Re: [ns] Problem about the implemention of mac802_11

[Joe Macker <macker@itd.nrl.navy.mil>]

At 11:46 PM 8/27/2001 -0700, Yun Li wrote:
>A simple example is the "void send(Packet * p, Handler
> *h)" function in Mac-802_11.cc. In this
>function,there 
>are some statements like:
>"
>if(mhBackoff_.busy()==0) {
>    if(is_idle()) {
>       if(mhDefer_.busy()==0)
>                mhDefer_.start(difs_);
>     }
>else {
>     mhBackoff_.start(cw_.is_idle());
>     }
>}
>"
>    From these statements,we can conclude that when 
>the media is busy, backoff a random time;else, defer
> difs_ time and send the packet. But the Mac802.11
> standard requires that even if the media is idle,the
> mac sender must backoff a random time. THIS IS THE
> FIRST CONFLICT that i can see.

There should be a random backoff contention process after a "difs_idle" transmission deferral window. Could someone look into this and verify its not working right?

-Joe