Capability" that "a basic assumption of R2RI is that future systems will allow bypassing of built-in multihop routing techniques, allowing the radio to merely act as a layer 2 RF link."  I agree that this makes sense for many (most?) cases, and in particular high-speed directional backbone radios.  However, I think that R2RI protocols should also support radios to perform built-in multihop routing where it makes sense, such as low capacity, edge, manets networks where the nodes often only have a single network interface (i.e., the manet radio network) and radio multihop routing optimizations can significantly improve performance.   
> 
> Jim Stevens 
> _______________________________________________
> manet mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/manet

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From: Abdussalam Baryun <[email-masked]>
Date: Mon, 29 Oct 2012 15:27:29 +0100

Hi

> the tactical edge" by Bow-Nan Cheng, James Wheeler, and Leonid Veytser of

It was not mentioned because it is new article, we are still in
october 2012. I don't see that the article authors discussed DLEP work
on the IETF MANET list.

> protocols for smart cross-layer multihop routing.

They argue issues but did not discuss with us. Could you explain what
is smart cross-layer routing? do we have this kind of routing in
MANET-IETF or is it out MANET-IETF?
However, I agree that we need more work for R2RI mechanisms as we do with DLEP.

>  The article examines

The article does not examine/tests the protocols, but compares
features without  performance including applicability issues.

> developing such R2RI protocols and the advantages and disadvantages of RFC

- You mean DLEP-02 not the final DLEP still discussions within MANET-WG
- I don't agree with article's Figure 1, of the three componenets, I
prefer the DLEP draft descriptions. However, Figure 4 is more clear.
However, I agree that the article provide good introduction, maybe
used as definition reference.

Finally, there is still work going within R2RI area, including DLEP,
but I think that DLEP seems special case of R2RI or maybe not a R2RI.

AB

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From: Joseph Macker <[email-masked]>
Date: Mon, 29 Oct 2012 10:35:49 -0400

> october 2012. I don't see that the article authors discussed DLEP work

FYI, the authors (Cheng) did provide an initial set of input to the manet
WG in the form of a briefing and a personal Internet draft. If you see past
minutes you will see a brief summary of what was discussed.