TCP/IP Protocol Explained in the simply way | Become NetWork Administration | tcp Configuration |

the devices and the connectors supposed to be manufactured by the same manufacturer for example let's say that you have iPhone okay then you need a SIM card right you need a charger right then you are buying something called as what uh airpods then you are buying a smartwatch right do we have any condition that all of these components has to be from Apple of course iPhone you can buy from Apple charger do I have to buy directly from Apple or I can go for a compatible device different device different places it it can be apple or it can be someone also some other devices also the same logic is also there apple is producing or manufacturing the SIM cards no there are different service providers right the man the service providers will be buying the SIM card from the manufacturer and they will associate them similarly airpods can be from any manufacturer Smartwatch can be from any manufacturer if there is a condition stating what if you're if you're using iPhone all the components you have to use only from Apple then what will happen we know Apple products are little costly or costly or costlier costliest anyway however you want you can mention it but the point is I'm quite happy with the product right but I'm not happy with the charger why should I pay that much because there is a compatible device which which which which cost me half the price of your uh Apple charger right so why should I buy that if at all this has to happen the user has their own preferences they can decide what they want how they want if Apple would like to enforce that only the app Apple components can communicate with each other they could develop some proprietary protocols for the communication maybe between the airpods and iPhone maybe from SmartWatch to the iPhone Smartwatch between between the Smartwatch and airpod they may be using a proprietary protocol because of that what will happen only the Apple products they can communicate with each other even though you are interested in buying a different vendor product you couldn't do that why because whatever the technology or whatever the protocol whatever the cable they are using they're all proprietary but the industry don't want that right they wanted to have um uh like what any product that can interoperable right with any of the other devices say I can buy a charger from uh let's say Google I can use it on iPhone I'm just telling you right nowadays you have a type-c connector on you earlier we used to have phone yeah a new phone comes with unival so we don't have any problem as long as the power requirements are met it doesn't matter which company product you are buying if this has to happen there must be a standard way of defining the rules like what power this is how it has to be transported adapter this is how it has to be manufactured cable this is the standard they have to follow if there is no standard defined every manufacturer they may have their own standards everyone may claim that this is the best standard so that's where the standards body came into picture like what we have a standard body called as I who I Institute of electrical and electronics Engineers it's a forum all right so they are responsible for developing many of the things and they requested ISO to develop a standard for we know what is ISO right yeah uh probably you may be hearing that International standard standard organization organization yes okay International standards organization right what do they do they develop the standard for the whole world if this is your requirement this is what the standard you have to follow any manufacturer who wants to get into that business they just need to read and understand the standard accordingly they will manufacture the product what is the benefit for the consumer doesn't matter who is the manufacturer which brand of product you're buying they can interoperate or they can interoperable they are interoperable correct now yes right so that is how we got something called as what OSI layers now what stands for OSI layer open system interconnection this is what Osa layer stands for okay then why they calling it as layer layer OSI is enough right then why we are calling it as layers let me tell you something assume that um Mohammad is starting up a company let's say halim is starting up a company and this business requires so much of functions for example everyday uh Bank transaction they have to go to the bank they may do something they may need to go to the warehouse right they may need to take care of the finance part of it accounting they have to do it they need to meet the customer they also need to go for the support there are many activities are there that business can we say that only Muhammad is going to be doing all the activities he could he could but how the performance will be and what kind of the delay is being expected because he may be expected to have his presence in every activity how that could be possible maybe he may need to approach a scientist who can make a clone of him am I right so he needs to so Muhammad halim needs to hire gaji and Socrates to help his business exactly right correct correct what I'm trying to say here is recruit the people who has the expertise on those department so Finance give it to people who has that experience technical hire the people who have that part of experience who are interested in to do that sales that is an entirely different ball game right so every department requires some specific skill set you canot expect one to have all the skill sets corre similarly if a program is being developed let's assume that a program is being being developed if the programs are being developed from the scratch as a single module what I mean to say single program if any changes needs to be done the changes can be done at the same time you have to do compile the whole program even though you did a small change probably tomorrow you would like to introduce a new feature or new function that function is going to be appended as part of the main program code and you need