Introduction to Computer Network Series | Chai aur computer network — Transcript

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1. 0:00Yes. It's the era of AI these days.
2. 0:04Everything should revolve around AI.
3. 0:07When we make videos or plan a series,
4. 0:09the first topic that comes up is, "
5. 0:11Since AI is getting so much traction
6. 0:13and people want to see this video,
7. 0:15should we do something around AI or
8. 0:16something around probabilistic system
9. 0:18design?" But sometimes we think, "No,
10. 0:22let's go a step further and discuss
11. 0:25some foundational topics." Now, look,
12. 0:29whether AI comes or not, whatever
13. 0:31happens, no matter how the code is
14. 0:33written, whoever writes it, no matter
15. 0:35what level of interaction, some
16. 0:36fundamentals and foundations will
17. 0:38always remain the same. They're so well
18. 0:41designed that we never think about them
19. 0:43, so we don't get much of a chance to
20. 0:46discuss them because they rarely have
21. 0:48bugs, and you probably never imagined
22. 0:50that bugs exist in them. Yes, they do.
23. 0:53So, when I mention foundations, the
24. 0:55first topic that comes to mind is, well
25. 0:57, some computer-related foundations,
26. 0:59like data structures and algorithms. I
27. 1:02know, data structures and algorithms
28. 1:04have gotten so much hype, partly
29. 1:05because of interviews and partly
30. 1:06because of courses, that we assume that
31. 1:08when we're talking about computer
32. 1:09fundamentals or foundations, we're only
33. 1:11talking about DSA. That's not true. I
34. 1:14agree that DSA is one round of
35. 1:16interviews. Sometimes there are more
36. 1:18rounds. But it's not that engineers
37. 1:20aren't asked anything else, or that
38. 1:22they're not expected to know other
39. 1:24foundations. Another topic is equally
40. 1:27important: computer networks. Now, no
41. 1:30matter who writes the code, it's on
42. 1:31your local host, it goes to the server,
43. 1:33and how many clients will the server
44. 1:34communicate with? Ultimately, all of
45. 1:37this hinges on computer networks. How
46. 1:39does one computer communicate with
47. 1:41another? What are its protocols? How
48. 1:43does this mechanism work? It's equally
49. 1:45important to know all of this. Now,
50. 1:47such series are actually created in two
51. 1:50or three ways. The first method is
52. 1:53where you're presented with a topic or
53. 1:55question and told, "This is the exact
54. 1:58answer. Study this much for the
55. 1:59interview; you don't need to study more
56. 2:00." That's fine. Then there are topics
57. 2:04created, like, "Look, here's a topic,
58. 2:05I'm giving you three bullet points.
59. 2:07Memorize it for the exam and bring it.
60. 2:09That's it." That's fine, because
61. 2:11there's a requirement for that too.
62. 2:13This isn't either of those series. This
63. 2:16series is for curious engineers who
64. 2:18truly want to understand computer
65. 2:20networks as engineers. They want a
66. 2:22detailed discussion of what it is, how
67. 2:24it works, and how much networking
68. 2:26should a software engineer study, and
69. 2:28how important it is. We wanted to cover
70. 2:32all of that in this series, and we have
71. 2:34. These videos don't prepare you for
72. 2:36any CCNA or computer network exams.
73. 2:38They go beyond that. How much knowledge
74. 2:41a fundamental engineer needs, and how
75. 2:43to treat a curiosity. How much detail,
76. 2:46depth, and practical examples using
77. 2:48Wireshark are all included. All of that
78. 2:51is included in this computer network
79. 2:53series. Now, this series is a little
80. 2:56unique because the most difficult part
81. 2:58of this series was finishing it. Yes,
82. 3:00sir. And you know, until the series is
83. 3:02finished, I don't make any
84. 3:04announcements, not even a single word,
85. 3:05until it's complete. This one is a
86. 3:08little unique. We've already made about
87. 3:1125-30 or 25-26 videos of it. We're
88. 3:13rolling them out slowly. They're mostly
89. 3:15in the editing process. Many of them
90. 3:17are already edited. That's why I'm
91. 3:19bringing this series to life. But will
92. 3:21this series end here? That's the most
93. 3:24interesting part. No, we'll definitely
94. 3:26release all the videos we initially
95. 3:27planned for the first phase. It has a
96. 3:30very long and impressive playlist.
