Re: [ns] queueing mechanism in ns

[Punyaslok Purkayastha <punya@pal.ece.iisc.ernet.in>]

hi,

immense thanks for the answer. 

Punyaslok.

On Fri, 28 Jul 2000, Tarik Alj wrote:

> 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 <punya@pal.ece.iisc.ernet.in>
> >To: l.wood@eim.surrey.ac.uk
> >cc: ns-users@isi.edu
> >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 
> 
>