As a 20-year veteran of working as a network engineer, currently on the backbone for Super Huge Major Telecom, Inc., I heartily endorse this video. It is as succinct, accurate, and accessible as anything I've ever seen.
As someone who's been in the IT industry in one form or another for 25 years I completely agree. I still don't understand network routing over large numbers of nodes though - no matter how many times it's explained to me :-).
Yes indeed, I too found this obvious mistake a bit peculiar. But I guess it's an approximation that comes with the fact that they didn't have time to talk about private adresses. This series is still absolutely brilliant imho
Two Professors with PhDs in computer science spent 6 hours in lectures trying to explain this in my Master's lectures. You guys did it in 12 mins, phenomenal!
The video is totally worth watching! Now i get it: IP - is simply what and where to send UDP - on top of IP provides ports and packaging but does not ensure the delivery, just informs when the data is corrupted TCP - on top of IP also provides ports and packaging, but insures the delivery (thus increasing the network load)
Wow, so much work has been put into this video, and all for the purpose of spreading knowledge didactically! You guys are awesome, please keep up the excellent work!
I've been computer science since childhood (for about 25 years now) and I haven't seen such a great explanation of Internet and especially ISO/OSI standards. However I had take exams of these during my university years. Thanks for making this video and please make more videos like of this. :)
I know absolutely nothing about computers besides clicking the thingy to get the stuff and thought it was just magic but I love this series and have binge watched it all. Now I actually have a basic understanding on how all the components do relatively simple jobs to make everything happen and why things are the way they are. Now I just think it's magic that it was thought up by somebody in the first place. Awesome show and please keep them coming
I am now 38 years old and I am learning Python. I tried to learn programming early, but despite all my efforts this opportunity was not given to me in my country. Despite all the obstacles I have never given up on this dream and now I am more motivated than ever to learn from the precious help of the internet. Luckily there are many bright people here who kindly help anyone looking to learn computing. Although very difficult, I hope that one day I will become a programmer.
Moysés Gurgel So sorry that you didn't get the opportunity earlier; I was fortunate enough to have a hobbyist dad who pushed me into programming at age eight. This was in the Java 1 days.
Moysés, congratulations on your choice to learn (what seems to me) the most useful language of these years! I can only warmly recommend the Socratica channel for their Python introductory course, it's short and well explained! (In particular, I can sadly no longer recommend LPTHW which isn't available for free online any longer...)
Same here, wanted to learn computer science since 14 but such courses weren't available in my country. I couldn't afford to go abroad to learn CS and had to be good at math which I wasn't. Self taught all the way, 32 now and I am getting closer.
@@rosellecarmen2224 You mean computer science courses at age of 14 or after ? I'm actually in computer science bachelor 1rst year in my country. It's extremely accessible (by education) here.. Don't worry that almost everyone are struggling in analysis course, even mathematicians.
This video sums up my entire networking course in a thousandth of the time. Truly amazing stuff, I absolutely love the level of detail that goes into these videos!
I'm taking CCNA (Cisco Certified Networking Associate) and this video would have really been helpful as an introduction to the course. The Cisco site really should link to your video.
Agreed. When I started working at the Cisco TAC in 1996, I was told to get a particular book and read it cover to cover. That was my training in networking (I'd been educated as a programmer - not even close.) Two years later, I was a CCIE and was proctoring the lab test - working in TAC kinda had that effect back then. I can still name that book - "Internetworking with TCP/IP", volume 1, 3rd edition, by Douglas Comer. I still have my copy somewhere around here.... Some say, though, that in later editions Comer "sold out" to Microsoft by introducing some spurious elements to the OSI model. Sad.
Russ Emerson These days I point people to ISP Essentials by Barry Raverndran Greene and Philip Smith on Cisco Press. It’s got most of the practical stuff in it without a lot of fluff.
Carrie Anne talks very fast! She also knows her stuff. I’ll need to watch these lovely well constructed videos several times to really take on board the information but I’ve love every second! Thanks for producing such clear concise and highly enjoyable videos. Magic. 👍
"Hi, I'd like to hear a TCP joke." "Hello, would you like to hear a TCP joke?" "Yes, I'd like to hear a TCP joke." "Ok, I'll tell you a TCP joke." "Ok, I will hear a TCP joke." "Are you ready to hear a TCP joke?" "Yes, I am ready to hear a TCP joke." "Ok, I am about to send the TCP joke. It will last 10 seconds, it has two characters, it does not have a setting, it ends with a punchline." "Ok, I am ready to get your TCP joke that will last 10 seconds, has two characters, does not have an explicit setting, and ends with a punchline." "I'm sorry, your connection has timed out. Hello, would you like to hear a TCP joke?"
