Subject: opnet models?

From: Ken Peirce <[email-masked]>
Date: Thu, 13 Dec 2001 10:24:07 -0800

Are there Opnet models for any of the MANET protocols?
Thanks,
Ken

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From: Yih-Chun Hu <[email-masked]>
Date: Thu, 13 Dec 2001 15:21:26 -0500 (EST)

Ken,

NIST has models for DSR and AODV:
DSR	http://w3.antd.nist.gov/wctg/prd_dsrfiles.html
AODV	http://w3.antd.nist.gov/wctg/manet/prd_aodvfiles.html

Unfortunately, their model for DSR is somewhat problematic, for at least
the following reasons, all taken from their README file: 

	- Piggybacked Errors are not implemented (p6)

	- Promiscuous mode is unimplemented (p7), though it provides
	  roughly a 3-to-5-fold improvement in our ns models.

	- Send Buffer timeout is unimplemented (p8), though it provides a
	  _reasonable_ PDR/Latency/Overhead tradeoff (AODV also has a
	  request limit, and it's a good thing to do).

	- Doesn't check send buffer for each insertion into Route Cache
	  (p8), which they believe (without experimentation) is
	  unnecessary since they don't implement promiscuous mode

	- Their route cache is severely broken (p9). In accordance with
	  the draft, a route cache SHOULD have the ability to store
	  multiple routes to a destination. Work has been done on caching,
	  and we know that a broken cache can severly hamper the
	  effectiveness of DSR.
		http://citeseer.nj.nec.com/hu00-caching.html

	- No salvaging (p11). In our experiments, salvaging with a 
	  reasonable cache provides a significant boost to PDR, with
	  minimal overhead cost. Salvaging has been a part of DSR prior to
	  dsr-02.

I don't represent the above to be a complete list of issues, as I haven't
read their code; however, with just these issues, I'm inclined to believe
that drawing any conclusions from simulations performed with the DSR model
as-is would be substantially inaccurate. 

The NIST AODV project is listed as work in progress. They don't appear to
have implemented blacklists (though they may not be necessary if the
simulator doesn't create unidirectional links). It's difficult to tell
from the release notes whether or not they left out any other features of
AODV.

Hope this helps,
Yih-Chun

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From: Jason Ballah <[email-masked]>
Date: Thu, 13 Dec 2001 15:22:15 -0500

Ken,

The National Institute of Standards and Technology has designed and 
contributed OPNET models of the DSR and AODV MANET protocols.  The AODV 
model was designed to the draft-ietf-manet-aodv-08 and it looks pretty 
accurate from what I have seen of the documentation.  The DSR model was 
designed to draft-ietf-manet-dsr-03 but it left out a large number of 
critical (this is in my opinion) options that greatly (adversely) affect 
its performance compared to the performance data that has been published 
for DSR.  I am currently in the process of upgrading this model to the 
latest DSR specification, so if you would like more information on the 
DSR model let me know.

Both of these models can be found under the contributed models webpage 
of www.opnet.com or you can go to the NIST website at 
http://w3.antd.nist.gov/wctg/manet/index.html and download them there.

Jason Ballah

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From: Nishant Gupta <[email-masked]>
Date: Thu, 13 Dec 2001 16:01:53 -0500 (EST)

Dear Ken
There are DSR models as contributed models from OPNET. You can get it
from
http://www.opnet.com/support/cont_models.html

Nishant Gupta
http://www.ececs.uc.edu/~guptanis
Email: [email-masked]

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