Name: 什麼是 TCP/IP 和 OSI？// 免費 ccna // 第 3 集 (what is TCP/IP and OSI? // FREE CCNA // EP 3)
Uploaded: 2025-09-16T06:45:00.000Z
Duration: 12 min 4 s

This is episode three of my free CCNA course, and a huge shout out to Boson Software, the official sponsor of this CCNA course.

這是我的免費 CCNA 課程的第三集，在此向本 CCNA 課程的官方贊助商 Boson Software 致以誠摯的謝意。

程度副詞

They are the reason this can be made available for free, so I highly encourage you to go check them out.

正是因為有了他們，我們才能免費提供這些資訊，所以我強烈建議你們去看看。

They have the absolute best CCNA, CCNP labs and practice exams.

他們擁有絕對一流的 CCNA、CCNP 實驗室和模擬考試。

Okay, I need you to stop and think about this for a second.

好吧，我需要你停下來想一想。

I want you to appreciate the fact that this device right here, a Raspberry Pi, can connect to a network and talk to my iPhone.

我想讓你知道，這個設備，一個樹莓派（Raspberry Pi），可以連接到網絡並與我的 iPhone 通話。

They can share photos, they can email each other, do whatever.

他們可以分享照片，互相發送電子郵件，做任何事情。

It might not seem amazing because this kind of stuff is just commonplace, it's what we're used to every day.

這似乎並不令人驚訝，因為這種事情司空見慣，我們每天都習以為常。

But once upon a time, a long time ago in a galaxy far, far away, if you had a device that was made by two different companies, they could not talk.

但在很久很久以前，在一個遙遠的星系裡，如果你有一臺由兩家不同公司生產的設備，它們是不能通話的。

This is where things like the TCP IP model or the OSI model, networking models, save the day, like for real.

這就是 TCP IP 模型或 OSI 模型等網絡模型拯救世界的地方，就像真的一樣。

Well, let's take a look back in history real quick.

A long time ago, I'm talking stone ages, 1960s.

很久以前，我說的是石器時代，20 世紀 60 年代。

Some smart guys are sitting around with their computers and they were thinking, man, gee willikers, I really wish they could talk to each other.

一些聰明人圍坐在電腦前，他們在想，天哪，我真希望他們能互相交談。

I wish I could share a file with you, friend.

我真希望能和你分享一份文件，朋友。

They go, what if we can network these things together?

他們會想，如果我們能把這些東西聯網呢？

What if we can connect our computers together and we could send data across?

如果我們能將電腦連接在一起，並在彼此之間傳輸數據呢？

They did that. 1969, the birth of the first network.

他們做到了1969 年，第一個網絡誕生。

We called this, or they called this, ARPANET.

我們稱之為 ARPANET，或者他們稱之為 ARPANET。

DOD or the Department of Defense came up with it and it was revolutionary.

DOD 或國防部提出了這一概念，具有革命性意義。

Like people could actually have their computers talk to each other, which I know sounds like a, not a big deal right now, but back then that was, that was it.

就像人們真的可以讓他們的電腦互相對話一樣，我知道現在聽起來沒什麼大不了的，但在當時，就是這樣。

就像他們，他們合法地做到了。

Like here's the first like network diagram I think there ever was.

這是我認為有史以來第一張網絡圖。

And when I say idea, they were like, yeah, this is a cool thing we can do.

我說 "想法"，他們就會說，是啊，我們可以做這件很酷的事。

They actually invented what's called packet switching, which is what we do today.

實際上，他們發明了所謂的分組交換，也就是我們今天所做的。

But what they didn't have yet is the how, how do we make these computers talk to each other?

但是，他們還不知道如何讓這些計算機相互對話？

You see that part wasn't quite ironed out, but the idea, the idea spread like wildfire.

你看，這部分還沒有完全理順，但這個想法，這個想法像野火一樣蔓延開來。

So companies like IBM, they were like, heck yeah, we have computers.

是以，像 IBM 這樣的公司就想，是啊，我們有電腦。

It was proprietary, meaning it only worked with their stuff, which is fine if you have an IBM computer, but there wasn't just IBM.

它是專有的，這意味著它只能與他們的產品一起使用，如果你有一臺 IBM 電腦，那就沒問題，但並不只有 IBM。

There were other companies and guess what these other companies did.

還有其他公司，猜猜這些其他公司做了什麼。

When I say design, I mean, they like invented their own networks.

