TCP - 12 simple ideas to explain the Transmission Control Protocol

[@PracticalNetworking]

📺🧩 TCP Masterclass: kzbin.info/aero/PLIFyRwBY_4bS-PQZoF0UySdG0sH9VA0bn 🚨📢 Announcement: *I'm creating a full Networking course!* Details --> pracnet.net/networking 📺🕸 Module 1 of the course is *free* : kzbin.info/aero/PLIFyRwBY_4bRLmKfP1KnZA6rZbRHtxmXi But what about the TCP Masterclass? I have about 10-12 lessons scoped out for a comprehensive TCP Masterclass, and I'd love to create it at some point. When I released the first three lessons, I offered a challenge: If any one video garnered 100k views in the first 6 months, I would create the full TCP Masterclass. Unfortunately, we didn't meet that goal, so I had to prioritize other projects. But I haven't given up hope! *If you are interested in seeing the full TCP Masterclass developed, then the best way to bring that to fruition is to spread the word about this content*. Doing so will help others fully understand TCP and UDP and bring me closer to committing to creating the full series... Plus, think of all the Internet Points you can get for sharing this series (likes, karma, follows, etc) 😉 If you share this series, please use this link: kzbin.info/aero/PLIFyRwBY_4bS-PQZoF0UySdG0sH9VA0bn Otherwise, I genuinely hope you got a lot out of the first three lessons. Thank you for all the encouraging words in the comments. =)

[@DeepakKumar-ov8ko]

Hi Ed, I am already a subscriber of tls/ssl course . Could you please tell me more about the newly launched networking course like you will OSPF,BGP in detail ? Just a small request on any update ipsec vpn as i am waiting for almost 5-6 years when i started following you😀 Any idea about length of course in hours ?

[@amitpatil1900]

Please share content of the course.

[@DeepakKumar-ov8ko]

Purchased this course.✌

[@nanosni]

Hi. When do you expect to release the completed course?

[@PracticalNetworking]

@@amitpatil1900 Details on the full course are in these two links: - classes.pracnet.net/courses/networking - www.practicalnetworking.net/index/networking-fundamentals-how-data-moves-through-the-internet/ More details will be added shortly

[@jamess1081]

Ed, I just wanted to take a moment to express my gratitude for the outstanding educational content that you provide on your KZbin channel. The educational network courses that you have created is one of the best on the platform, offering a wealth of information on a wide range of topics. Your courses are well-structured and easy to follow, making it accessible to learners of all levels. The level of detail and expertise you bring to each of your lessons is truly exceptional, and your passion for teaching shines through in every video.

[@PracticalNetworking]

[@Skiemlordd]

@@PracticalNetworking Absolute chad

[@gerard9203]

totally agree!

[@_Divine1]

@james1081 ditto. @practicalnetworking Thank you for the awesome content

[@Nayab-m8w]

The idea behind dividing the concepts into several ideas and explaining it one by one in detail it's just awesome.Loved the way you taught TCP.🙇‍♂️

[@khalidjibril9066]

I don't normally comment on KZbin videos but I just had to say that this is one of my favourite explanation videos ever. The video was super clear, easy to follow and the diagrams were icing on the cake. Thanks a lot mate!

[@dragonbg6105]

I would rate you top 1 teacher on youtube. Not only networking teacher, but like your networking teaching is the best teaching compared to teachers in any field.

[@PracticalNetworking]

[@arturpopielski7051]

100%

[@AL300bed]

The most comprehensive explanation of TCP I have ever watched. I am looking forwarding for the full TCP master class.

[@karthik2705]

This channel deserves better. Wonderful explanation. Learnt this clearly after 4 yrs in networking field

[@PracticalNetworking]

Glad this helped =). Most of my content is based around "How did I wish someone explained it to me when I was first learning"

[@AnantaAkash.Podder]

It is by far the BEST of BEST Tutorial for Explained TCP... Thanks a Lot Sir

[@sididoueida5705]

the most comprehensive explanation of TCP I've ever seen. Amazing ......

[@RohitVerma-wh1ki]

One of the best explanation of TCP i have ever seen. Thank you for making such informative and easy to understand vidoes for the complicated topics.

[@MrSENNAmagic]

My Dear Sir, You are an amazing teacher! I know there is more to learn about Network's g but you have planted the seed of curiosity in my mind!