to recompile everything even a small mistake in the code is going to be causing the trouble for the entire application so what we are trying to do is instead of doing the whole application as a single application let me create that as individual modules right so individual mod for example if I click uh the file is that visible insert menu if I click that insert menu if I click the draw is that visible for you guys design layout references is that visible for you all the menu what I'm clicking here right so what I'm trying to say this Microsoft Word application has been divided into small small modules the home functionalities everything what you have in home is given to one team insert functionalities have been given to another team it's not that a single team it can be multiple teams also the purpose of doing this what happens anything needs to be done in home only that part needs to be modified and uh the compilation is going to happen only part that particular part the rest of the new functionalities whatever you come up with develop those functionalities and then add them together add it to the existing functionality one minute please uh give me minut guys I'm getting a call let me check it out hello Raj halim B yes practice okay okay last hello I'm sorry guys sorry guys I got a call that's why oh okay that's fine right uh you were in the middle of something or you ask you were asking something no no nothing just no we're just chatting a little bit that's okay okay fine so what I'm trying to say here is each and every menu I can consider it as a separate module I can depute a team who is responsible for that even tomorrow if a new module needs to be developed or new function needs to be added to an existing module it is going to be easy to identify that that's the idea for going for individual modules similarly the whole functionality of data transmission right from ma PCA to PCB when you're trying to exchange the data what happens is the whole process has been sliced into small small activities we call it as layers you're getting my point okay I got it yeah right yes so layers like your departments right compare that one with your department in company you have some departments so every department is responsible for doing something right without the coordination of each and every Department do you think the business can be successfully executed obviously no right similarly every layer is responsible for doing some activity depending on the applications presence in which of the layer those functionalities are going to be added to it right okay now so how many layers are there totally seven layers are there immediately people may be asking why not eight layers why not 10 layers Why seven layers there is no answer for that because they felt that the the existing working functionality require only seven level of slicing if seven departments are there which is more than enough for the network communication that's how they did it then how they derived seven layers because they had a reference earlier which is called as TCP IP model okay they already had a model using which the communication was happening but there was a problem in the interoperability so what they recommended is okay there is a model if you would like to use it you can use it if you would like to modify it if you you can modify it or you just wanted to use that as a reference you're coming you would like to come up with your own design you can do it but what they did is they identified the functionalities of each and every layer within dcpip and they felt that some of the layers can be further sliced for example in TCP IPO model we had three layers sorry four layers application internet or they call it as uh host to host uh network access this is how they used to be splicing this one now what they did is right this application further sliced into three layers in osla let me say this one as what uh application person ation then session so what they felt is the application layer of tcpip model when Osa got developed ISO felt that application layers activity is huge we don't want to keep as such instead let us slice that application layer into three layers that is how we got application presentation and session okay then we had host to host that host to host layer has been mapped to a layer called as what transport okay then they had something called as Internet that internet layer has been mapped to something called uh Network layer this network access layer right this network access layer further sides into two layers one is called as uh data link layer and phal dat right you're getting my point right so give me a minute I will try to find find the picture so that it'll be easy easy for you now I'm just pasting an image here so that it'll be easy for you can you see that yes so application layer has been mapped to application presentation session host to host is mapped to transport layer internet is mapped to network network access layer is mapped to data link layer and physical layer okay now what is uh um gy what is DoD model uh that's what I'm about to say you might be wondering there is something called as DOD here right so do stands for Department of Defense this model initially used in us defense okay also can we have this notes shared to us please every class I'm sharing the notes Socrates am I not yes I got it yes every class I'm sharing it if I missed anything please let me know okay all right okay now that we know what is o a layer right and also we know why layer correct now all right now further now let's try to understand what is the responsibility of each and every layer now after this one if you could watch that video you will get more of understanding I believe so I know that is huge I know I'm not saying that it is simple it is easy but uh even if you're trying to get around 20 30 percentage out of it I would be happy when in the video when you are um giving the example right and you you were giving a lot of example like a real life scenario uh connecting with the OSI layers um and um those is that helping you yeah yeah but I was thinking how those are related