This is exceptionally well done. Brilliant animations and love the discussion on abstraction (used a lot in CS topics and something that can add confusion at first but eventually becomes super helpful and you get why its done so much!). Gonna watch all of your vids now. Cheers.
I love this series, thankyou! I'm really hoping at some point you'll took about encryption techniques, and also compression techniques, because I'm learning about both in my own time and they're really interesting.
I love you, you are simply excellent, there are many concepts so hard to understand about the computers, but you can explain them so clearly. Congratulations, this is the best channel I've ever found in youtube.
You are an amazing person sharing this details! Thank you so much for such a great presentation...! If you have this as an online course I am totally in!
UDP does not apply the checksum across the data payload. It only applies to the port numbers and parts of the IP header to make sure the packet didn't go to the wrong place.
4:14 No, it's cleverer than that. The uppermost bits overflow _into_ the lower bits: it's called "ones' complement" or "end-around carry". This is because the values to be summed are not the individual octets but rather _pairs_ of octets treated as 16-bit numbers. Thanks to this clever "ones' complement" hack, it doesn't matter whether your computer is a 386 that thinks of them as little-endian numbers, or an m68k that thinks they're big-endian: each octet carries into the other octet - it's a circle that has no ends to be big or little. There's also _another_ clever hack: the checksum isn't just the sum of the packet data, instead it's _minus_ the sum of the packet data. This means that if you want to validate the checksum on an incoming packet, you just add up the _whole_ packet, including the checksum, and if it's valid you should get *zero*. (This turns out to be a big deal for network encapsulation - where your UDP payload is another entire packet with its own IP, UDP etc. headers - because it means you can calculate the outer checksum just by looking at the outer headers, since you know the inner packet with a correct checksum adds up to zero. This is called Local Checksum Offload, and was invented by, erm, _me_. But I think the people who originally designed the Internet Protocol checksum are the ones who really deserve the credit, because it's their brilliant design that made it possible.) 7:29 The main reason for using UDP instead of TCP isn't the ACKs and the bandwidth they use, it's that latency-sensitive applications generally want each individual packet delivered as soon as possible - they don't want new data to be buffered up in the OS just because it's still waiting for some old data that's supposed to come before it but maybe isn't even relevant any more. This rationale applies to everything from video chat (I already displayed that frame with low resolution and glitches, it's too late now to tell me what it should have shown, I want the next video frame ASAP) to financial trading (give me the most recent stock price, I don't care what the price 10 microseconds ago was!). Lag is caused not by ACKs but by waiting for retransmissions and enforcing ordering constraints that - at the application layer - may be totally irrelevant. 9:11 Technically (and yes I'm being pedantic now), the very top of the tree are the _root name servers_, 'a.root-servers.net' through 'm.root-servers.net'. 10:05 Oh no, not the OSI 7-layer burrito. Real-world networking implementations don't look anything like that over-engineered heap (does anyone really understand wtf the Presentation Layer corresponds to in the Internet protocol stack?) The standard protocol stack today combines the physical and data-link layers into Ethernet (attempts to separate them out conceptually founder on the way the data-link part of it gets waaaay too intimate with the physical part). Similarly, some of the network layer's functions are handled by 'layer 4' protocols like TCP or UDP, and some functions that OSI puts in the transport layer are done either by IP or by other layer-3 protocols that go straight on top of Ethernet rather than being wrapped in IP datagrams. Sometimes the layering even differs between IPv4 and IPv6: ARP, which is considered a link layer function, is layered on top of Ethernet, making it network layer; its IPv6 equivalent, Neighbour Discovery, is part of ICMPv6, sent inside IPv6 datagrams, making it technically a transport layer protocol! Certainly the Internet protocol suite _is_ layered, but the trouble with the OSI model is that it's so neat and theoretically elaborated that it _sounds_ like it should be a strict and precise thing, whereas real, working networks are inevitably messy and don't follow neat layering boundaries. See also RFC3439. While the OSI model does give us a few nice names ("Layer 3", "Layer 4", and also (though it doesn't actually define it itself) "Layer 8" for the "user's intentions and behaviour" layer), it shouldn't be taught without a warning that it's basically a cross between numerology and stamp-collecting.
