The Tale of Two Kingdoms - OSI analogy

The Tale of Two Kingdoms

The Tale of Two KingdomsHow OSI layers workTales of Two KingdomWould it be nice if some one asked you how does network works? and you can tell ohh it works like this?

So to help you with that lets talk about a short story that is depicted that describes the logical things happen on a network.

So if we Understand this story, We can virtually apply everything from it oh how networks operate.

King A

So whats the king do for a leaving?He does everything it want. He got responsibilities but hes the king! Hes on the top of the kingdom.

And so King A wanted to invite or send an invitation to King B. (on the other side of the kingdom)

So si king A, ay nman tatayo sa throne nya tpos lalabas ng kingdom then tatakbo papunta sa kabilang kingdom para imbitahin ung hari sa kabila. Eh tama ba oh hindi?

So dahil sya ay hari at lahat ay nagttrabaho sa kanya, so ano ang gagawin nya?

So hat he will do? Tatawagin nya ung SCRIBES nya.

King A everybody works for him.

Scribes

So anu ung scribes, or sino ung scribes.

A person who copies/writes out documents, esp. one employed to do this before printing was invented.

So verbally, sasabihin ng hari sa scribe nya na scribe! Write this down!. So isusulat ni scribe ung request ni King A.

Dear King B, I would like to have lunch. Signed, King A

Tpos ung scribes na yun will add something, like alam nyu ung tinatawag na just my 2cents idiomatic expression. So its like putting something useful on something.

So ung 2 cents na un ay ibig sabihin eh nag dadagdag sya ng extra bit of information.

For example, maybe there is a period, or a Capital letter, or a parenthesis and so on, basta ung scribe is adding a little bit of over head on that message.


Scribe: Writes the message, ProvidesA service and add its 2 cents.

Scribes

So anu na ang susunod?

So ung scribe na yan ay nasa taas parin yan ng tinatawag nating hierarchy.

So ang question, lalabas ba sya ng kingdom, tatakabo or sasakay ng kabayo papunta sa kingdom ni king B para ibigay ung sulat?

Hindi diba? Since nasa itaas parin sya ng hierarchy, may nag ttrabaho para sa kanya.

At un ung Translator.



Translator

-so ung translator does a few things for a leaving.

-he gets the message everything the scribes put on paper.

-he takes it and he make sure na everything is presentable appropriately sa kabilang kingdom.

-so sabihin nating sa kingdom A, they speak certain dialog like Tagalog, at sa kingdom B eh medyo iba ung salita nila. Jejemon pala mga tao dun.

-so ung translator, eh babaguhin niya ung message in a format presentable sa kabilang kingdom.

-so bukod sa pagpoformat ng message, he also encrypt it.

-bakit? Bakit kailangan ng translator na iincrypt ung message?

-so anu nga uli ung encryption?



Translator: Correctly format the message,And may encrypt too.

Translator

-so ung encrypting, is taking the data that the king is sending and then we scramble it up so that if anybody is looking like an average person cant make sense of what it is.

-so pag nadeliver natin ung encrypted message on the other kingdom, ung translator sa kabila eh titingnan ung encrypted data and will de-encrypt it. So iiuunscrumble nya ung message para makuha ni king B ung message.

-nag dadagdag din sya ng 2cents nya, so minsan pinaiikli nya ung message or kinocompress nya ung message.

So ang translator ay nag chachange ng format ng message at nag eencrypt din iyun ung trabaho nya.

Then he will hand it down on the next logical person in the kingdom.




Lawyer

-yes lawyer xD bkit sya nasali?

-well maybe, we are not in good speaking terms from a kingdoms perspective on the other kingdom.

-so the lawyer, will negotiate for a conversation.

-una he will check if is it ok to happen? If so yes great!... Ill go head and let the conversation happen with kingdom A and King B.

He will also track it. Maybe gagawa sya ng paper work for the message to be sent out.

-so let us say, paper work 5249 is going to king B etc.

-so he basically he will sets up the deal, allow this conversation to happen, and keep tracking it.

-iyon ang trabaho ng laywer. He set ups the deal.




Lawyer: Negotiates the conversationBetween this king and others. Sets up theDeal.5249 => King B

So stop muna natin ung storya

Lets focus muna d2

So anything from kingdom A are what you call senior management team for king A.