我說的設計，是指他們喜歡發明自己的網絡。

They came up with the idea of how to actually connect computers together.

他們提出瞭如何將計算機真正連接在一起的想法。

And because these networks were proprietary, they couldn't really play well with others.

而且，由於這些網絡是專有的，它們無法與其他網絡很好地合作。

Meaning these networks could not communicate.

Couldn't have this device talk with this device.

無法讓這臺設備與這臺設備通話。

They were basically speaking different languages.

他們說的基本上是不同的語言。

And this network over here was like, what?

現在，我想把這一點敲定下來。

Like we're, we're so used to ethernet cables.

就像我們一樣，我們已經習慣了以太網電纜。

Each of these companies had different versions of whatever they called theirs.

每家公司都有不同版本的名稱。

Like you ever try to charge your iPhone with an Android charging cable?

你試過用安卓充電線為 iPhone 充電嗎？

That was the networks of yesteryear or long time ago.

這就是昔日或很久以前的網絡。

Now, eventually they realized, Hey, this is kind of stupid.

現在，他們最終意識到，嘿，這有點傻。

Maybe we should all use the same networking stuff.

也許我們都應該使用同樣的網絡設備。

This involved meetings and committees and I want to do this.

這涉及到會議和委員會，我想這樣做。

Now there's a long and maybe interesting history.

If you're into that, of how this all came about, but we eventually ended up with a networking model, a model that defines how we can connect our stuff.

如果你想知道這一切是如何產生的，但我們最終建立了一個網絡模型，這個模型定義了我們如何連接我們的東西。

So that when IBM makes a computer, when Apple makes a computer, when Microsoft makes a computer, we're all putting the same technology inside that computer to make it talk to the other computers.

這樣，當 IBM 製造一臺電腦、蘋果公司製造一臺電腦、微軟公司製造一臺電腦時，我們都會在這臺電腦中採用相同的技術，使它能與其他電腦對話。

That's why such a beautiful thing that a Microsoft computer can send a photo to an Apple computer.

這就是為什麼微軟電腦能將照片發送到蘋果電腦上的原因。

We're all using the same networking technology.

我們都在使用相同的網絡技術。

We're using the same networking standards.

Now, actually, honestly, we ended up with two models, one that we actually use.

實際上，老實說，我們最終有了兩個模型，一個是我們實際使用的。

And then one that we still cling onto and talk about all the time.

還有一個，我們至今仍念念不忘，時常掛在嘴邊。

I'll show you the model we use today is called TCP IP.

我將向你展示我們今天使用的模型，它被稱為 TCP IP。

This is what every computer supports and implemented into their system, the TCP IP model.

這就是每臺計算機都支持並在其系統中實施的 TCP IP 模式。

Now the other model, he wanted to be the one that won so badly.

現在，另一個模型，他非常想成為獲勝的那個。

They were campaigning, but he just did not win TCP IP one for a variety of reasons, but it was just more widely adopted.

他們都在競選，但由於種種原因，他沒有贏得 TCP IP 一役，但它被更廣泛地採用了。

So then why am I still talking about him of TCP IP one?

那我為什麼還在談論 TCP IP 的他？

Now, again, TCP IP is a, just a list of rules or guidelines standards on how computers can communicate, how we design those systems.

再說一遍，TCP IP 只是一份關於計算機如何通信、我們如何設計這些系統的規則或指導標準清單。

So to make things more simple, more digestible, easier to understand and implement.

是以，要讓事情更簡單、更易消化、更容易理解和實施。

We divided all those functions into layers, layers like this right here, each of these layers to find some kind of protocol or standard we'll use when computers connect.

我們將所有這些功能劃分為若干層，就像這裡的這一層，每一層都要找到計算機連接時要使用的某種協議或標準。

So for example, the physical layer, we know that's going to involve ethernet cables, the network layer, all about IP addresses and routers.

例如，物理層，我們知道這將涉及以太網電纜，網絡層，所有關於 IP 地址和路由器的內容。

是以，對於這一標準，我們都表示同意。

We're going to use IP addresses when we communicate over the internet before that standard, that wasn't really the rule.

在該標準之前，我們在互聯網上通信時要使用 IP 地址，但這並不是真正的規則。

You could have done TCP UDP port numbers.

And then application like, Hey, when I open up my web browser and I go to netflix.com, what protocol am I going to use?

然後，當我打開瀏覽器訪問 netflix.com 時，我要使用什麼協議？

Do we all agree to use the same protocol?

我們都同意使用相同的協議嗎？