The Cheaterman The Cheaterman Use Google, he did actually invent it... And sure, they couldn't go into crazy detail, but the video definitely had flaws that wouldn't have been hard to fix. The TCP/UDP reasoning is one of them and the OSI thing didn't make a ton of sense to even include
I don't think that you are really the intended audience for this mate. "... it's cleverer than that" - sure. But if you want to have a crash course in how this works, but don't actually intend to work with this stuff it doesn't really matter in detail how a checksum works.
+Simon T Yeah I know I'm not the intended audience, +The Cheaterman I realise they couldn't go into this much depth. I'm trying to provide _additional_ information in the comments for anyone who does want a bit more depth, and also maybe give them ideas for if they ever do a "compsci 201" series like they did with CC World History. I should probably have started my comment with a disclaimer like "notwithstanding the following nitpicks, this was a well-made educational video".
Here's a practical question...why is it not recommended to type sensitive information (passwords, card numbers) on public networks (coffee shop or airport), like how exactly can someone view that info?
You forgot Layer 8: the User layer. If an network support guy says someone had a Layer 8 issue, that's a nice way of saying the user was being an idiot. The idea can be extended with the organisation the user was a part of being a ninth layer, and the laws of the country it operates in being a tenth.
The OSI model doesn't really apply to the TCP/IP stack, hence it having it's own model. The session layer an above are just considered "Application layer" because how they are used and implemented is *very* application specific. DNS, for example, has no session layer.
Yes it does. TCP is layer 4 and 5. IP is layer 3. DNS has no session layer because it is an application layer protocol. It uses UDP as its transport. UDP doesn't have a strict session management. I'm sure you know all this because the OSI is intended to model and make it easier to understand where everything fits together, and isn't a protocol or even meant to be an exact representation of what's going on. Stop trying to snipe. No one uses the TCP model.
I hate to say it, but that first line in the output from traceroute is not *her* computer, but the address of the gateway it's connected to though it's local ethernet (or the Wifi hotspot).
Hmm... I tried doing traceroot for dftba.com from Serbia. It took me only 8 hops and my latency was lower than Carrie Anne’s. Didn’t expect I had such a good connection.
why not make an alternate TCP where the transmitter just sends the whole thing and the receiver simply sums which packets didnt come in and rerequest those until the whole thing is complete. I know this wouldnt work with all applications, but most will work just fine without clogging the bandwidth with so many requests and acknowledgements
Jokes on you- I didn’t stream this. I sent someone to download this video, burn it on a disk, then play it for me off an old portable DVD player. Now he’s writing this comment for me. Checkmate, computer lady.
is this the last episode in this great series on Computing Science? Its been good viewing them, look forward to others in your series eg the history one
I am assuredly behind the times on this observation, but her use of "the Doopleydoo" is by far the most apparent John thing I've experienced this week.
Hopefully they will run analog tv waves besides digital to prevent the Skype syndrome you described, plus the CD skip and "no content this channel" blank screens. I'd prefer analog snow to no tv. Country is nice...if I have a tv 😋
As a 20-year veteran of working as a network engineer, currently on the backbone for Super Huge Major Telecom, Inc., I heartily endorse this video. It is as succinct, accurate, and accessible as anything I've ever seen.
As someone who's been in the IT industry in one form or another for 25 years I completely agree. I still don't understand network routing over large numbers of nodes though - no matter how many times it's explained to me :-).
same
same
🐢
🐢
🐢
Yes indeed, I too found this obvious mistake a bit peculiar. But I guess it's an approximation that comes with the fact that they didn't have time to talk about private adresses. This series is still absolutely brilliant imho
would you mind elaborating about the mishaps, so that those who are not beginners could get the right information too. TIA
Two Professors with PhDs in computer science spent 6 hours in lectures trying to explain this in my Master's lectures. You guys did it in 12 mins, phenomenal!
The video is totally worth watching!
