Clients, Servers, and Protocols | Cisco CCNA 200-301Feb 02, 2022
and welcome to all. I can go ahead and bookmark my screens here. Hey, it's great to have you. Thanks for joining me on CCNA Sunday. Everything related to CCNA and our objectives. The next probably a couple three months of topics I'd like to cover from CCNA
ciscocertified network associate and I'm going to pick a little bit and create content that I wish someone would have created for me almost two and -half decades ago when I started to learn Cisco and started to get involved with it so our goals are these here pretty straightforward let me just go ahead and hide this layer as I talk this way through our goals are for us at the end of our short time together today , I'd love for either of us to describe what a client or a server is, if I'm sorry say we can say oh I know exactly what that means and how it fits together. what is the benefit of a layer or what is even a layer and then what is a protocol stack so those are our goals we'll come back at the end of the stream and confirm that we're all comfortable with those topics and we're going to build a piece logic at a time so let's go to this grid and let me bring a little pen so I can write some of this down and they bring it up there and this is a pen that allows me to write on top of everything which is absolutely wonderful so come on Start with the concept of and it's a lot like going to a restaurant.
Let's talk about that for a moment regarding
clients. If you and I have a full-time job, one of my first jobs at it, I guess. It was in the late 70s, one of my first jobs was picking up plates, a busboy at a restaurant in Camarillo, California, and I would prepare the dishes and bring them back and then I got better. I got a better job as a waiter. Couldn't serve alcohol. and the old but as I got older I was a waiter and so if you and I walked into a restaurant and someone came to take our order you are providing us a service so in that context we or the customer we as the customer we would be the customer and the waiter would provide the service now behind the waiters there are also people who are preparing the food and doing a bunch of other things to deliver that food to us so in a computer network every time we think about the concept of a server it's a device that provides a network function or service let's take a closer look at our diagram and make sure we're both clear on that idea so let's take this server right here so when we say a public server that implies that we have a server that the public can access, in this case, that people on the internet can access.
So, in terms of what kind of service a server could provide, let's talk about some of the more common ones, for example web services. I mean, just think about the last time you visited a website. Well we mainly like Keith like two seconds ago when I got into the stream or saw this video yeah that's a great example or we might have some kind of file services we're getting online or we might have some kind of file service streaming that we're receiving or we might have some kind of a service so basically a server provides some functionality some service that we're consuming so file services and web services are great ways to think about that to keep things in order , like any device on the network that provides a service that provides information. providing a function can be thought of as a server right now, so if we have one of these devices and let's say it's a web server that's currently acting as a server, let's take a look next at
clients, so the clients would be someone who is requesting the services that's all so if we go back to look at our topology a client could be like this guy here now in my could get to I'll tell you a little secret and my when I discuss networking and talk about the usersUsually I use one of two users I use Bob or Louis and I'm going to reveal why that's my father who is 90 his name is Bob and his last is Barker so it's kind of funny anyway it's not Bob Barker himself. but my mom's name is Lois and so I use Bob and Lois as individuals as examples of users on the web, so what it helps me do is what I'm talking about or are we learning about the concepts that I like to involve. and visualize or imagine the actual user using the network because that gives a better or bigger idea of how it works so if we go back to our topology here we have Bob sitting at this computer and Bob opens a browser for that browser there are many browsers out there web browsers things like chrome things like internet explorer and now edge and firefox and safari and other third party browsers but those browsers are programs that run on the computer that act like and can use the
protocolsor use the services de ne work so well with the devices that I was Bob as a client and his software running as a client to reach out and connect to a server and get those services so boom it's on our checklist what is a client or a server is a server is providing some kind of a network service and a customer is consuming or asking or requesting that service no, I have another question for you and that is this and then you clear my screen what if at one point we have a device that is making a request and it turns off? to the internet asking for information and then a moment later it's actually providing a service to another client so maybe it's a device here let's go ahead and choose this device so this is a little Raspberry Pi that has a lot of capabilities, but anyway, let's imagine this is a device and at one point it's providing a network service, maybe someone is connecting to it over the network and requesting web pages and at the same time reaching another device and requesting time services to find out what is the exact time at that time, this device acts as a client and as a server, it acts as a client asking for the time, it also asks how to act as a server when it provides web services, so when we talk about clients and
serversit really depends on the exact moment or what is the function at that moment and many devices actually most devices on networks are acting like some kind of client for something and also like a server if its like a web server or a file server etc and that includes streaming so if you're a fortnight fan there are servers that provide those services and your client your PCs act as clients requesting and consuming those services as you interact and smash the game is ok i like it for tonight.
I'm not good for tonight but it's amazing and check this out too. I have some family members who are really into gaming and whenever the network is down or they feel like it. Hey, this is not working right. I'll tell you one of the main benefits of really understanding how all the pieces fit together is that when something goes wrong, you can check your end. You are part. the four steps I'm responsible for my computer as a client on this network let me check those four things and check that there isn't a problem locally and then if it's on the internet or the remote servers there's not much we can do but the good stuff is that you can check locally once we understand the pieces that's the benefit of the second part here that I'd like to talk about and that's the benefit of the layers and let me go and bring the screen back up so the layers are awesome and you might think well Keith, what do you mean by layers?
