[ns] IEEE 802.11 MAC implementation in NS2
maguolof at dei.unipd.it
Thu Jun 1 04:28:06 PDT 2006
> However, this bug fix does not aim to solve this PSEUDO BACKOFF
Your conclusion seem to be drawn from a not correct understanding of the
If you read carefully the bug description, you will understand that in
original module there are two backoff procedures: one correct and
non correct (which implement the PSEUDO BACKOFF). The aim of the fix is
to get rid of the PSEUDO BACKOFF.
On Thu, 2006-06-01 at 00:17, Bo Wang wrote:
> Hi, all,
> The following "Bug Fix"
> pointed out that
> " The *send* procedure begins with the 'send' method of the class
> 'Mac802_11' in 'mac-802_11.cc' file. First, *send* checks whether the medium
> is idle and no previous backoff procedure is pending. If the response is
> true, *send* calls the internal DeferTimer procedure, which should simulate
> the random backoff stage described by the IEEE 802.11 standard. Notice that,
> despite what dictated by the standard concerning the backoff stage the
> internal DeferTimer procedure DOES NOT freeze the timer contdown if the
> channel becomes busy, since the channel sensing procedure is not considered.
> For this reason, in the following we will refer to this backoff procedure as
> PSEUDO BACKOFF."
> However, this bug fix does not aim to solve this PSEUDO BACKOFF problem.
> My question is that if the backoff procedure does not freeze the timer
> countdown which is a big deviation from the standard, can we still use NS2
> do wireless simulation? It seems that a lot of research papers use NS2.
> Is the timer countdown freezing properly implemented in real wireless
> I would like to hear your opinion on this issue.
> Thank you very much!
> Bo Wang
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