Now i get it:
IP - is simply what and where to send
UDP - on top of IP provides ports and packaging but does not ensure the delivery, just informs when the data is corrupted
TCP - on top of IP also provides ports and packaging, but insures the delivery (thus increasing the network load)
Wow, so much work has been put into this video, and all for the purpose of spreading knowledge didactically! You guys are awesome, please keep up the excellent work!
+
If you turn off your ad block, you'll see there's another nefarious sinister reason.
I've been computer science since childhood (for about 25 years now) and I haven't seen such a great explanation of Internet and especially ISO/OSI standards. However I had take exams of these during my university years. Thanks for making this video and please make more videos like of this. :)
HEILLL NAAA www.studytonight.com/computer-networks/complete-osi-model
Just google it :)
I know absolutely nothing about computers besides clicking the thingy to get the stuff and thought it was just magic but I love this series and have binge watched it all. Now I actually have a basic understanding on how all the components do relatively simple jobs to make everything happen and why things are the way they are. Now I just think it's magic that it was thought up by somebody in the first place. Awesome show and please keep them coming
I am now 38 years old and I am learning Python. I tried to learn programming early, but despite all my efforts this opportunity was not given to me in my country. Despite all the obstacles I have never given up on this dream and now I am more motivated than ever to learn from the precious help of the internet. Luckily there are many bright people here who kindly help anyone looking to learn computing. Although very difficult, I hope that one day I will become a programmer.
Moysés Gurgel Keep on there friend. Do what your heart desire. You will get there.
Moysés Gurgel So sorry that you didn't get the opportunity earlier; I was fortunate enough to have a hobbyist dad who pushed me into programming at age eight. This was in the Java 1 days.
Moysés, congratulations on your choice to learn (what seems to me) the most useful language of these years! I can only warmly recommend the Socratica channel for their Python introductory course, it's short and well explained! (In particular, I can sadly no longer recommend LPTHW which isn't available for free online any longer...)
Same here, wanted to learn computer science since 14 but such courses weren't available in my country. I couldn't afford to go abroad to learn CS and had to be good at math which I wasn't. Self taught all the way, 32 now and I am getting closer.
@@rosellecarmen2224 You mean computer science courses at age of 14 or after ? I'm actually in computer science bachelor 1rst year in my country. It's extremely accessible (by education) here.. Don't worry that almost everyone are struggling in analysis course, even mathematicians.
Everyone involved in this : thank you ! This series is AMAZING !
This video sums up my entire networking course in a thousandth of the time. Truly amazing stuff, I absolutely love the level of detail that goes into these videos!
But they have to lengthen the course to get the most money out of you. See crash course Economics 😁
3:57 "Yo! :)" (in ASCII/UTF8)
Who knew so much thought went into distributing cat videos?
Best distributed by cat5 cables. Make sure you use your mouse to click on it 😁🐈🐀
I'm taking CCNA (Cisco Certified Networking Associate) and this video would have really been helpful as an introduction to the course.
The Cisco site really should link to your video.
Barnard Rabenold you have your work cut out for you if you think this would have been helpful for getting your CCNA.
I would hope you would have enough of a grasp on networking to shoot for CCNA to not have this be anything but a review. This is Network+ level stuff.
That's basically what I said. This video pretty much was a review for me, but would have been very helpful when I first started.
Agreed. When I started working at the Cisco TAC in 1996, I was told to get a particular book and read it cover to cover. That was my training in networking (I'd been educated as a programmer - not even close.) Two years later, I was a CCIE and was proctoring the lab test - working in TAC kinda had that effect back then.
I can still name that book - "Internetworking with TCP/IP", volume 1, 3rd edition, by Douglas Comer. I still have my copy somewhere around here....
Some say, though, that in later editions Comer "sold out" to Microsoft by introducing some spurious elements to the OSI model. Sad.
Russ Emerson These days I point people to ISP Essentials by Barry Raverndran Greene and Philip Smith on Cisco Press. It’s got most of the practical stuff in it without a lot of fluff.
The production of this is amazing, explained so well from scratch. I am honestly impressed, thank you so much for this!
As a non-cumputer person, thank you very much for this whole series !
lol cumputer
This video single-handedly made me understand more about networking than a whole year of my university module.