because I did not really catch it uh properly okay yes can you please tell me one example of that what is that the problem you are facing one example give me one real life example which I said and that is confusing you or you not able to get to it um I barely remember it because I okay okay video like week on my on on every class I used to say to myud students okay don't think that simply I'm calling it a you are my students yes don't feel bad you are my student of course of course anytime we are in the learning process we are students okay yes in every class I used to tell one thing when you are reading the notes or whenever the videos I'm giving it to you watching it the moment you have some problem you need to clarify it don't hesitate to note it down if you don't note it down 100% you will forget out that is correct that is correct you can post the question immediately in the group also if you want if you feel that where do I keep it and all I normally say when people are coming physical classroom they keep they come up with a note right so on one side you go with the class notes backside start note your start noting your questions mhm so that when you're coming to the class it will be easy for you what what is that question I supposed to but I remember I remember that you giving a lot of examples is that correct go yes yes yes yes okay see the purpose of giving the example is even if you can't forget the terminologies or the concepts by remembering the examples you can you can recollect all of them that's the idea for it for someone like why more than one example is being given see the moment you we complete this OSL layer you really don't understand how the class is getting completed that fast the class will be over right so I'm just taking uh little bit of time on the fundamentals so that even uh later when you read a document you should be in a position to interpret the document what is that they're trying to say even see if you don't don't answer the question if you don't know the answer it is not a problem if you don't understand the question itself then it is a problem am right or not so now I remember one of the example since you ask yes please tell me that uh we are living in a house and then in the house that we have uh different rooms uh we have the bedrooms we have the uh living room we have the k um so uh the room is like a sorry the house is like we living like 1600 2,000 uh I believe that example is for subnetting okay not for because every room you won't be having a separate address for the house you will be having the address that address I'm calling it as a parent address or major Network every room you are slicing that parent Network into child networks that's what sub Network okay uh yeah that's that's the one that it came to I got it I got it I got it sorry yeah whatever it was that that the example it came to my mind fantastic now so let us try to understand the physical l so I as I said earlier every layer has its own responsibility correct now yes they are going to be doing some sort of activities now what is the role of a physical layer So Physical layer says if at all the communication has to happen the devices needs to be connected physically got it the connection may be wired or Wireless that doesn't matter Excuse me yes so the physical layers physical layers functionality is what the devices which are participating in the network they have to be connected physically it may be wired or it may be wirless it doesn't matter for me got it yeah right so depending on the type of connection right the depending on the type of connection the the the cables the connectors the devices what we use may be varying now here the cables what we use in current scenario is known as UTP cable or often we call it as copper cable copper C all right so in UTP is nothing but unshielded Twisted P we also have something called as STP STP is nothing but shielded Twisted per right the difference between these two is there is a shield within that insulation that Shield is going to be ensuring that the interferences are being avoided getting my point right can I use Shield everywhere you can but do I use it I don't why because the cost of shielded twisted pair is going to be little bit High whever it is really required I may be using it for example if you're going to be browsing a website do you need a username and password account no not every side no whenever you're doing some specific activity like what when we use like um the internet for the company's website they require the username and password not necessarily to browse through you not every if you're planning to do some specific activity for example the company is giving a service you are a consumer of the service then you may need to log in just to go through what are all the services are available what plans are there I don't need to have a a login got it is that clear yes yeah so wherever The Shield is required I'm saying I'm saying that um like I work the educational institute the public Educational Institute when um publ were trying to get into the website I'm not sorry public uh the Personnel the staff members were trying to get into the interet like their um own website to see the benefits or all other stuff they needed to log in to that system that's what I'm saying this this the group policy Group Policy is like a company provide a group you cannot go Facebook you cannot go Amazon the group policy all over the network the same thing Group Policy not it is not necessarily has to be group policy there are so many types of implementations we can do in that right but not necessarily for every access that you're trying to do okay yeah okay so wherever The Shield is required you can go for it similarly in general we don't want to Shield it so the unshielded twisted pair wires can be exposed for some sort of interferences quite possible okay go can you can you um scroll down a little bit I cannot see it okay now no scroll up sorry the bottom yeah yes yes now I can see okay so you cable what the difference the you cable and in STP you will have a shield extra shield will be there see I'll