[@shellohd8421]

I've never seen someone that is able to compress lectures long of material into 44 mins of video white taking the animations into consideration.. Keep up with the content !

[@PracticalNetworking]

Thank you for the kind words, and thank you for directly supporting the channel. Glad you enjoyed this video =)

[@fakeaccount3415]

Please continue the series . words cant explain how useful your content is .excellent animated content even normal people can understand the topic easily .

[@DreamsAPI]

WOW, the simplest and best video on tcp I have seen in all my life, thank you🎉🎉🎉🎉

[@PracticalNetworking]

You're very welcome! Thanks for the kind words =)

[@privacy312]

After watching every video on KZbin, I found this one, and it’s absolutely the best guide I’ve ever seen! I understood everything, and you always answer every question I’ve had in my head. You’re the best mentor ever for these topics. Thank you so much

[@dpi3]

one simply does not simply provide the best TCP video on the internet, but this man does. funnily, i was genuinely sad when BOB closed the connection on ALICE 😆

[@PracticalNetworking]

It's OK! They can initiate a new connection at any time ;p (jokes aside, thanks for the kind words, glad you enjoyed the video!)

[@ashutoshmahapatra537]

Just a word of appreciation I've networking exam today and your videos have gave a in-depth practical understanding that's very rarely found in others! :)

[@PracticalNetworking]

Fantastic, hope the exam went well!

[@leonardoffor6515]

Just finished this series and I must say I'm thoroughly impressed. You are God sent Ed. Thanks for making this free and accessible for all.

[@seradfb345]

I had gone through about 4 videos which left me a bit confused, but found your video had excellent clarity. Each point was explained without ambiguity and really helped me to get it. Thanks a lot!

[@TheDavood7]

I have never commented on KZbin videos throughout these years, but you made me do so with this video. This is the most comprehensive TCP video that I've ever seen. I watched your routing protocol videos, and those were awesome too. Please keep your videos "free" for those of us who live in countries where paying in dollars is so expensive that we can't afford it

[@СеваЦук]

I was looking for clear step by step explanation of how tcp works, glad that I found your channel :)

[@PracticalNetworking]

=)

[@mumtahinaparvin7668]

Before coming to this channel, i used to think i was the only one weak at networking and i had no possibility to learn it. But now i think it is possible to be boss at networking thanks to you.🥰

[@Xenji88]

After the first couple of videos I watched on your channel, I then push the like button of next videos before seeing it.. you're truly a great instructor, I sincerely thank you and I wish you the best in life..

[@TechnoSan09]

THE BEST tutorial online !!!! most would just spit out common theoretical facts about TCP and shows the generic diagram "SYN, SYN ACK, ACK" thats it! this is the only video that explains the whole TCP working fully and clearly bravo mate, became a life time sub for you

[@cslb38]

Fantastic work here as always Ed. Its really a shame that millions of tubers aren't into networking. For those who are lets help share these amazing vids. Looking forward to the course!

[@PracticalNetworking]

If only ;) Thanks either way for the kind words & support.

[@wallysonruan]

I had to stop mid video to congratulate you on this one. The broken down ideas along with the visuals and your clear explanations make this video so much easy to follow along and it never ceases to be interesting. Kudos to you and thank you very much for putting so much effort into this content and sharing it.

[@ErrolSimmonds-fm7bn]

I think it's only fitting that I start off by saying, BRILLIANT!!!! Complicated brought down to Simple. I've always been curious as to how these numbers appear in Wireshark. Hopefully we have a lot more KZbinrs paying attention to this video. You have set the bar extremely high. Thank you and I look forward to more great content!!!!

[@PracticalNetworking]

[@cadsticcadsticc1322]

Seeing what I am able to understand, proves you can teach an old dog new tricks. Thank you for making this topic user friendly.

[@amlananupam1901]

Wow, this video is a gem! Your presentation on TCP connections is top-notch. The clarity in explaining the complex concept of TCP really stands out. I appreciate how you break down the topic in such an understandable way. It's evident that a lot of effort went into making this, and it's greatly appreciated! Kudos to you!

[@PracticalNetworking]

Thanks for the kind words and recognizing the effort it took to put this together =)

[@jaysongalicia8142]

TCP is one of those topics that is super easy to learn but hard to master because of its depth. You can fix TCP-level errors if you learn TCP fundamentally. I've been learning Wireshark recently, and TCP topics are confusing. This video helped me understand some confusing topics. thank you!!