Carrie Anne talks very fast! She also knows her stuff. I’ll need to watch these lovely well constructed videos several times to really take on board the information but I’ve love every second! Thanks for producing such clear concise and highly enjoyable videos. Magic. 👍
This series has been extremely informative and super easy to process.
can't say I've heard of it
it's like a net but with inter
I could tell you a joke about UDP, but you might not get it.
I didn't get it.
Can you replay?
Wokka wokka!
Would you like to hear a TCP joke?
"Hi, I'd like to hear a TCP joke."
"Hello, would you like to hear a TCP joke?"
"Yes, I'd like to hear a TCP joke."
"Ok, I'll tell you a TCP joke."
"Ok, I will hear a TCP joke."
"Are you ready to hear a TCP joke?"
"Yes, I am ready to hear a TCP joke."
"Ok, I am about to send the TCP joke. It will last 10 seconds, it has two characters, it does not have a setting, it ends with a punchline."
"Ok, I am ready to get your TCP joke that will last 10 seconds, has two characters, does not have an explicit setting, and ends with a punchline."
"I'm sorry, your connection has timed out. Hello, would you like to hear a TCP joke?"
I UDP the could of joke out you be tell, but a order might about response.
Informative as always, I love these videos, I learned more here than I learned in my entire 12 years of school.
This is exceptionally well done. Brilliant animations and love the discussion on abstraction (used a lot in CS topics and something that can add confusion at first but eventually becomes super helpful and you get why its done so much!). Gonna watch all of your vids now. Cheers.
Thank you very much! This lesson is very usefull for my class (I'm a IT teacher).
I love this series, thankyou!
I'm really hoping at some point you'll took about encryption techniques, and also compression techniques, because I'm learning about both in my own time and they're really interesting.
Conor O'Neill
She already talked about data compression a couple of weeks ago.
Easily understood such a complex topic! Many thanks.These videos are gold.
Samuel D. Reynolds.
Wow, this video from Crash Course is very easy to understand. As a beginner, this course will help me a lot. Thank you!
Doing the world a great service with all you offer CrashCourse! You have my support.
Thank you!
But I thought the Internet was a black box with a red light on top. MY LIFE IS A LIE.
Oh that reference brings back memories.
DreadKyller it is. She is.lying
+
IT CROWD HOORAY
It is. Everything in this video takes place in a black box at the top of Big Ben
Wow so awesome! Learning this for my internship for computer networking :)
God Bless Crash Course. I'm forever grateful of their services to humankind.
This series is absolutely fantastic!
It is amazing that how you can explain such a complex topic like computer networks clearly and in such a short time!!!
I love you, you are simply excellent, there are many concepts so hard to understand about the computers, but you can explain them so clearly. Congratulations, this is the best channel I've ever found in youtube.
This series is really good.
Excellent performance
Thank you very much.
You are an amazing person sharing this details! Thank you so much for such a great presentation...! If you have this as an online course I am totally in!
Network fundamentals in a nutshell. Definitely going to refer this vid to my pals interested in network administration.
Nobody:
Carrie Anne: *casually sharing her IP address on a 13.7 million subscriber channel*
/s
Thank you soo much for this video. Never really understood the concept of UDP and TCP in college..You explained it really well.
UDP does not apply the checksum across the data payload. It only applies to the port numbers and parts of the IP header to make sure the packet didn't go to the wrong place.
5:41 sounded like rapping for a second
Great episode!! We just learned about UDP / TCP and other network protocols in our IT apprenticeship class.. :)
Thank you Carrie Anne!! ❤❤
Best teaching approach I have found. Thank You.
This series is amazing! Thanks a lot
4:14 No, it's cleverer than that. The uppermost bits overflow _into_ the lower bits: it's called "ones' complement" or "end-around carry". This is because the values to be summed are not the individual octets but rather _pairs_ of octets treated as 16-bit numbers. Thanks to this clever "ones' complement" hack, it doesn't matter whether your computer is a 386 that thinks of them as little-endian numbers, or an m68k that thinks they're big-endian: each octet carries into the other octet - it's a circle that has no ends to be big or little.