97. 3:32However, there are many computer
98. 3:33network topics that later make us think
99. 3:35, "Oh, this one, and this one, could be
100. 3:38introduced a little bit." So, maybe
101. 3:40we'll keep this series open-handed so
102. 3:42that if we come across other topics
103. 3:45later, we can add them on. But it's not
104. 3:48like we're going to run this forever.
105. 3:50Because I personally believe that the
106. 3:52end of things is more important than
107. 3:54the beginning. Especially in the course
108. 3:57playlists, I'll definitely inform you
109. 4:00when our first phase is over. After
110. 4:02that, there will be only a few videos.
111. 4:04It's not like there will be 50 videos
112. 4:05after that. That won't happen. But you
113. 4:07can assume that this series will run at
114. 4:09an initial level, with between 25 and
115. 4:1126 videos. And the length of the videos
116. 4:14also varies slightly because we've
117. 4:16divided them topic-wise. Some videos
118. 4:18are 30 minutes long, while others end
119. 4:21in 5-7 minutes. So, there are different
120. 4:23takes, so you'll get the full idea. But
121. 4:25rest assured, our promise with this
122. 4:28series is that you'll receive
123. 4:30experienced knowledge. Not just
124. 4:32knowledge, but the experienced
125. 4:34knowledge that we and our team have
126. 4:36learned and understood about computer
127. 4:38networks over the years, we'll share it
128. 4:40all with you here. It took a lot of
129. 4:42hard work to create this. A lot of
130. 4:44effort. So, our only request is that we
131. 4:46don't have a high comment target. The
132. 4:49comment target for each video will be
133. 4:51100 videos. I'm giving you an
134. 4:52introduction to just the first video.
135. 4:54After that, you'll simply watch the
136. 4:55videos. Don't worry about it. But it's
137. 4:57important to come and talk a little.
138. 4:59It's important to set a comment target.
139. 5:01And if you still feel like it's
140. 5:03important to mention the date you're
141. 5:05watching the video, the first thing you
142. 5:07should know is the date. Furthermore,
143. 5:09if you feel like we should touch on
144. 5:11this topic further or elaborate on it a
145. 5:12little more, if you understood this a
146. 5:14little less, or this a little more,
147. 5:15please let us know in the comments. We
148. 5:17analyze the comments for each video and
149. 5:20, based on that, we create topics and
150. 5:23videos. So, that was just a brief
151. 5:26introduction. So, welcome to Computer
152. 5:29Networks. One thing you should
153. 5:31definitely do is share it with all your
154. 5:33friends. Share it on social media as
155. 5:35well. Twitter, Lindin, wherever you're
156. 5:37active, saying, "Yes, finally, how is a
157. 5:39computer network from an engineer's
158. 5:41perspective?" Let's read that too.
159. 5:43Curiosity-focused. Not exam-focused.
160. 5:45Curiosity-focused.
161. 5:47Hello everyone, welcome to the
162. 5:49introduction video of our Networking
163. 5:51series. Okay? So, every day we make
164. 5:53hundreds of HTTP requests when we visit
165. 5:55any website. We go to YouTube, we go to
166. 5:58Netflix. As software developers, we
167. 6:00spin up servers and handle requests. We
168. 6:03build front ends. From there, we send
169. 6:04requests. Get requests, post requests.
