[Ns-developers] [ns] big delay by MAC-802_11 bug

[anas]

dear David,

I have done what you have said, but I figured out that there is no packets 
in the queue
may be there is another reason
as you will see in the trace file of node 25, it works regularly and it 
received many data and control packets and forward it normally within the 
period which packet 585 is still waiting ( 202-358) I send you the trace 
file of 585 packet .

Regards

--------------------------------------------------
From: "David Ross" <David.Ross at isrc.qut.edu.au>
Sent: Thursday, April 09, 2009 2:04 AM
To: "anas" <saba717671 at hotmail.com>
Subject: Re: [ns] big delay by MAC-802_11 bug

> Anas, if you grep out all the "_25_" entries, you should be able to work 
> out how many packets it has queued at 202 seconds (all the ones the RTR 
> has sent less the ones the MAC has sent on) to see if this really is the 
> problem.
>
> Like if the MAC just sent packet 100, but the RTR just queued 585, look 
> back to see what other packet IDs are in this node and count them until 
> you get to the one the MAC just sent at 202 seconds.
>
> Hope that helps - David Ross.
>
> anas wrote:
>> thank you sooooo much David
>> so what I will try to minimize the queue length  to improve my end to end 
>> delay
>> is it right
>>
>>
>> --------------------------------------------------
>> From: "David Ross" <David.Ross at isrc.qut.edu.au>
>> Sent: Thursday, April 09, 2009 1:35 AM
>> To: "anas" <saba717671 at hotmail.com>
>> Cc: "ns" <ns-users at ISI.EDU>
>> Subject: Re: [ns] big delay by MAC-802_11 bug
>>
>>> Anas, the delay is not the MAC, it is the RTR to the MAC, which is the 
>>> IFQ.  The only time I see these delays is with lots of nodes and lots of 
>>> queued packets, say 50 queued and each takes 3 seconds to win contention 
>>> = 150 seconds for the packet to get out.
>>>
>>> - David Ross
>>> QUT, Australia. (UTC+10hours)
>>>
>>> anas wrote:
>>>> Dear all,
>>>>
>>>> I have encountered a large delay end to end delay
>>>> and when I checked the out put file I see some of the packets have a 
>>>> very large delay at MAC layer as shown below:
>>>>
>>>> f 202.663960039 _25_ RTR  --- 585 cbr 576 [13a 2b 19 800] ------- 
>>>> [9:1 10:1 25 30] [17] 7 2
>>>> s 358.840523771 _25_ MAC  --- 585 cbr 634 [13a 1e 19 800] ------- 
>>>> [9:1 10:1 25 30] [17] 7 2
>>>> as it appears there is about 150 second at MAC layer
>>>>
>>>> what is the bug here
>>>> I used NS2.33 under both Linux and sygwin all of them have the same bug
>>>>
>>>> please help me
>>>> best regards
>>>> Anas
>>>
>>>
>
> 
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