show you one okay give me a minute let me share the whole screen so that it'll be easy for you I just shared only the word okay can you share a image shielded uh unshielded how that's what I'm doing Ma that's what I'm doing just wait okay I don't know why it is not coming ah it say come okay now Shield Ted par see here can you see the shield here there is a shield they have a four pair yeah I got it so if you don't have the shield then it is called as unshielded Twisted P oh okay this The Shield right okay yes this is The Shield yeah now this Shield will ensure that no external signal can be given inside so that it can cause some interferences on the signal traveling through these cables only where it is required you can go for it but if you have a budget and you have a real reason for that nobody is stopping you and buying the shield shielded Twisted per for example let me say that in in for example uh unshielded twisted pair if the one meter cost is let me say $1 example only don't take the literal meaning of it okay unshielded twisted pair cable meter one uh $1 means Shield a twisted PA somewhere around $3 to4 maybe they so the shield shielded is more protected than the unshielded correct at the same time shielded is costlier than unshielded that also we need to understand okay got it okay now here in unshielded twisted pair you will not have that one can you see them uh yes right [Music] mhm this one you don't have that Shield can you see that yes okay see this is UTP and this is STP they given the one thing see this is also a type of Shield don't say that this is how you will be having the shield in every type of cable m The Shield may be like this or the shield may be for every wire also oh the are more expensive exactly yeah right so it's up to you how do you want to go for it if you have a budget and you have the real reason for using that can you can you show me one more time the UTP and the STP please can you see them yes okay so UTP has uh no shielded sdp has shielded correct correct okay got it can you see that the shield there is no Shield here yes okay so the type of Shield could be any any type okay now now how the data is going to be transported on the wire in the form of electrical signals right how the data is going to be transported on the cable in the form of electrical signals but my point is how far the signal can travel now we are connected and we are in different different places correct whatever I'm speaking that is going to be converted into a data that data is going to be traveling through the cable maybe in the form of electrical signal or depending on the other type of cable it may be using different technique now for the discussion we took only what UTP cable the copper cable where data will be transmitted in the form of electrical signals but do you think that the signal can travel all the way from India to us no then how come we are able to communicate that's not possible then we should uh wiress we should use wireless so the whole world we can go with wireless then how come the wireless signal can travel from here to us how much time it will take and do you think that the signal can travel that far okay now you have a a cable connection at your home do you have a cable connection at your home for watching TV right now there will be a service provider who is responsible for providing the connection and who is also going to be responsible for serving you the cable which is being terminated to you is not a single cable from the service provider there'll be many places the cable will be traveling correct now you could also see in between a booster they will be keeping it a signal booster they will they'll be keeping it we call we they call that as a DB booster or DB box we could say that the Wi-Fi extender or something else maybe maybe don't get into the Wi-Fi now because we yet to discuss about the wireless okay okay this is electrical signal right any signal which is being sent May grade at one point whether there is an interference or not then how come the signal can travel farther you need to amplify the signal right like what see if you have a uh what is it called uh audio system in your home all right you're watching TV right what you can do if you're if you're not able to hear the audio properly you're increasing the volume right uh we use the external speaker anything whatever you want you can do it but basically the signal strength is going to be Amplified that's what we are trying to say right right initially to extend the signal from to a farther distance we were using a device called as amplifier but the problem with amplifier yes it amplifies the signal it also amplifies the noise what is noise unwanted signal is noise for me right so we would like to eliminate the noise but we want to imp improve or increase the signal Str that's where we came up with something called as what uh repeater right repeater repeater repeats only the signal nothing else whereas amplifies the signal and noise you getting my point is that clear yeah so amplifier is is a modify is the amplifies the signal and noises and repeater only signal only the signal so that the signal can travel farther okay so again if you would like to extend the signal strength you can put one more repeater over there right then we had some problem with the repeater what is that it had fewer ports we cannot connect multiple devices into it okay so we came up with another device called as a hub which is also known as multi-port repeater now we know what is the repeater correct when I say hub it's a multi-port repeater that means you have multiple ports embedded into the device so electrical signals are traveling on the cable right as the signal is traveling it it can get the signal strength may be weakened to increase the signal strength we need couple of devices the first device what we were looking at is amplifier amplifier amplifies the signal correct but it also amplifies the noise to overcome this we came up with repeater repeater repeats only the signal but it had fewer ports if you would like to connect more set of devices then it is expected to