170. 6:06Right? We do all these things without
171. 6:08realizing that network communication is
172. 6:11crucial in all of this. Right? That's
173. 6:13why understanding networks as a
174. 6:15software engineer is very, very
175. 6:17critical. So, whenever you watch videos
176. 6:19, series, send requests from the front
177. 6:22end, how they travel over the network,
178. 6:24what operations are performed on it,
179. 6:27understanding all of this is nothing
180. 6:29but understanding the network. And in
181. 6:31this playlist, we're going to demystify
182. 6:33that completely. So, let's jump into
183. 6:35the screen. And let's see what topics
184. 6:37we'll be making videos on. So, the
185. 6:39first video we'll have in this playlist
186. 6:41is "What Happens When You Make an HTTP
187. 6:43Request." Yes, because I'm specifically
188. 6:46creating this playlist for software
189. 6:48engineers, those who already have an
190. 6:50idea about servers (front ends) and how
191. 6:52an HTTP server handles requests. But
192. 6:54they don't know what happens underneath
193. 6:55the hood. Whenever you get an HTTP
194. 6:57request, you get an HTTP request. Then,
195. 6:59what happens to that request underneath
196. 7:00the hood? All we know is that we get it
197. 7:02, it reaches the server, and we get a
198. 7:04response. But everything that happens
199. 7:06in between, we'll explore in detail
200. 7:08throughout this playlist. So that's why
201. 7:11I've included the first video so I can
202. 7:13give you an introduction to what
203. 7:15happens when you make an HTTP request.
204. 7:17You may not understand much of what I'm
205. 7:20teaching specifically in this video.
206. 7:22But that's okay because I want to
207. 7:24introduce you to some concepts in this
208. 7:27video, concepts I'll explain further in
209. 7:30future videos. That's why I've placed
210. 7:33this video here, where we'll kind of
211. 7:35touch on the networking part. Okay?
212. 7:37Then we'll slide into networking
213. 7:39fundamentals. Our base, our core of
214. 7:41networking, is the structure of an IP.
215. 7:43What is an IP? Okay? What is a network?
216. 7:45What is a host? What is a subnet? What
217. 7:48is a subnet mask? What is a CID range?
218. 7:50What is a default gateway? What is a
219. 7:51MAC address? Okay? Then we'll see what
220. 7:53is Address Resolution Protocol? It's a
221. 7:55very important protocol. Then we'll see
222. 7:57what is a TCP-IP model? Without
223. 7:58understanding the TCP-IP model? You
224. 8:00can't understand networking, right?
225. 8:01We'll see the difference between MAC
226. 8:03and IP. Why we have two different
227. 8:05address schemes and what the need is
228. 8:07for one over the other. Right? Then
229. 8:08we'll see how routing works in depth.
230. 8:10Meaning, whenever we need to send a
231. 8:13packet from any device to any other
232. 8:15device, we'll see in detail how it
233. 8:18travels over the network over the wire.
234. 8:21We'll see it step by step in this video
235. 8:23. Once we're done with our fundamentals
236. 8:25, once we're done with IP and MAC
237. 8:26addresses, we'll see our first
238. 8:28higher-level protocol, which is ICMP (
239. 8:30Internet Control Messaging Protocol),
240. 8:32one of the most important and critical
241. 8:34protocols in networking. Once you
242. 8:35understand this, then you'll understand
243. 8:37what ping traceroute is. You'll also
244. 8:39get an idea of which network utilities
245. 8:41you use that use ICMP under the hood.
246. 8:44Then we'll see what is ping? What is
247. 8:46traceroute? What are their use cases?
248. 8:48And we'll also see how they work under
249. 8:50the hood. We'll take a deeper look at
250. 8:53how ping uses ICMP and how traceroute
251. 8:56uses ICMP to function. Okay? Once we're
252. 8:58done with our networking fundamentals,
253. 9:00we'll jump into our transport layer.
254. 9:02First, we'll see what is UDP. We'll
255. 9:04take a complete overview of UDP. We'll
256. 9:06look at its use cases. What is it? What
257. 9:08are the different features of UDP?
