Tcp: Window scaling option

[Manpreet Singh]

Hi all,

I am new user of ns3.19 and I'm interested in working on window scaling option of tcp. I've found this link which tells about implementation of window scaling option https://codereview.appspot.com/24900043/. But I don't know how to merge these patches into ns3.19 or is it possible to merge them into ns3.19? If it is possible, how it can be done?

And if this option cannot be implemented in ns3.19, will it be merged into ns3.20?

Regards,
Manpreet Singh

[Tommaso Pecorella]

Hi,

no, Window Scale option will not make it for 3.20. It is currently being worked on by Natale Patriciello in this repo: http://code.nsnam.org/nat/ns-3-dev-socis2014/

Mind that the repo does contain also other stuff and may change in any moment.

T.

[Manpreet Singh]

Thanks for your help sir. Could you please tell me what is actually discussed in the link i've posted?
Is it related to future feature that will be implemented in ns3 or
can it be implemented somehow on current ns3.19 version?

Manpreet Singh

[Tommaso Pecorella]

The link I posted contains the window scale option upgraded for ns-3-dev, which is almost 3.20.

T,.

[Nat P]

Actually in the repo that Tommaso mentioned there is an alpha-alpha version of the Tcp Window Scaling option. If you want to do some test, you are free to do them, but please report any results you got (both failure or success), thank you!

[alex19...@gmail.com]

Hi,

     Currently I am working on high bandwidth network analysis. I want to use TCP Window Scaling Option, which is included in NS-3.21. But I don't know how to use this option in ns3 script. Can someone suggest any script example for this issue, OR what changes should be done in script examples in ns3/..../examples/tutorial.

Regards,

Alex

[Nat P]

Il giorno sabato 8 novembre 2014 07:51:40 UTC+1, alex19...@gmail.com ha scritto:

Hi,

     Currently I am working on high bandwidth network analysis. I want to use TCP Window Scaling Option, which is included in NS-3.21. But I don't know how to use this option in ns3 script. Can someone suggest any script example for this issue, OR what changes should be done in script examples in ns3/..../examples/tutorial.

Hi,

from the user (your) point of view, Window Scaling option has nothing to touch; it works automatically based on the tcp rx buffer size.

In other words, you can tune the rx buffer size, and the window scale will react accordingly (if enabled).

Have a nice day

[alex19...@gmail.com]

Hi,

I have considered both cases of window scaling enabled and disabled,  for ns-3.21/examples/tcp/tcp-large-transfer.cc. But I am getting the same throughput from both cases. For both cases, the p-cap file generating the same IO graph. But it should be different. Can you suggest any soluton for this?

I have attached tcp-large-transfer.cc file.

Regards,

Alex

[Nat P]

Il giorno martedì 11 novembre 2014 11:29:09 UTC+1, alex19...@gmail.com ha scritto:

Hi,

I have considered both cases of window scaling enabled and disabled,  for ns-3.21/examples/tcp/tcp-large-transfer.cc. But I am getting the same throughput from both cases. For both cases, the p-cap file generating the same IO graph. But it should be different. Can you suggest any soluton for this?

Why do you think that it should be different? In my opinion it SHOULD be the same.

In your topology, I expect an RTT of ~40 ms. So, with a cwnd of 65535 (the maximum allowed without window scaling) you have a throughput of:

th = cwnd / rtt = 65353 byte / 0.040 s = 1638375 Byte/s = 13107000 bit/s = 13.10700 Mbit/s

which exceed the 10 Mbit/s rate you have on your link.

Try to increase the datarate or the delay, and then enable/disable the window scaling... (high bandwidth network with 10 Mbit/s? Are we in 1975? :-D :-D)

Have a nice day :P

[alex19...@gmail.com]

Okay, my bad. I considered your suggestion, got the expected output by increasing the datarate and delay.

Thanks for help

Alex