There's also _another_ clever hack: the checksum isn't just the sum of the packet data, instead it's _minus_ the sum of the packet data. This means that if you want to validate the checksum on an incoming packet, you just add up the _whole_ packet, including the checksum, and if it's valid you should get *zero*. (This turns out to be a big deal for network encapsulation - where your UDP payload is another entire packet with its own IP, UDP etc. headers - because it means you can calculate the outer checksum just by looking at the outer headers, since you know the inner packet with a correct checksum adds up to zero. This is called Local Checksum Offload, and was invented by, erm, _me_. But I think the people who originally designed the Internet Protocol checksum are the ones who really deserve the credit, because it's their brilliant design that made it possible.)
7:29 The main reason for using UDP instead of TCP isn't the ACKs and the bandwidth they use, it's that latency-sensitive applications generally want each individual packet delivered as soon as possible - they don't want new data to be buffered up in the OS just because it's still waiting for some old data that's supposed to come before it but maybe isn't even relevant any more. This rationale applies to everything from video chat (I already displayed that frame with low resolution and glitches, it's too late now to tell me what it should have shown, I want the next video frame ASAP) to financial trading (give me the most recent stock price, I don't care what the price 10 microseconds ago was!). Lag is caused not by ACKs but by waiting for retransmissions and enforcing ordering constraints that - at the application layer - may be totally irrelevant.
9:11 Technically (and yes I'm being pedantic now), the very top of the tree are the _root name servers_, 'a.root-servers.net' through 'm.root-servers.net'.
10:05 Oh no, not the OSI 7-layer burrito. Real-world networking implementations don't look anything like that over-engineered heap (does anyone really understand wtf the Presentation Layer corresponds to in the Internet protocol stack?) The standard protocol stack today combines the physical and data-link layers into Ethernet (attempts to separate them out conceptually founder on the way the data-link part of it gets waaaay too intimate with the physical part). Similarly, some of the network layer's functions are handled by 'layer 4' protocols like TCP or UDP, and some functions that OSI puts in the transport layer are done either by IP or by other layer-3 protocols that go straight on top of Ethernet rather than being wrapped in IP datagrams. Sometimes the layering even differs between IPv4 and IPv6: ARP, which is considered a link layer function, is layered on top of Ethernet, making it network layer; its IPv6 equivalent, Neighbour Discovery, is part of ICMPv6, sent inside IPv6 datagrams, making it technically a transport layer protocol!
Certainly the Internet protocol suite _is_ layered, but the trouble with the OSI model is that it's so neat and theoretically elaborated that it _sounds_ like it should be a strict and precise thing, whereas real, working networks are inevitably messy and don't follow neat layering boundaries. See also RFC3439. While the OSI model does give us a few nice names ("Layer 3", "Layer 4", and also (though it doesn't actually define it itself) "Layer 8" for the "user's intentions and behaviour" layer), it shouldn't be taught without a warning that it's basically a cross between numerology and stamp-collecting.
"invented by me"? Otherwise, great comment, although I'm sure you realize they couldn't go into such depths in the video. :-)
The Cheaterman The Cheaterman Use Google, he did actually invent it... And sure, they couldn't go into crazy detail, but the video definitely had flaws that wouldn't have been hard to fix. The TCP/UDP reasoning is one of them and the OSI thing didn't make a ton of sense to even include
7:29 You say it isn't the ACKs and then go on to explain why it is the ACKs.
9:11 You didn't just start being pedantic here.
I don't think that you are really the intended audience for this mate. "... it's cleverer than that" - sure. But if you want to have a crash course in how this works, but don't actually intend to work with this stuff it doesn't really matter in detail how a checksum works.
+Simon T Yeah I know I'm not the intended audience, +The Cheaterman I realise they couldn't go into this much depth. I'm trying to provide _additional_ information in the comments for anyone who does want a bit more depth, and also maybe give them ideas for if they ever do a "compsci 201" series like they did with CC World History. I should probably have started my comment with a disclaimer like "notwithstanding the following nitpicks, this was a well-made educational video".
Here's a practical question...why is it not recommended to type sensitive information (passwords, card numbers) on public networks (coffee shop or airport), like how exactly can someone view that info?
If it is not a secure HTTPS session, eavesdropping devices inserted into the network will reveal unencrypted information.
Better explanation than the one I got from my professor at the University of Minnesota lol
Anthony Phan LOL
I'm in love with this channel!!! The way you represent every topic is so clear. Thank you so much Carrie Anne and PBS😁
man i had problems understanding the OSI system and this video explains it in the best way possible in 10 minuets!! double like
This was published at the perfect time because we're learning about this in class right now
Mind-blowing Course
Way to go Carrie Anne!
and then you start working with websockets which add another layer of packets on top of the application layer packets.