258. 9:10We'll look at that. Then we'll see the
259. 9:12complete anatomy of a UDP datagram.
260. 9:14Okay? So, a UDP datagram, which is a
261. 9:16data unit of the User Datagram Protocol
262. 9:18, is UDP. We'll look at its entire
263. 9:20structure: headers. What are the
264. 9:22headers? How do they function? What is
265. 9:24the significance of each field? We'll
266. 9:26cover that in detail in a video. Then
267. 9:28the most interesting part of this whole
268. 9:30playlist is that we will Wireshark the
269. 9:32UDP traffic. Whatever we have learned
270. 9:34about UDP, we will do it practically.
271. 9:36That means in Wireshark we will catch
272. 9:38UDP traffic from the real world. And in
273. 9:40the caught response, we will validate
274. 9:42all the UDP headers that we have
275. 9:44learned and all the knowledge we have
276. 9:45gathered about UDP. Okay? So that is
277. 9:47also part of this playlist. Once we are
278. 9:49done with UDP, we will move into TCP,
279. 9:51one of the most, if not the most,
280. 9:53protocols of the Internet. It is kind
281. 9:55of a backbone of the Internet. So again
282. 9:57, we will do a complete overview of TCP
283. 9:59: what are the use cases? What are the
284. 10:00features? Why is it reliable? Why is it
285. 10:02controlled? Okay? Then we will see what
286. 10:04is TCP three-way handshake? TCP
287. 10:06connection termination. We'll look in
288. 10:08detail at how TCP's sequence numbers
289. 10:10and acknowledgment numbers work, how
290. 10:12they're calculated, and there'll be a
291. 10:14detailed video about that as well. Then
292. 10:17, similarly to how we looked at the
293. 10:19anatomy of a UDP datagram, we'll again
294. 10:20demystify the anatomy of a TCP segment.
295. 10:23A TCP segment is a data unit of TCP.
296. 10:25What headers does it contain? What is
297. 10:26the significance of each header? We'll
298. 10:28learn about that in detail. Then, we'll
299. 10:30also see what MTU (Maximum Transmission
300. 10:33Unit) means, what is PMTU (Maximum
301. 10:35Segment Size)? We'll also learn in
302. 10:37detail about IP fragmentation. Then,
303. 10:39we'll jump into the most important
304. 10:41concept of TCP: TCP flow control, where
305. 10:43we'll talk about window size (window
306. 10:46scale) and see in detail how TCP
307. 10:48performs flow control. Then we'll jump
308. 10:50into another concept of TCP: congestion
309. 10:52control. What exactly is congestion
310. 10:54control? What is the difference between
311. 10:56flow control and congestion control?
312. 10:57Many people are confused about this.
313. 10:59Then we'll see two or three algorithms
314. 11:01of TCP congestion control: TCP Slow
315. 11:03Start and TCP Congestion Avoidance. And
316. 11:05obviously, we'll see what ECN is. I
317. 11:07didn't include that point here, but
318. 11:09we'll definitely see what ECN is:
319. 11:11Explicit Congestion Notification.
320. 11:13Although it's part of IP, but obviously
321. 11:15, TCP also plays a role in ECN. Okay?
322. 11:17We'll read about that too. It's not an
323. 11:19algorithm, but it is a mechanism to
324. 11:21detect congestion. Right? Then we'll do
325. 11:23another practical one. This is the
326. 11:24interesting part. We'll inspect TCP
327. 11:26traffic using Wireshark in detail.
328. 11:29Whatever we read above, we'll validate
329. 11:32it all by catching the TCP traffic with
330. 11:35Wireshark. Okay? Once we're done with
331. 11:37the transport layer protocols, that's
332. 11:39TCP and UDP. Obviously, there's also
333. 11:40QUIC, but QUIC is built on top of UDP.
