Re: [ns] delay command in NS

[Vincent Loo <vincent@perthmail.com>]

hello Enrique, Huan and all,

i saw this on the ns-list and i was wondering how to use this "done" script, as i want to do the same delaying effect.

and can i ask how to do the RNG in ns? cos i don't follow the RNG example.

thanks



--- Huan Pham <huan@cs.jcu.edu.au>
> wrote:
>Hi Enrique and NS users,
>
>Thank you very much for your help, But I think your code asks TCP to schedule
>the next transmission based on the Current "Sending" time, not based on the
>time when TCP finishes sucessfully its transmission with ACKs confirmation.
>
>For example, according to your current solution, if you start sending first
>chunk of packets at 1.0 second, your next schedule time will be 31.0, 61.0,
>.... no matter how much it takes to transmit 20000 bytes!
>
>What I want to simulate is the "user behaviour". To do that I have to take
>the Thinking time (random time) and transmission time & ACK feedback time
>into acount. Then, if it takes 2 seconds to get the ACK feedbacks, the next
>tranmission time will be 33.0, 65.0 , ...  The expected outcome will be some
>thing like this: " if transmission time (application delay) is big, users
>themself will ease their traffic generation". And we may experience less
>traffic load.
>
>Are there any available traffic model that have done this?
>
>Thanks again very much for your help. I would appreciate very much your
>alternative solution to my problem.
>
>Huan Pham
>
>
>Enrique Campos-Nanez wrote:
>
>> You can use the "done" call back for the TCP agent,
>> and schedule a future event at that time. For example:
>>
>> Agent/TCP instproc done {} {
>>         set ns [Simulator instance]
>>         $ns at [expr [$ns now]+30.0] "$self send 20000"
>> }
>>
>> By the way, the FTP session is not necessary if you are only sending
>> information
>> in this fashion.
>>
>> Enrique Campos-Nanez
>>
>> On Thursday, May 17, 2001, at 07:45 PM, Huan Pham wrote:
>>
>> >
>> > What I want to simulate now is to have a FTP  traffic source. It
>> > generate 20 packets, each of 1000 bytes. It waits until transmission
>> > finished.  Then it delays an random time (let's say 30 seconds in
>> > average, stands for user reading time) before keep produce another more
>> > 20 packets.
>> >
>> > Can anyone tell me, if NS know when FTP finishes transmission , and
>> > what is the command  to do "Delay 30 second "  in  NS.
>> >
>> > Thanks
>
>--
>
>Huan Pham - PhD Student
>School of Information Technology
>James Cook University, QLD4811, Australia
>Phone: 61-7-4781 6909    Mobile: 61-418-875084
>Fax: 61-7-4781 4029
>Homepage: http://www.cs.jcu.edu.au/~huan

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