Subject: [manet] Re: OPNET 802.11 model ?

From: Mihail L Sichitiu <[email-masked]>
Date: Thu, 5 Jun 2003 13:05:51 -0400 (EDT)

Sunil,

I have very bad experience with the 802.11 model in Opnet. It seems to
work reasonably well in managed mode (i.e. with access points), but it
breaks badly in ad-hoc mode (which I assume you'd like to use, given the
list orientation).

The 802.11 model keeps changing with every version (every 3-6 months), so
if you fix some of the bugs, you'll have to fix the *same* bug over and
over again in the subsequent versions, on top of finding the new bugs.

Moreover, despite the commercial nature of the product, the support is
very poor: every time you call or email them you talk with a different
person, that understands more or less a part of your problem (from
scratch). The support persons are not the same as the programmers, so they
have no idea how a specific feature is implemented, or whether is
implemented at all.

I am planning to switch to ns-2 this summer, and I suggest you do the
same, and skip the pain we've been going through the last two years. I
also found a small bug in the ns-2 code 1 year ago, I'm not sure if it's
still there.

I didn't see any Opnet 802.11e models, and I expect that it will be a
while until they'll show up.

Best regards,
Mihail Sichitiu

_______________________________________________________
Mihail L. Sichitiu
Assistant Professor,              Phone: (919) 515 7348
Dept. of ECE, Campus Box 7911     Fax:   (919) 515 5523
NC State University
Raleigh, NC 27695-7911   http://www4.ncsu.edu/~mlsichit
_______________________________________________________

> Date: Wed, 4 Jun 2003 18:45:12 -0700 (PDT)
> From: Sunil Sharma <[email-masked]>
> To: [email-masked]
> Subject: [manet] OPNET 802.11 model ?
>
> --0-365983582-1054777512=:67739
> Content-Type: text/plain; charset=us-ascii
>
> Hi,
>
> I am new in modeling. Does anyone know if OPNET has correctly working 802.11 model ? Does anyone even know of 802.11e or 802.16 model in OPNET ?
>
> I am starting with my M.S thesis and I need to decide if I can use OPNET 802.11 model (of which I have already had lot of negative feedback from couple of users). So any feedback and work around would be very useful.
>
> Thanks
>
> Sunil
_______________________________________________
manet mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/manet

---

From: Vikram Dham <[email-masked]>
Date: Fri, 6 Jun 2003 11:42:36 -0400

I worked with vintage OPNET 8.0 when I was using 802.11 model and I had to 
make changes in physical layer to obtain even basic results. I am not sure how 
well it implements the features of Access Point or if it implements all the 
control mechanisms of 802.11.

Thanks

Vikram

>===== Original Message From John Stine <[email-masked]> =====
>Lily,
>
>    I did some modeling with the OPNET's 802.11 model in an older version and 
found that it did not serve my needs so I revised it.  Later I sent my 
revisions to OPNET and they then added the features I  wanted in the next 
upgrade.  I believe if you find a deficiency in one of their models they are 
more than will to correct it.  The key is documenting your changes well and 
explaining why you are making them.  I used a search string to help the OPNET 
engineers find my changes.  They want their models to be the best they can be.
>
>    The physical model in opnet is implemented in stages.  You have full 
control of each stage and can add a number of features unique to your 
research, for example, a completely different modulation scheme or unique 
propagation model.  Also, you probably can find some additional models, if not 
now, later, that users have developed to enhance the physical layer models.  I 
have not worked with their 802.11 model for a while now but when I last used 
it, one feature I wished was modeled was the process of selecting the data 
rate and then the modeling
>of interference amongst radios using different data rates.  The model I am 
familiar with, ( version 7), did not show this interference.
>
>John
>
>"Yang, Lily L" wrote:
>
>> Hi, Mihail --
>>
>> I just started using OpNet for our multi-hop ad hoc network simulation and 
already had issues with it. For example, static routing doesn't work at all 
and so it is hard to simulate multi-hop static routes unless using some 
cumbersome workaround. Since you've had some experience already and would you 
care to elaborate some of the trouble you've encountered? That might help me 
make up my mind in picking the right simulation tool. What I heard so far is 
that the PHY model in OpNet is much better than ns-2 and others. what is your 
opinion on that?
>>
>> Thanks,
>> Lily
>>
>> -----Original Message-----
>> From: Mihail L Sichitiu [mailto:[email-masked]]
>> Sent: Thursday, June 05, 2003 10:06 AM
>> To: [email-masked]
>> Subject: [manet] Re: OPNET 802.11 model ?
>>
>> Sunil,
>>
>> > I am new in modeling. Does anyone know if OPNET has correctly working 
802.11 model ? Does anyone even know of 802.11e or 802.16 model in OPNET ?
>> >
>> > I am starting with my M.S thesis and I need to decide if I can use OPNET 
802.11 model (of which I have already had lot of negative feedback from couple 
of users). So any feedback and work around would be very useful.

---

From: Sarah Cartwright <[email-masked]>
Date: Fri, 06 Jun 2003 12:02:39 -0400

Hi everyone:

I just wanted to share a few quick comments about OPNET's 802.11 model and 
support--

The current release of OPNET products is version 9.1.  If you haven't seen 
us recently, it may well be worth your while, as it contain many 
enhancements, including:
- reception power threshold (for more accurate modeling of receiver 
sensitivity and spatial reuse)
- PLCP header and preamble overhead effects
- significant performance enhancements during simulation
- numerous fixes to previously reported software problems

Future OPNET 802.11 model releases are expected to have further physical 
layer enhancements and roaming capabilities.

We are dedicated to quality and accuracy in results, and we do our very 
best to provide a fix or workaround for any reported problem that affects 
customer studies.  The developers who create our software are also the 
engineers who directly provide support, so you can count on OPNET support 
staff to be technical and familiar with the software, to quickly find the 
answers you're looking for.  Support procedures have recently changed for 
universities as well, in response to your many requests.  For instance, 
student access to online resources has been expanded.

Thanks for your time---if you have questions or concerns about OPNET 
products or services, please don't hesitate to contact us at [email-masked].

---------------------------------
Ms. Sarah CARTWRIGHT ([email-masked])
Director, Technical Support
OPNET Technologies, Inc.  (http://www.opnet.com/)
phone 240.497.3000
---------------------------------
Register for OPNET's Online Technology Workshops
(http://www.opnet.com/TechWorkshops/)
---------------------------------
Register for OPNETWORK 2003 (August 25-29, in Washington DC)
(http://www.opnet.com/opnetwork2003/)
---------------------------------