Sila ung mga taong gumagawa ng policy, they decide whats going to happen but the actual heavy works will begin on the middle manager which is ung susunod sa storya, all the way down.

So the lawyer, after nya mag agree sa mga kasunduan ng mga kingdom, will add his 2cents as well.

So it might be the tracking number on the documents and so fort.

Then he will hand it down to the middle manager.King A everybody works for him.



Lawyer: Negotiates the conversationBetween this king and others. Sets up theDeal.5249 => King B

Middle Manager

Etong middle managers job is to make sure that ung massage ng king will be delivered.

So meron syang mga options para madeliver ung message.

He can choose to use reliable or unreliable delivery. So ano ibigsabihin ng reliable and unreliable sa kingdom.

So sabihin nating pag nag send ng mail, if we send a letter so it got the To and From, I can say registered mail, and if we send this registered mail, when delivered eh makakareceive tayo ng confirmation or awknowledgement saying hey! This message is delivered .

Mas mahal ba to? Yes! So sa kingdom A pag nag send tayo ng reliable it will cost more like some overhead, because we will gonna track it by adding some tracking number. Let us say Track 1026. then he will say thank you very much.

so iyun ung reliable means all about, its about sending sequence number, tracking numbers and getting awk back.King A everybody works for him.



Lawyer: Negotiates the conversationBetween this king and others. Sets up theDeal.Middle Manager: Uses reliable and unreliableMethod for sending the message, (Based onStandard).5249 => King B

Track 1026

Middle Manager So how about unreliable?

Unreliable ay ung sasabihin ng middle manager, sure! Ill send it out but im not gonna as for a receipt.

Its like sending a post card, so kung makakarating to sa pupuntahan, great! If it doesnt get there, I dont care.

Wala kayong matatangap ng awk back sa padadalan mo qng natangap ba or nadeliver ung post card and you just wish for the best.

So thats unreliable is all about.

So ung middle manager will use this reliable or unreliable transport requirements and hes not gonna do it from its own mind but he will base it on standards.

So if the message cames from the king. He should always use reliable transport. so kung galling sa ibang tao, maybe he might use unreliable para makatipid.King A everybody works for him.




Track 1026

Middle Manager -so sa pag baba ng message galling sa king, e2 daw ay pahaba ng pahaba, maybe dahil sa mga overhead na nilagay ng mga nauna.

-so ung middle managers will chunk it up or cut it up.

So the message (draw a message box). So this message is not just the kings message as you remember since some of the top managers added information like the scribes adding something on the message, the translator added information, the lawyer added some information and the middle manager adds the tracking.

So maybe the middle manager cut the message it two or three pieces.

So ung middle manager will say this is 1 of 3, 2 of 3 and 3 of 3. and also adds some tracking number on each one so the 1st one is 1026 and so on.King A everybody works for him.




Track 1026

Middle Manager So we are taking this message and we are segmenting it into smaller chunks if needed.

If that happens ang middle manager ang bahala jan.King A everybody works for him.




Track 1026

Middle Manager So we are taking this message and we are segmenting it into smaller chunks if needed.

If that happens ang middle manager ang bahala jan.

So kung titingan natin, etong si middle maneger eh hindi parin sya ung sasakay sa kabayo para ideliver ung message sa kabilang kingdom.

- dahil merun pa daw mga tao ang nag ttrabaho sa kanya. So ang susunod sa kanya is ung mail room.King A everybody works for him.




Track 1026

Mail Room

So ano ung mail room?

So ung tao sa mail room, will add some labels to the messages.

And bakit ko sinabing messages? Well kung ung initial message wich is king B lets have lunch and the middle manager chunked it to 1 2 3 parts, each of those parts, needs an adress.

So what do we mean by address, so lets think for a second kung san tayo nakatira. So let us say sa bahay nyu eh may address.

At ung address na yun ay may two parts we got the street name and house number. In addition yo might have an apartment number.

So sa mga kingdom, merun din silang address which is ung destination address is ung address ni king B and the source address is ung address ni king A.

So To: King B, who leaves on this street with the castle number like this. And From: King A, who leaves on this street with the castle number like this.King A everybody works for him.



Lawyer: Negotiates the conversationBetween this king and others. Sets up theDeal.Middle Manager: Uses reliable and unreliableMethod for sending the message, (Based onStandard).Mail Room: adds a label with the street andHouse numbers (logical addresses).5249 => King B

Track 1026

Envelope Stuffer

Hindi pa nag tatapos jan ang sa trabaho ng mga nasa mailroom, so after nya malagyan ng mga address ung message. Ilalagay nya ito ngaun sa sobre at ipapasa sa envelope stuffer.