[@PracticalNetworking]

Hi Jayson, absolutely! Learning the fundamentals well is critical. Glad you enjoyed this video! Cheers.

[@AnantaAkash.Podder]

I swear this is the Most Detailed Video for TCP Connection inner-working... Thanks for the so much detailed Explanation ❤️

[@jimboelterdotcomm9153]

I've seen video breakdowns of TCP before, but this is perhaps the best I've encountered. Great job!

[@cait3235]

Your videos have been so incredibly helpful to actually understand these concepts, thank you for explaining things so clearly!

[@krazydji]

Thank you, this is truly one of the best courses I have listened to. Clear, precise, instructive. THANKS

[@PracticalNetworking]

Cheers, Krazydji! Glad you enjoyed it =)

[@suave9901]

Some people are just called and born to do certain things. Yours is certainly teaching mate! I watch these videos as a refresher on certain concepts, but I must say you blow it out of the park! More power to you! Keep them coming pls!

[@venubabu2089]

Excellent explanation about TCP ..by breaking it down u make it easy and simple for us to watch and learn..Tq

[@paca3107]

yeees, so glad that yt algorithm gave me this video

[@PKJamal-b5q]

I just watched 5 mins of your video, this most complicated concept is start making sense. Thank you so much this video.

[@PracticalNetworking]

Glad you're enjoying this video =) I worked soo hard on the TCP lesson.

[@132131313100]

I'm a software engineer who studied CS in uni, but I somehow graduated without taking a proper networking class. Now that I'm working towards a SRE position, your videos has been immenselly helpful like I can't emphasize it enough. Thanks for your hard work! Easily my favourite channel rn

[@michaelfoley7991]

I was a dev for about 10 years before I switched over to net eng. I discovered that devs have no understanding of networking and networkers have no understanding of development. I was blown away at just how insulated development is from the necessities of transmission. Heck, when I finished my CS, I still didn't know what a port was because it never came into play with any software I created. The closest I ever had to do was build a WiFi connector back in 1999 because there wasn't any sort of connector at that point for the type of work I was in.

[@UnixBro]

Do you think that a software need a certificate like CCNA to become a good SRE ? Thanks.

[@UnixBro]

@@michaelfoley7991 Do you think that a software need a certificate like CCNA to become a good SRE ? Thanks.

[@anuragdixit87]

ED when i started my career in network domain...senior people always said just read todd lammle 's book for CCNA ...each word having making sense even it is true at inital level ..but now i will say each word in this vedio make sense as well as very important. Every person who belongs to infra team must go via this video.. Very informative, much cleared in very short time .. Thank you ED for such a video 😊😊

[@PracticalNetworking]

Thanks for the kind comment, =) I'm thrilled to hear you've enjoyed this video and compare me to "the greats" like Todd Lammle. =)

[@felipica]

best video about tcp ive ever seen in my life

[@TheSony7up]

The best is Ed. He does a remarkable job of simplifying complex technologies for us by breaking them down into manageable chunks.

[@PracticalNetworking]

[@nataliarutecka7438]

Dziękujemy.

[@PracticalNetworking]

You're very welcome. Thank you again for supporting the channel. Much appreciated!

[@rudranahak8067]

I am from india ,just interested in networking and your videos were my building ground,before starting my undergraduate journey ,still no completed ,and I will meet you in person and thank you someday for you excelent teaching sir.

[@finnwarner8573]

I rarely comment on videos, but this was fantastic! Well done.

[@PracticalNetworking]

Thank you FInn. I appreciate you taking the time to leave a comment and that you enjoyed this video. Cheers!

[@emiliokimotho]

Best networking explanations ever. I am becoming addicted to this channel.

[@PracticalNetworking]

Excellent, Emilio. Of all the addictions you could have, I imagine this is the least unhealthy ;) Glad you're getting a lot out of this content.

[@ramsfo]

Thank you so much, Sir! What a Phenomenal 'teaching' skill you possess, Ed. Mind blowing and this 44 minutes session barely felt like it. BTW, I am 'not' a technical engineer - technical program manager and you made me understand this 12 methods to understand TCP supremely well ever in my 26 years of work experience :)). Salute and a lot of respect to you. Excellent stuff!!