have multiple ports ports are nothing but interfaces okay so gopy is Amplified repeater is not comes together one device or is the multiple device sorry sorry is not comes together repeater and amplifier there's no repeater nowadays only hubs are there okay what what is a hub Hub is nothing but you have multiple interface into it okay here it's a fewer Port now here multiple port okay right are nothing but which one you want to see as a repeater amplifier and HS you don't see amplifiers and all now oh those products are absolute see this is Hub okay okay we we we have a hub in your company no you will not be having Hub oh you will have that you will have that device called a switch Yeah and now we're using switch yeah yeah now comes switch right okay now the hubs are hubs repeaters amplifiers cables any connector that you use they all fall under the physical layer it will ensure that the signal can be receivable for the receiver clear yes okay fine the second layer what you need to understand is the data link layer now the primary functionality of the data link layer is what I typically call this as conversion function what is that conversion function okay now um how many of you have opened a PC and seen inside what is there inside a processor motherboard PCI card yes um video card processor many cards will be there right now let me show you here sound sound card uh PC a minute one more guy is calling yes hello yes sorry yes yes hello sorry guys now if you see this inside if you take any of these cards PCA cards or the cables whatever we use inside you will be having a flat bus for example let me take a video card card for PC let's say can you see that here yes this is the circuit connects flatly to the motherboard yes this one can you see that yeah that means these many circuts are connecting to the motherboard using these circuits the communication can happen between this card and motherboard and motherboard and the card yes that means consider these are the lanes in the road that means parallely many bits can travel yes we call this kind of a communication as a parallel communication the parallel communication yes whereas the cable what we use the UTP cable or the fiber cable whatever it might be the communication is serial when it say serial one by one only can go here parallely multiple bits can be sent and received can you see them this bus yes whereas on the cable what we use they are serial yes so basically the data link layers primary function is what converting parallel to serial and serial to parallel between the devices on the center end parallel will be converted into serial on the receiver end serial is going to be converted back into par got it yes okay that is one the next thing is the data link layer has two Su layers into it there are two layers in data link layer which are sub layers of data link layer the top layer is known as LLC and the bottom layer is known as Mac right yes the data link layer has two sub layer right the top layer of data link layer is known as LLC bottom layer is known as Mac Mac stands for media Access Control you getting it yes LLC I'll explain you what is that don't worry logical link control right now basically these two sub layers are even put together as a data link layers one more responsibility is what link establishment maintenance and termination is also the responsibility of data link layer what I mean to say assume that your PC is connected to the network using a cable all right if you unplug the cable on the PC side side or if you unplug the cable on the other end immediately you can see the notification the network is disconnected correct yes how does the PC knows on the PC side if you remove it the PC May recognize it on the other side if you remove how the PC can identify that the network is disconnected that's where this data link layer functionality comes into picture okay there is a protocol sorry okay go ahead there is a protocol called as keep alive which does it but anyway the two sublayers has some specific functionalities right okay right the two sublates has some specific functionalities which is known as LLC and Mac Mac is a number provides a unique identity for the device connecting to the for example your employee code is a number right yes okay so which is 48 bits in length expressed in hexad decimal format right and the first 24bit is known as oui and the remaining 24 bits can be randomly generated what I mean to say if you are the manufacturer of any of the data link layer product you have to have the MAC address if you're planning to have the MAC address those must be unique right and if you're planning to have the Mac addresses first of all you need to register when you register they will give you the first 24 bits to you something like if you connect a card to the PC and you reboot it you can identify that real Tech network interface card Intel network interface card Cisco network interface card is ident is found would you like to install the driver for that do you see that notification see if it is going to be a card that can be identified but how come the operating system could recognize it is Cisco it is realtech it is Intel that's where these first 24 bits are helping them the oui stands for what organization unic identifier got it yeah yeah got it okay the remaining 24 bits can be generated by the manufacturer itself randomly okay those those those 24 remaining BS for what um see totally 48 a serial number kind of a thing I manufacture a card first 24 bits all of my cards has to have common correct okay the remaining I can give unique number for every card I manufacturer like let me say gopy is my o y then I can say 001 then for the second card I can see 002 for the third card I can see for all of them the first 24 bit is gopy only like this I can give the sequence numbers okay now got it right in Mac most of the people they call it as Mac address but that's not the terminology Mac is not an address it is a number right but the other names for the MAC address we used to call it as data link address physical address yes right then Hardware address so many names are there