So ano ang ginagawa ng envelope stuffer? So ang envelope stuffer ay kukunin ung message then stick it in an envelope.

So example is we got the 3 segmented pieces of message that we have received from the middle manager, to the mail room and now in the envelope stuffer. Those will be put into 3 separate envelope, and the other challenge we have is this thing ().

So sa ibang lugar, ung mga mail man eh hindi dinidiliver ung mga sulat directly sa mga bahay.

So you have a house, you got street address and house number but ung mailman eh hindi ito ededeliver directly sa bahay.

So sa mga ganung lugar eh sa mga street, may makikita kayong box that look like this. And on that box, theres a slot like 1 2 3 and so fort. King A everybody works for him.



Lawyer: Negotiates the conversationBetween this king and others. Sets up theDeal.Middle Manager: Uses reliable and unreliableMethod for sending the message, (Based onStandard).Mail Room: adds a label with the street andHouse numbers (logical addresses).5249 => King B

Track 1026

Envelope Stuffer

So example sa bahay na to sya ung number 1 or sa bahay na yon sakanya ung number 2. then the mailman will put the mail on the correct slot then the one who leave on those place check the mail regularly.

so jan sa mail stuffer lalagyan ngaun ng tinagawag na physical address or what you call the mailbox number.

So ano ung, iung ung information sa kung saan exksakto ididiliver ung sulat.

Then finally we can deliver them.




Lawyer: Negotiates the conversationBetween this king and others. Sets up theDeal.Middle Manager: Uses reliable and unreliableMethod for sending the message, (Based onStandard).Mail Room: adds a label with the street andHouse numbers (logical addresses).

Envelope stuffer: adds a label showingthe mailbox numbers (physical address) putsthe message in the right type of envelope5249 => King B

Track 1026

Delivery

So have the addresses, the logical and the physical then the delivery takes it over.

What ever delivery scenario we have like truck or car or horse as long as it can deliver the message to the other side.





Envelope stuffer: adds a label showingthe mailbox numbers (physical address) putsthe message in the right type of envelope.Pickup and Delivery: the actual message begins to meSent.5249 => King B

Track 1026

So the message got delivered

On the kingdom Bs place.

So the man on the truck and get down, will the man on the truck will hand it to king B? no, we have to go to the entire process again happens in reverse.

So dadalin sa mailbox ung envelope which is ung slot eh nakapoint out sa address ng castle ni kindom B.

- then they will check if para dun nga ung envelope na yun and if verified, they will remove the envelope and hand it in to the mail room.

So at king bs mail room will check if the message was addressed to them, then if checked, they will remove that information since its no longer relevant and will pass it out.

They pass it to middle manager, well he see that a message came in, if he saw that the message is sent reliably then he will send and awk back to kingdom A middle manager and saying thanks I got it.






Track 1026

Once the middle managerReceives that and sent anAwk, he now gonna remove any tracking number on it, and then send the raw message up on the stack up.

And who gets it, the lawyer, so the lawyer will say, are we in good speaking terms in king A, are we gonna allow to see this, and the answer is yes we are on good speaking term and we are specting that kind of message and receive it.

-now the lawyer will remove anything that the lawyer from king a puts in on the message.

Now he will send the raw message up.

So whats that raw massege, let us say its King B, lets have a luch, from king A. then it goes to the translator.

-so maybe the message is ecrypted so the translator on kingdom B will deencrypy it. He will remove all the formatting that has been done. Then he will pass that message to the scribe.






Track 1026

So the scribe will simplyTake the message and Read it to the king as a service to king B.

So after king b received the message, then if king b want to respond, the same thing will going to happen.

So whats with this story? This is a logical representation of what goes on in the mind of a network device like pc that sitting on a network, the toughts it got through when its getting ready to communicate in a network.






Track 1026

So the scribe will simplyTake the message and Read it to the king as a service to king B.

So after king b received the message, then if king b want to respond, the same thing will going to happen.

So whats with this story? This is a logical representation of what goes on in the mind of a network device like pc that sitting on a network, the toughts it got through when its getting ready to communicate in a network.






Track 1026

Documents

The Tale of Two Kingdoms - OSI analogy