periodic restart of bulk send application

[tushar mathur]

Hi,

Is there a way to periodically restart the bulk send application?  I want to use the application, such that, it can be rescheduled to send the MaxBytes every 2 seconds(and try to fill the bandwidth of the link) until simulation is stopped at simulation end time?

If not, are there any known techniques or examples that might help in creating such a scenario?

Any help is very much appreciated.  Thanks in advance for your time.

-Tushar

[Tommaso Pecorella]

Hi,

What about using the OnOffApplication ? It should do the trick

[tushar mathur]

Thanks for the answer Tommaso.

If I use OnOffApplication, do I need to input the data-rate compulsorily? or can I make it work similar to bulkSendApplication by just using MaxBytes, OnTime and OffTime attributes?

I tried the scenario, but it did not yield the same results as bulk send application... because it did not fill up the bandwidth and I wanted to measure the throughput on the link when bandwidth gets filled quickly.

I hope my understanding of application is in the right direction.  I have attached my scripts if they can help answering my question.

Thanks again, for your time and help!

-Tushar

[Konstantinos]

Hi Tushar,

By default the OnOffApplication data rate is 500kbps but I see that your p2p links are nearly 2Gbps. 

You can make the application rate much higher to fill up the buffer.

[tushar mathur]

Hi Konstantinos,

Thanks for answering so quick!

I agree that making the application rate higher would fill up the bandwidth, but that means I am defining a limit to the data-rate. While in bulksend application, I believe the application changes the data-rate dynamically to fill up the link buffer as quick as possible, right?

Is there a way to achieve this functionality in on off application?

Best,

-Tushar

[Konstantinos]

It is a bit misleading name, I agree, but there is a difference in 'application-datarate' and 'link-datarate'.

In principle, Bulk has an infinite application datarate, it pushes ALL data down to the TCP buffer instantly.

OnOffApplication datarate controls the rate of generated packets (at application rate), i.e. the rate at which packets reach the TCP buffer. So you can set that rate e.g. to 10Gbps and control the number of packets to match that of Bulk. Also proper care in the On/OffTime is needed. 

In both cases, TCP congestion control mechanism will control the data rate at the link level.

[tushar mathur]

Okay. I understand it now... Thanks very much! 

This explanation made it very helpful.

On a side note, I would like to add that this forum is very good because of the quick and helpful replies that I have received always.

Best,

-Tushar