Layer Two address why Layer Two because the first layer is physical layer layer second layer is data link layer layer to address however you want you can say but all of them are supposed to be identified as numbers okay I'm just giving you some five minutes of break here I'll be back okay sure if you would like to discuss it you can have the discussion I'm just passing myself okay k hm what's the difference between Mac address and serial number you have a you have your um oh Mac Seri number every device has Mac address so why you need serial number serial number is the product product number is the product serial number MAC address is The Logical is a physical address is a network can read this number serial number cannot read mat different different serial number is the product address like you you produce like a 5,000 product they put the number okay so [Music] number number [Music] [Music] printer scanner right right right right n no oh okay [Music] informational number number MA address right address totally [Music] Sy number number number 4 letter [Music] combination colon one C colon something like that right right right right right a gen C right [Music] okay information computer okay number assag number [Music] c okay number service [Music] for dis service right yes parallel communication versus seral communication by 30 30 fhe PR [Music] NE FL [Music] for Lo okay now mathematical [Music] ter comb exale [Music] [Music] 48 4 4 24 [Music] number 4 apolog sorry guys no no that's okay uh what go uh from the discussion one question we arise uh about hexa decimal that uh we need to little clarify hexad decimal H what is it what needs to hexad decimal is a format see in decimal what all the numbers we have 0 to 9 correct yes 0 to 9 but uh we can go Infinity on that after 9 you will get 10 11 12 13 like that 20 21 22 23 you'll get it correct now yes so we call this as a decimal in binary zero or one yes okay in hexa you have 0 to 16 positions that 0 to 9 and then instead of 10 you will have a instead of 11 you will have B like that c d e and f these are all the POS possible values this is base 10 this is base two and this is base 16 okay okay all right so uh the the normally uh what is it called your Mac addresses are going to be referred in hexad decimal similarly uh uh we have another discussion later on we will having it that is IPv6 uh that also falls under heximal notation only so for the hexad decimal numbers we use it in a MAC address correct correct in Mac Mac addresses are represented in heximal and every device has a MAC address and when they assign the MAC address uh how do they assign that Mac address how do they create it how do they create in the sense like 48 bits are there right MH so 48 bit representation how do you do it one hexadecimal character will go to four bits of representation so almost 12 hexadecimal values you will have it well okay so don't go delve into this if you want we can discuss things offline but not in class then we will not be able to finish it in as as for our schedule yeah that's true okay okay oh all right now IPv6 also uses hexad decimal format only but now so I explained you only the Mac sublayer correct Mac provides unique identity of an endpoint which is connecting to the network okay when it comes to the L LC logical link control I'll tell you a couple of examples on this so that it'll be easy for you to remember how many of you have some loans car loan housing loan personal loan anything anybody has any loan yeah house lot of loan almost everyone will be having some loan okay assume that you have taken the loan from bank here correct yes to whom you have to repay can I repay to bank B no no okay why is that I have to repay borrow from B exactly okay now why I'm relating this see until this data link layer you cannot have more than one technology that could coexist what I mean to say if you're using fiber in physical layer the other side should also be fiber if you're using copper on one side other side should also be copper if you're using Wireless right so you understand that one you cannot have more than one technology one side ethernet one side fiber not possible right so on above this data link layer you have a layer called as what network layer right this this network Cay onwards you can have more than one protocols that could exist for example let me say system a has um IP there is another protocol called as ipx there is also another thing something called as mpls now PCB also has some other protocols like IP ipx MLS C LNS don't worry about if you don't know about this MLS clns and don't worry consider these are Bank a bank B Bank C now the sender is sending the traffic via IP the receiver needs to process the data using IP am I right yes how does the receiver knows on network layer the received traffic has to be handed over to IP or ipx right that is where the LLC comes into picture that's where the logical link control understands that using which of the higher layer protocol the traffic has been transmitted by the sender based on that I will hand over the traffic to the right protocol on the receiving station that's where the logical link control got it okay yes yes right so what I mean to say The Logical link control is responsible for the upper layer protocols binding and also this link establishment link maintenance link termination is also the responsibility of LLC okay that's the network lay sorry that's the data link layer I'm just going to wrap up the session with network layer because it'll be too much to take it okay layer three which is Network layer okay now let's assume that uh everyone you can think from your perspective you have your home and you also have your office assume that the mode of trans as you do go every day car or bike or public transportation any mode but my point is from your house to the office how many routes are there only one or more than one more than one more than one oh which one you prefer to use where is the L time less time less try Okay so some people may say that maybe distance may be higher I don't want to get into I don't want to use the road where