[ns] 802.11 Carrier sense

[Sorav Bansal]

The call to is_idle in the function check_pktRTS() is the call to is_idle
before an RTS is to be dispatched.

--sorav



                                                                                                
                    shshah@cairo.c                                                              
                    s.uiuc.edu           To:     Sorav Bansal/India/Contr/IBM@IBMIN             
                                         cc:     ns-users@ISI.EDU, <ns-users-admin@ISI.EDU>     
                    04/15/02 09:33       Subject:     Re: [ns] 802.11 Carrier sense             
                    PM                                                                          
                    Please respond                                                              
                    to shshah                                                                   
                                                                                                
                                                                                                



On Mon, 15 Apr 2002, Sorav Bansal wrote:

>
>
> Hi,
>     The function is_idle() in mac-802_11.cc checks if the medium is idle
or
> not (carrier sensing).

Yes, I am aware of this, but I would like to know which particular call to
is_idle() is the *first* carrier sense before the *first* RTS is sent.
is_idle() is checked multiple times in mac-802_11.cc, I am only interested
in the particular above case. Could you give me this info? Thanks in
advance.

Regards,
Samarth.

The medium is not idle if a packet is being
> received. And all packets with signal strength above the carrier sense
> threshold are received by the MAC layer (except that the error field is
set
> to 1 for packet below the receiving threshold). Hope that answers your
> query.
> --sorav
>
>
>
>

>                     shshah@cairo.c

>                     s.uiuc.edu           To:     ns-users@ISI.EDU

>                     Sent by:             cc:

>                     ns-users-admin       Subject:     [ns] 802.11 Carrier
sense
>                     @ISI.EDU

>

>

>                     04/15/02 01:12

>                     PM

>                     Please respond

>                     to shshah

>

>

>
>
>
>
> Hi,
>
> I'm unable to discern exactly when (i.e. where in the 802.11 code) the
> first carrier sense before the first RTS for a packet occurs. If the
> carrier is found busy at this carrier sense, I would like to be able to
> modify the backoff interval after the deferral that follows the busy
> carrier sense. Rather than have the station backoff cw_ slot times, I'd
> like to have it backoff some other number of slot times.
>
> I do not wish to modify the backoff procedure that is followed after a
> collision, however. I want the cw_ doubling, backoff = cw_ number of
> slots, etc. to remain as is, in the case of collision.
>
> Could anyone kindly provide me some guidance? Thanks in advance.
>
> Regards,
> Samarth.
>
>
>
>
>
>
>
>