[ns] Fwd: Problem with mhDefer_ timer in mac-802_11.cc

[Mayur]

varun at cs.iastate.edu wrote:
>
> ----- Forwarded message from varun at cs.iastate.edu -----
>     Date: Fri, 21 Nov 2008 13:54:37 -0600
>     From: varun at cs.iastate.edu
> Reply-To: varun at cs.iastate.edu
>  Subject: Problem with mhDefer_ timer in mac-802_11.cc
>       To: ns-users at isi.edu
>
> Hi all,
>
> I am trying to introduce a delay in sending packets from the sendCTS() and
> sendACK() functions by using the defer timer mhDefer_.
> However I see that the number of packets sent with and without the use of the
> mhDefer_ timer is the same. I am not seeing the desired effect. Anyone has a
> clue why?
>
> Also, is this the right approach to introduce a delay before sending a packet?
> If not could you please let me know what the right procedure is?
>
> Any input will be greatly appreciated.
>
> Thanks in advance,
> Varun
>
>
>
> ----- End forwarded message -----
>
>
>
>   
Yes, I think, this should be the right approach if you are interested in 
introducing Random delay based on the CW, (rather than fixed SIFS) in 
sending of CTS and ACK packets.

In your case, it may be affecting actually. Don't just count the number 
of packets, rather analyze the trace file and see the time taken between 
"receipt instant of an RTS (DATA) and sending instant of CTS (ACK)" at 
any node, and compare it with the simulation run without your 
modification. You must get the difference, thats all. This is because if 
the overall traffic is less, the number of packets may not reduce, for 
some given time duration, I suppose.

If it is giving same SIFS period (fixed) in both the cases, than there 
is some problem. Then, you may send the snippet of the mac-802_11.cc 
which you changed to effect this?

regards,
Mayur