LEARNING.. SO.. MUCH...! Also, overwhelmed af.
I love this , thank you🙏🏼 , all of you
You forgot Layer 8: the User layer.
If an network support guy says someone had a Layer 8 issue, that's a nice way of saying the user was being an idiot.
The idea can be extended with the organisation the user was a part of being a ninth layer, and the laws of the country it operates in being a tenth.
Wow, thank you! Subscribed and liked immediately!!! :)
ISP...
ISP . . .
_ISP_ . . .
*Isp*
*specific impulse*
*KERBAL SPACE PROGRAM*
I like your use of the 8 x 12 form of the Windows built-in Raster Command Line Font for these videos (because I just think that font is cool).
What a weird coincidence, my networking class just went over this today.
The OSI model doesn't really apply to the TCP/IP stack, hence it having it's own model. The session layer an above are just considered "Application layer" because how they are used and implemented is *very* application specific. DNS, for example, has no session layer.
Yes it does. TCP is layer 4 and 5. IP is layer 3.
DNS has no session layer because it is an application layer protocol. It uses UDP as its transport. UDP doesn't have a strict session management.
I'm sure you know all this because the OSI is intended to model and make it easier to understand where everything fits together, and isn't a protocol or even meant to be an exact representation of what's going on.
Stop trying to snipe. No one uses the TCP model.
I can't believe I had a class on computer networks in college that didn't teach me anything nearly as efficiently as two 10-minutes youtube video.
Thank you
I love this video, but the transition noise was a bit distracting. You go, girl xo
this is eye-opening
Again, the Internet is really, really great.
I hate to say it, but that first line in the output from traceroute is not *her* computer, but the address of the gateway it's connected to though it's local ethernet (or the Wifi hotspot).
Amazing video, thanks guys!
Hmm... I tried doing traceroot for dftba.com from Serbia. It took me only 8 hops and my latency was lower than Carrie Anne’s. Didn’t expect I had such a good connection.
love this channel so much, really appreciate the efforts. Keep up the great work. And DFTBA!!!!!!
why not make an alternate TCP where the transmitter just sends the whole thing and the receiver simply sums which packets didnt come in and rerequest those until the whole thing is complete. I know this wouldnt work with all applications, but most will work just fine without clogging the bandwidth with so many requests and acknowledgements
Incredible this helped me a lot
Hope to see a knowledge graph of this entire series
0:15
8.4M views -> 17 thumbs down. Well that's being optimistic.
Awesome.
As an IT guy I got it, and it was good for me to see it again, but for the lay person I think they would say "Whaa??"
Might be worth noting that your home "router" is actually a switch, a router, and wireless AP combined.
So good. I learn so crazy much
excellent video
Thank you for all the knowledge. Learned a lot.
Awesome job explaining this 👏
Jokes on you- I didn’t stream this. I sent someone to download this video, burn it on a disk, then play it for me off an old portable DVD player. Now he’s writing this comment for me. Checkmate, computer lady.
1:16 hahaha that caught me so off guard!
Wish these were around 10 years ago!
Very good video! Even I understood it, Thank you
“You computer may not know which application to give the data to, Skype or call of duty? “That is an insult to Reddit
is this the last episode in this great series on Computing Science? Its been good viewing them, look forward to others in your series eg the history one
8:19 "It's like the phone book for the Internet"
Zoomers: Phone book? What is that?
Hank got that rizz
*mac oss*
It's like gooey all over again...
Have to say something before this video blows up. *that's pretty good*
This video is amazing! Thank you
Does this UDP-checksum perform an end-around carry?
Could you make a course on statistics as well? It would be really useful.
1:40 - uh oh.. prepare for some spam packets.
I am assuredly behind the times on this observation, but her use of "the Doopleydoo" is by far the most apparent John thing I've experienced this week.
realy helpfull to learn to cisco ccna in that way, thanks :)
Lol now I must watch all these 12 min videos for my project of my English course
Hopefully they will run analog tv waves besides digital to prevent the Skype syndrome you described, plus the CD skip and "no content this channel" blank screens. I'd prefer analog snow to no tv. Country is nice...if I have a tv 😋