[@swapnilthawari7314]

Hats off Ed. Truly your a great teacher.

[@PracticalNetworking]

Thank you, Swapnil!

[@vincecater723]

Another brilliant video about TCP connection!

[@PracticalNetworking]

Thank you for supporting the channel =)

[@rookyere]

The best tcp video I've watched so far - vivid and systematic. Looking forward to the masterclass. 👍

[@eyaGHrd]

please finish these awesome series i just can't understand it from nobody else but you , you simplified it and made it more enjoyable , thanks for your efforts and we are waiting for more 🤩😍😍😍😍

[@yasirhamid9043]

I firmly believe this is the finest educational video I have came across. Thank you very much for creating such excellent content.💯💯💯💯💯💯💯💯💯💯

[@surendras5853]

Joined this course today... Very Excited to channel my efforts in right direction.. Ed.. you are the modern GURU..

[@PracticalNetworking]

Thank you, Surendra! Welcome to the course !

[@shahinuddin4418]

Finally I understood the complex concept. Thanks a lot to make the tough topic simple for me.

[@claudiusdsouza2379]

So so clear and to the point explanation. Thank you for this video I understood TCP at the core.

[@m.ardaeren]

🎯 Key Takeaways for quick navigation: 00:00 🌐 *Introduction to TCP and Lesson Overview* - TCP has been the core of internet communication for 40 years. - Exploring 12 key ideas to understand TCP better. - Focus on TCP header fields: sequence number, acknowledgment number, and window. 02:59 📊 *Understanding Sequence Numbers and Acknowledgments* - Sequence number tracks sent bytes; acknowledgment number tracks received bytes. - Sequence and acknowledgment numbers represent bytes, not packets. - Illustration of the relationship between sequence, acknowledgment, and data packets. 06:50 🔄 *Handling Dropped Packets in TCP* - TCP uses re-transmission timeout for dropped packets. - Retransmission occurs if acknowledgment is not received within the timeout. - Efficient handling of dropped packets in both directions. 09:54 ⏰ *Delayed Acknowledgments in TCP* - TCP receivers use delayed acknowledgments to optimize acknowledgment frequency. - Acknowledgments are sent every other received packet or within 500 milliseconds. - Ensures efficient use of network resources. 12:25 🚦 *Window Size in TCP Flow Control* - Window size limits data sent before waiting for acknowledgment. - Sender adjusts based on the receiver's window size. - Illustration of how window size influences data transmission. 16:35 🔄 *Dynamic Window Size and Flow Control* - Window size is sent in every TCP segment. - Window size can be updated dynamically during the connection. - TCP flow control adapts to optimize data transfer rates. 19:19 ↔️ *Bi-Directional TCP: Dual Sequence and Acknowledgment Numbers* - Both sender (Alice) and receiver (Bob) have their sequence and acknowledgment numbers. - Each party independently tracks what it sends and receives. - Bi-directional nature of TCP communication. 22:31 🔄 *TCP Bi-Directional Data Flow* - TCP is bi-directional with both parties having independent secret sequence numbers. - Understanding sequence numbers and acknowledgment numbers is crucial for TCP troubleshooting. - Illustration of sequence and acknowledgment numbers in a one-directional TCP conversation. 23:57 🎲 *Initial Sequence Number (ISN) in TCP* - TCP connections start with each sender randomly choosing its initial sequence number (ISN). - The importance of sharing ISNs before actual data exchange through the three-way handshake. - Example with Alice choosing ISN 1000 and Bob choosing ISN 3000. 25:05 🤝 *Three-Way Handshake in TCP* - Every TCP conversation starts with a three-way handshake. - Explanation of the four events within the three-way handshake: SYN, SYN-ACK, ACK, and the second SYN-ACK. - How sequence and acknowledgment numbers are exchanged during the three-way handshake. 28:58 🪟 *Window Size in TCP* - The window size field in the TCP header determines the starting size of the sender's buffer. - Both parties, Alice and Bob, set their initial window sizes during the three-way handshake. - Dynamic adjustment of window sizes throughout the connection. 31:46 🛑 *Two Methods of TCP Connection Closure* - TCP has two methods to close a connection: graceful and ungraceful. - Idea number 10 introduces the graceful closure using FIN flags. - Overview of the four events in the graceful closure sequence. 32:56 🎭 *Graceful Connection Closing in TCP* - In a graceful connection closing, one side signals the end with a FIN, and the other acknowledges. - Detailed four-step sequence: FIN-ACK, ACK, FIN, and ACK. - Illustration of the sequence and acknowledgment numbers in a simulated closure. 39:52 🚫 *Ungraceful Connection Closing with RST* - Idea number 12 explores ungraceful connection closing using the RST (reset) flag. - The RST flag is used to terminate a connection when something goes wrong. - Explanation of how parties forget everything about the connection after RST. 42:13 🌐 *Next Steps and Future Courses* - The video concludes with three potential paths for viewers. - Encouragement to support the creation of a full TCP masterclass with a goal of 100K views. - Announcement of a comprehensive networking course by the creator. Made with HARPA AI

