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Re: [ns] queueing mechanism in ns
transmission delay is independent of the queueing here. In the trace you show
the packet arrives at an empty queue, it is immediately served. The transmission
delay is added after the dequeueing event (between - and r). Please read chapter
6 and 8 of the manual.
>Date: Fri, 28 Jul 2000 12:17:09 +0530 (IST)
>From: Punyaslok Purkayastha <[email protected]>
>To: [email protected]
>cc: [email protected]
>Subject: [ns] queueing mechanism in ns
>MIME-Version: 1.0
>
>
>hi,
>
>i am not quite sure i understand the exact queueing and delay mechanisms
>of ns. i am employing a tcp source going through a
>single link. the first two lines of output in my trace file are
>
>+ 0 0 1 tcp 750 ------- 1 0.0 1.0 0 0
>- 0 0 1 tcp 750 ------- 1 0.0 1.0 0 0
>
>now my tcp packets should suffer a transmission delay of .6 ms. however
>the output shows that the packet suffers no delay at all ( it gets
>enqueued and dequeued at the same time).
>
>however note (at a later portion of the trace file)
>
>r 0.0206 0 1 tcp 750 ------- 1 0.0 1.0 0 0
>
>the propagation delay of my forward direction link is 20ms; so that i do
>get that the said tcp packet arrives at the receiving end 20ms+.6ms later.
>
>i am perplexed by what is going on.
>
>Punyaslok.
Tarik