the traffic congestion is more some people may think that I would like to use the shortest road so that I can save some fuel all right or somebody may say that I would like to use this route because I would have to pick up my friend quite possible Right everyone may have their own reasons for using a specific route so basically how this is going to be happening is through the help of logical addressing we already know one address what is that physical address me address exactly now we are talking about something called as a logical address I'll tell you what is this logical address now um do you have pin code over there in us for you for a location how do you identify them logically let me take they have a Gip code have code exactly that's what here we call it as pin code or zip code however you want you can call it as yes now what is that zip code is all about it's a number right yes when you have the complete address what is the need of zip code H because um say same address there are lot of houses so no no you have the address 1 a uh ABC Towers First Street uh second cross something like that yes right now for 1B you will have the flat number as 1B yes but still you prefer to use the ZIP code why okay now assume that um you are sending a parcel to your friend okay you're sending a parcel do you think that the Parcel Service has only one job which is carrying your parcel from your house to your friend's house yeah with a g code they could sort out easily exactly they will have so many Parcels they need to organize these packages according to the destination it has to be sent to correct yes for that they have to read the address fully if not it will be very difficult for them instead if I have a logical way of identifying each and every location the Distributors no need to worry about reading the full address instead they can simply go through the uh logical number and they can understand where it is going and accordingly they can also be sorting it got it that zip code is a logical address got it yeah yeah similarly here The Logical address is called as IP address yes okay yes now once the IP address of the destination is known we know whether the destination device is in my network or in remote Network I can get that the second thing is once I know the destination I may have multiple routs to reach the destination among which best path is going to be chosen the best path can be based on any parameter I'm not saying that shortest route is the best route longest route is the best route it can be anything but my point is one of the route is going to be chosen according to my requirement that route is the best route for me okay let's say like all of you are having a TV at home am I right or not yes what brand everyone is using Socrates um uh I am using Phillips is that the only best brand available no there is a Sony there a lot okay now you yourself is saying that you have other brand you bought Phillips but you're saying that there are other good brands also Sony Panasonic LG Samsung there are so many but something something triggered you to choose Phillips MH right maybe some specific requirements you may have MH same way best path can be different for me from you MH that best path determination how I'm going to be choosing the best path that is under the control of routing protocols that we will see later on so the main responsibility of layer three is what logical addressing and best path determination clear yes okay now I believe this is enough for today because it might eat up the whole brain okay I have some question just give me a minute just give me a let me store this one okay uh class H yes SES please please go with your questions oh yeah um so that uh OSI model that you discussed there is seven layers um is that um like we discuss today physical layers right data link layer data link layers and network network layer that's all so this is going from the from the top to bottom or bottom to top bottom to right see from my perspective see people okay I'll tell you I'll give you a small example yes so uh most of the countries we write left to left to right right A B C D E F G H I J K L this is how we write right but whereas in some countries they will start writing from like this correct or not oh I didn't know that okay oh in the entire Middle East they write from right to left the Arabs Arabic Arabic right to Arabic right to left I know okay now from that perspective which one is first the rightmost is one correct from the countries where you go left left to right which one is first leftmost one is the uh the first one correct now right yeah okay now the point is what is the purpose of OSI data communication correct from data communication perspective not from the applications usage perspective data Communications perspective which layer would be the first layer physical layer that's why they referred physical layer as layer one okay so today we have gone through application sorry uh the physical data link and Link and network these three layers we have seen all right in our next class we will go through the other but I would request you to go through uh the the the first video that would help you to recollect all the content what we have seen today can you do that y if it is over if you feel that it is overloaded it is still okay to go through it just listen to it don't worry about anything the video today video One video only one video not today's video the video what I have shared in the last class there were three videos I am asking you to watch watch one video okay that will be make sense more now than we uh watched it before that would be helping you a lot to proceed further MH take some break when you get some free time today watch that video still I would recommend don't watch continuously MH once the physical layer is over give a break mhm maybe some 10 15 minutes of break or 5 minutes or 2 minutes whatever you feel like that then start data link layer once the data link layer discussion is over give a break then go to the network layer and then stop there

2023-11-19 18:59

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