[@somanathsshenoy]

Here I am watching your video at midnight even though i am down with fever and cough. The medicine with high doses should sedate me but i am getting energized seeing your video

[@krkartick]

Excellent video, after going through a ton of videos about TCP on youtube, by far this is the best and simple video that explains the complex TCP concepts very well. Awesome job. Really like your videos. It is the combination of identifying key concepts in an order, visual representation and concise explanation that makes this video standout.

[@K4pitell]

Thank you very much for this video. It helped me a lot. You're a great teacher and I'm glad I found your channel.

[@UCFc1XDsWoHaZmXom2KVxvuA]

Wow this is one of the best lectures in computing ever!!

[@Fredsch08]

Another great job, sir. This is one of the best explanations of TCP protocol. Thanks a lot for taking the time to create such fantastic content.

[@manigandansrinivasan5194]

Excellent ..Never seen complex topic explained simple way....

[@PracticalNetworking]

Glad you enjoyed it =)

[@shujauttali2608]

The easiest Explanation possible. Hats off

[@somewherenorthofthewall]

I don't even know how to express, that your method of explaining is out of this world. I understood each word you said and obviously the topic. I am looking for videos on routing protocols and vpn protocols. I can buy them if they are available.

[@amirsaid]

Dude Great video! I finally have a clear understanding of TCP/ip thanks to your explanations. Keep up the good work!

[@akathul691]

I have no words to appreciate you...simply out of the world ❤

[@barduse]

GOD level explaination.

[@mousamgoswami1184]

Great way of explaining. Totally cleared my concepts 😊

[@rpinto8800]

Hi Ed, thanks for the content, I have a request could you please make a paid course on BGP in depth. You are an amazing teacher, I like your teaching style.

[@vdg83]

Thanks!

[@PracticalNetworking]

Hi Vinay! Thank you so much for supporting this channel. =) It means the world to me that you've enjoyed the content enough to donate with the SuperThanks. Thank you again... and you are _very_ welcome!

[@nemalisridevi7833]

Your channel is gold in network concepts thankyou!

[@bhagyashreeaher7429]

Great content !!! Very helpful Waiting for full series Thanks

[@ashokreddyb7867]

Your pedagogy is simply awesome. Great work. Kudos

[@chezwoods7575]

PHENOMENAL JOB SIR! THANK YOU. So easy to follow and understand. clear and confident information.

[@PracticalNetworking]

You are very welcome

[@criminalgaming4842]

Understood the concept of TCP very well. All credits to you🤝

[@eenteghadi]

It is so pleasurable watching your videos that can rate them as adult content😃 Thank you for sharing your knowledge

[@YaseenAliKhan804]

You are working hard sir. Keep going watching from INDIA

[@PracticalNetworking]

THank you, Yaseen!

[@Synth5069]

deserves more views honestly

[@PracticalNetworking]

;)

[@x0rZ15t]

Love the explanation with visual schematics. Thank you for your awesome work!

[@PracticalNetworking]

You're welcome! =)

[@fastrobreetus]

Sir, you are a true genius! I have learned so much from these videos!

[@iphelper1574]

4:25 are the ack numbers wrong ? The receiver increments the ACK by 1 but in the video shown as it's acking the SEQ number itself.

[@morenokratter669]

Your Channel is awesome! So much Information transmitted with professionalism! Very helpful to understand these things with your explanation. Keep up with your great content. Thank you!

[@itwing9312]

sir your explanation was aaaawesome , thank you sir am preparing this for my interview

[@oleksiistri8429]

now i finally understand some basics of networking, it was always a black hole for me. thank you very much for this amazing course!