334. 11:42Maybe in the future, I'll add videos on
335. 11:44QUIC to this playlist, but I don't want
336. 11:47you to get confused. I'm going to cover
337. 11:49the core concepts first in this entire
338. 11:50playlist. Okay? Once we're done with
339. 11:53the transport layer, we'll jump into
340. 11:54the application layer, which is where
341. 11:56software engineers work. Okay? Then
342. 11:58we'll see another critical protocol of
343. 12:00the Internet: DNS, the Domain Name
344. 12:02System. We'll get a complete overview.
345. 12:03How does DNS work? We'll look at it in
346. 12:06detail. What flows happen? How are DNS
347. 12:08queries fulfilled recursively? We'll
348. 12:10also study that in detail. Then we'll
349. 12:12see each and every commonly used DNS
350. 12:14record. And we won't just look at it
351. 12:15theoretically. We'll see some scenarios
352. 12:17where they have a use case, like in
353. 12:19mailing. How do you detect spam emails?
354. 12:22How is email security achieved based on
355. 12:24these records? Right? So, we'll cover
356. 12:27all these things in the DNS records
357. 12:28video. Then again, we'll Wireshark the
358. 12:31DNS and we'll actually also see how DNS
359. 12:34works over TCP. Yes, DNS over TCP.
360. 12:37We'll catch inside Wireshark and we'll
361. 12:39see how that works. Okay? Then we'll
362. 12:41jump into HTTP, another application
363. 12:43layer protocol. We'll see what an HTTP
364. 12:45is. What is the structure of an HTTP
365. 12:47request and a response? Okay? We'll see
366. 12:49different versions of HTTP from HTTPS
367. 12:521.1 to HTTPS 3, then we'll see what Web
368. 12:54Sockets is, then we'll see what TLS is.
369. 12:58And then we'll end this playlist with
370. 13:00DSCP and NAT. You might say that DSCP
371. 13:03and NAT are kind of networking concepts
372. 13:04that should technically be in your
373. 13:06fundamentals. But I thought I was
374. 13:08making this for software engineers. I
375. 13:10wanted to first cover the major
376. 13:12concepts of networking before jumping
377. 13:14into these core networking concepts.
378. 13:17Because DSCP and NAT are generally more
379. 13:19closely related to networking than
380. 13:21software. Right? So, to understand DSCP
381. 13:23and NAT, if you know all these things,
382. 13:26it's easy for you to understand DSCP
383. 13:28and NAT. That's why I put it at the end
384. 13:30. But maybe I'll also add this to
385. 13:32Networking Fundamentals, because
386. 13:34obviously this is the first video and
387. 13:36obviously networking is a huge topic.
388. 13:38So, this isn't the end of this playlist
389. 13:40. In the future, I'll keep making more
390. 13:42videos related to networking and adding
391. 13:45them to this playlist. But if you
392. 13:47understand all these concepts, you'll
393. 13:49have your fundamentals clear. You know
394. 13:51networking, and you can debug network
395. 13:53problems as a software engineer.
396. 13:55Obviously, networking is much more vast
397. 13:57. If you're taking the CCNA exam or
398. 13:59want to do network engineering, this
399. 14:01can obviously be a good starting point.
400. 14:03And you'll gain a lot of knowledge from
401. 14:05it. And based on that knowledge, you
402. 14:06can learn more and prepare for network
403. 14:08engineering. Right? So, this is the
404. 14:11plan. I'll definitely be posting videos
405. 14:13every day about these topics. And this
406. 14:15playlist definitely has no end. As I
407. 14:17make more videos, I'll keep adding them
408. 14:19to this playlist. Okay? So, I'm really
409. 14:21excited for this playlist. I hope you
410. 14:24gain some knowledge once you watch this
411. 14:25playlist. If you have any suggestions
412. 14:27or doubts, please leave them in the
413. 14:29comments. I'll definitely clear them up
414. 14:30. I hope to see you in the next video.