How TCP Works - Window Scaling Graph

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How TCP Works - Window Scaling Graph

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4 жыл бұрын

Let's dig into the Window Scaling Graph and learn how to use it to measure the receive window on a target device, along with bytes out from a sending device. Sample trace file:
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Пікірлер: 51

@pedrojaviermunozgarcia3721 4 ай бұрын

Chris, I have gone through all your videos and I have nothing more to do than thank you. Great job, spotless and clear. You saved me a lot of time study time!!!

@AcTheMace 2 жыл бұрын

Thanks!! Saved my grade for this homework.

@netskills 3 жыл бұрын

That's awesome that you share the trace file! Keep it up!

@ChrisGreer 3 жыл бұрын

Thanks, will do! Stay tuned....

@mohitkhanna83 2 жыл бұрын

Very useful my friend. Simple. To the point. Informative. Crisp! Thanks for covering only a small module.

@miguelzambrano2389 3 жыл бұрын

Many thanks for these video Chris they are amazing!! I usually learn way better with videos than reading books many thanks for this content!

@ChrisGreer 3 жыл бұрын

You are welcome. Thanks for the comment!

@spencerwilson-softwaredeve6384 2 жыл бұрын

Awesome video, my instructor wants to make network security as confusing as possible it seems, you make it sound simple and now I understand what's going on. Thanks.

@ChrisGreer 2 жыл бұрын

Glad it helped you Spencer. Hey - check out my new course around cybersecurity with wireshark too! bit.ly/wiresharkhunt

@brahmadude8955 4 жыл бұрын

My TCP Guru

@ChrisGreer 4 жыл бұрын

Thanks sir! Glad you liked it. I'll keep them coming!

@unknownnespile9118 4 жыл бұрын

It's good to see you back.

@ChrisGreer 4 жыл бұрын

Thanks!

@cabsandy 4 жыл бұрын

Cracking short video Chris-and liking the new background and mic set-up. Looks like a nice desk as well! :-)

@ChrisGreer 4 жыл бұрын

Thanks for the comment! Just set up the new studio and getting ready for much more content. Stay tuned.

@nerfherder2915 4 жыл бұрын

great vid! keep pounding us with tcp/ networking info.. it will stick, eventually!.. solid Volcom shirt too!

@ChrisGreer 4 жыл бұрын

:-) Thanks nerf! I will keep it up

@remoscott1 4 жыл бұрын

Thank you again, Chris! Keep up the great work.

@ChrisGreer 4 жыл бұрын

Thanks, will do!

@lingfish1 2 жыл бұрын

Awesome stuff mate. Discovered you today; amongst all the noise and crap out there, you explain things well, even for this seasoned network guy ;)

@ChrisGreer 2 жыл бұрын

Thanks and welcome!

@smilefaxxe2557 10 ай бұрын

Thank you so much!!! This helped me a lot! ❤

@mattchiles771 3 жыл бұрын

Great set of vids and very usefull.

@ChrisGreer 3 жыл бұрын

Thanks for the comment Matt. Keep on capturing!

@juanparra386 3 жыл бұрын

Excelent video Chris. Thank you for your great explanation.

@ChrisGreer 3 жыл бұрын

My pleasure! Happy to help Juan

@shijianmin6159 4 жыл бұрын

Very helpful, thanks!

@ChrisGreer 4 жыл бұрын

Glad it was helpful!

@vikrantd9675 3 жыл бұрын

Many thanks for ur video.. really amazing..is there any video to troubleshoot intermediate application issue in wireshark....

@gregnstuff1118 4 жыл бұрын

Nice, can't wait to get a top zero window customer just to look at it in the 📊

@DeepakKumar-io1bu 3 жыл бұрын

Great explanation

@ChrisGreer 3 жыл бұрын

Thanks Deepak!

@zelllers 4 жыл бұрын

riverbed should just hire you honestly

@shirtguy9322 4 жыл бұрын

Bro these vids are great 😍👌

@ChrisGreer 4 жыл бұрын

Glad you like them!

@shirtguy9322 4 жыл бұрын

@@ChrisGreer holy fuck Chris Greer replied to my comment

@mattchiles771 3 жыл бұрын

Looking forward on a series on WiFi maybe?

@ManideepLadi Жыл бұрын

Thank you for this information. I have one question will be able to get Number of RTTs from Wireshark?

@ChrisGreer Жыл бұрын

We can measure the RTTs and plot them on the Round Trip Graph but I don't see a specific number of plot points. Have to keep tinkering...

@ManideepLadi Жыл бұрын

@@ChrisGreer Thank you for your response. I think you should make a video on how different congestion control provider works like Cubic.

@ManideepLadi Жыл бұрын

One more question @Chris Greer. Can we approximate total time for request as multiplication of round trip time and number of rtts?

@jarbystark Жыл бұрын

And what means if bytes cross the green line ? i saw it a couple of times in my caps, could it happen if windows size cant be calculated precisely because there is no syn-synack-ack in capture?

@VultUxTube 4 жыл бұрын

Thank you for the videos! I try to follow what you explain, but the problem is what to do next? For example, a problem with retransmissions has been identified because the window size is small, how to fix it?

@ChrisGreer 4 жыл бұрын

Sure, glad you are enjoying them. You asked a very good question. What do we do with a low-window issue? Or retransmissions? Well, in the case of retransmissions, we need to track down where on the network we are seeing packet loss. This usually requires some more tools - like iPerf for example for measuring throughput. If we have a low window problem, then we can do some research into that exact issue - searching for the application in use and the device type. Usually we can come across recommendations from the developer or others who have tuned that system in a similar way. So it really just depends on what we find, but at least the packets helped us be confident about what to focus our troubleshooting on.

@yohanmeier6061 3 жыл бұрын

hi chris, the green line which represents the tcp window is that of host which receives the data? for example one displays the graph in the direction PC1 towards PC2, the data in flight are those of the PC1 and the window of reception of the pc2?

@ChrisGreer 3 жыл бұрын

You got it - the green line shows the receiver, the dark blue is the sender.

@yohanmeier6061 3 жыл бұрын

@@ChrisGreer thank you

@PacketBomb 4 жыл бұрын

Have I just ignored Bytes Out or is it relatively new? Very cool

@ChrisGreer 4 жыл бұрын

It's been there for a bit - I don't know exactly when it was added but I have noticed it for some time. It's awesome for getting an idea on the congestion window.

@gauravpatel8810 4 жыл бұрын

Hi Chris, I have one question regarding tcp window. I have trace file in which sender and receiver not set window scale option in 3 way hand shake but eventually windows size increased in subsequent packets more then they set in first 3 packet. Can you please let me know what could be the reason.

@ChrisGreer 4 жыл бұрын

Hello Guarav, this is very common. Systems don't want to devote more resource to a connection unless they have to. So it is common to see them start out with a low window and then gradually increase it. It depends on the application and OS, but this behavior is very common to see.