[@PracticalNetworking]

You're very welcome

[@nulllogos5846]

Again, you hit it out of the ballpark. Fantastic.

[@rochuolmos]

how do you make it so easy to understaaaaaaaaand? THANKS A LOT. Super clear and simple to understand. Best networking professor around.

[@PracticalNetworking]

Thanks for the kind words =)

[@mikhailshkaralevich574]

What a great explanation about TCP! Thank you!

[@adamstrejcovsky8257]

Absolutely perfect channel! So glad I discovered it. Amazing job!

[@mohamedabdi6419]

Excellent work, as usual, Ed! I'm delighted to have bought the course early on.

[@PracticalNetworking]

[@Anime_with-arts]

This is precious . very clear and mind blowing Knowledge , Thanks is not a complete word Need more in cloud computing please help to know

[@PracticalNetworking]

Yes, that's the plan getting into cloud computing!

[@arisikal2818]

Thanks it was perfect I'm waiting for series of TCP that you have promised

[@useruserus844]

Very cool explanation, for sure need full master class

[@SEYEDLATHIFFAZIL]

Hi Ed, it was very good session. As always you have cleared myth of TCP framework. Eagerly waiting for the second session. Plz upload as soon as possible.. Once again big thanks for your excellent video... eagerly waiting for your second series

[@worldfac1s]

Man, you are awesome! Explanation on a high level! Thank you

[@misha2082]

What a lesson. Such a simple explanation. Kudos!

[@adedejiemmanuel1]

Wow! You're amazing. Always doing the best to get this community in good shape. Thanks. Could you help clarify something, please. Will idea 5 (TCP windowing) override idea 4 (delayed acknowledgment) because delayed acknowledgment and window function simultaneously in every data flow?

[@scottspa74]

I had the same question after that segment (pun intended). He DID say the 'ideally, Bob would try to ack every other segment, but that that was left out', so I'm a little curious, too. 🤔

[@PracticalNetworking]

Ha, great question. I was weighing up adding something to speak to this in the video but it was already way too long and I had to trim comment somewhere. I'll explore it more in the full master class. But... since you asked ;) The illustration above showed Alice's window starting full, then slowly decreasing until 0, then Alice stops, then an ACK arrives, and the Window is now full again and the process repeats. This is actually an example of an unhealthy / sub-optimal TCP connection. In reality, what you want is for Alice to start sending as fast as she can... but _before her Window drops to 0_ ACKs start arriving from Bob. This way Alice is sending as fast as she can, and Bob's ACKs are coming in fast enough to prevent Alice's window from hitting 0 (and therefore stopping her transmissions). This would be an "ideal" TCP connection. Note that the illustration above is a TCP connection with effectively 0 latency... a real TCP connection will have latency (time delay between sender and receiver). This latency is what would account for Alice being able to send (say, packets 1-10) before she receives Bob's acknowledgement for packets 1 & 2. Then when she sends 11/12, she gets Bob's acknowledgement for 3 & 4. And so on. Hope this clarifies =)

[@PracticalNetworking]

Hi Scott. I answered Azza's comment. Just leaving you a reply so YT gives you the notification =) Cheers !

[@scottspa74]

@@PracticalNetworking super glad you tagged me in this, thanks, Ed. Also, I became an early founder today 👍, super excited to see the new content and the addition of cloud. (I'm in a project right now where I'm supposed to be doing cloud risk assessment 3rd party and have very little idea what I'm doing (it's a sort of mock corporate C-level internship type thing I got sort of roped into and am way over my head)).

[@nobody2anybody]

Thanks ed, waiting for your full TCP and UDP series ...

[@dustcore]

Ed thanks for the great break down. This definitely helped improve my understand of how TCP works.

[@PracticalNetworking]

Hi WemDizzle, glad you enjoyed this one too. Cheers!

[@gnikhil1987]

Gold Standard video by Ed

[@giorgioamato6176]

Hi Ed, let me say that your clarity in explanation is terrific. Many thanks for all the effort you put in your content. A quick question: does the window size equals to the MSS? Regards

[@PracticalNetworking]

Thanks for the kind words. You're very welcome. No, the MSS is different. The MSS is a "per packet" maximum, where as the Window Size is a measure of the "maximum data that can be sent without an acknowledgement"

[@bethankfultogod4538]

Thanks for breaking down TCP to easily understand.