If it's cold, we should have layers so we know to keep warm or keep cool. Yes, there are layers in that sense as well, but there's also the concept of individual components or pieces that can all work together. Since we don't have to understand it all at once, a great analogy is, as we imagine, just recording what Sunday is. So on Thursday my wife and I flew to San Fran
ciscofor a couple of days to see some friends see a Cirque. du Soleil who was there Anna Luna was so much fun and we also got to go see a movie and this movie was actually a movie on the big screen at Symphony Hall in San Francisco if you ever get a chance to do this it's so much fun, it was awesome it was like i've never experienced anything like this before so let's consider a theater whether it's the symphony hall or a movie theater you know there's a lot going on and for all of that to happen oh there are concessions you know ?
There is sale of food or snacks and things like that there is sale of tickets. fires in the building and probably exit signs and there's a lot of stuff that goes into a production like that, so whether it's a movie theater or a symphony, there's so much going on that it wouldn't make sense for us to go in and say so yeah we're going to go ahead and define this whole boom, there's everything, every aspect of it, it would make sense for us to take individual parts of that and break it down and then better understand those parts and how those parts all work together which my friend is the benefit of having layers within our computer networks that way we can say oh this is a layer three agreement feature and then we can just focus on that so the The goal here is to see the benefit of the layers and the benefit of the layers is that we take each individual component on its own and then we focus on that part of the network functionality and how it works to really understand it better, that's goal number two. :understanding the benefit of layers now that I have s help let me show you some layers and a long long time ago in a galaxy far far away I learned Novell and you're thinking what is Novell that's a good question if you're under 40um Novell, I think late 1970s. early eighties was the network operating system on the street and this is before computers had tcp/ip as a protocol that came native with them anyway so in the early days they taught me in my early days of networks to learn what I was referring to as the OSI reference model which is this bad boy right here we pulled out the appropriate tool there we mentioned this so this OSI reference model was a model it's not like nobody really did will use, it's just an idea to fragment or divide the functionality in the network but like that go to a movie theater and then go well here there is a lot of concessions work or go well this is how candles work or this is how the arrangement of the seats and this is how the air conditioning works and so on instead of treating everything like one giant lump we have layers of functionality and this OSI reference model had seven layers and if this is 20 years ago I asked them to memorize that news its not 20 years ago but in the original OSI reference model that still exists as an idea or framework yes there are seven layers so in the old days we memorize them ok ok im going to memorize all seven and we had mnemonics to memorize them, it was a real party nowadays, we don't. we use the OSI reference model literally, but we use something else, we use something called tcp/ip Wow, that's a mouthful of letters, a set of tcp/ip
protocolsand let's take a look, well let's talk about the word protocol first, um , my goal for us. you and I is to look at every component that we are, every aspect that matters to computer networking and make sure that you and I understand that we understand it, it's not like I don't know that I want both of us to know. we're going little by little step by step i want us to be one i'll be very comfortable with the basics and then how the networks work then we'll build on that while you and i enjoy this together and continue so let's talk about when i was young i was born in 1964 a long time ago but when I was young I was in a anyway for some reason I learned Morse code Morse code and Morse code is a combination of dots and dashes so a dot would be represented by touching as once and the dash would be a longer period of time so i learned SOS dot dot dash dash dash dot dot it would sound something like this there we go SOS and that could be very useful at some point if you know if we could communicate with that now SOS is cash only for me to do it or us to do it if we're sending a message and there's someone else listening to that message and who's the word I'm looking for understands it so if you and I are the only two people on the planet who understand you They understand SOS and the set of rules for how it works, it's not going to be very effective and unless I know they're talking to each other, we can't talk to the outside world, but luckily there are plenty of people they know, at least in the past. , that they learned in the military that they learned SOS or they learned Morse code and so the benefit is that we have a set of rules for how Morse code works as SOS, so we're using the correct rules to say SOS in Morse code and then something else that understands that same set of rules could interpret that sayingoh that means SOS cool so what? has that to do with SSO networks Morse code is an example of a protocol a protocol is a fancy word PR OT or co L is a fancy word meaning rules a set of rules or agreements so someone somewhere developed Morse code and agreed to it as a protocol that they could use with other people who also understood that set of rules that protocol and then they can talk back and forth now here's the cool thing with networking there are protocols that it's a way elegant to say one set of rules many sets of different rules that if followed by one device, another device on the network can interpret what that means and that's how we can move data back and forth following the same set of protocols, for example so that's our other goal for today was to understand what exactly is a protocol and a protocol is a set of rules that two parties on the network agree to and the network p You can allow those devices to communicate because it's like Morse code, they understand how each other communicates because of the rules of the protocols and then they can communicate with each other following those same sets of rules, so as I look at my notes here, our goals were to identify you know what exactly that client or server is, a server is a device that provides a network service like a web server. we are uploading to google web server or dns server sales and we are getting responses we are acting as a client it is acting as a server and we are having network communication the reason it works is because we have protocols that our browser is using in the background flat, so we open our browser, we go to WWE, my favorite website.
The magic of the course is a set of many sets of rules or behind the scenes protocols that are agreed upon and used and that's why it's working and as we go through these CCNA Sundays together we're going to take a look at the individual like us. i will specialize in individual areas of the overall function of the network how it works and some of those areas will involve the layers and the ectomy let me clean this up to an appropriate level so that it makes sense let me pull out my one of my favorite tools and one of my favorite tools favorites with annotation here is the eraser tool so you mean Keith we don't have to memorize the OSI reference model and I say correct because that was a long time ago I'm going to show you with you here in a moment something that's important to remember but no it's the OSI literally so we don't need to memorize the OSI reference model and at the same time the OSI reference model was promoted as a framework or an idea of how to know Consider the individual compartments or components of a network functionality.
The tcp/ip protocol stack was being developed by the US government Department of Defense stack let's break that down the protocol is just an agreement write a set of rules we agree to and a protocol we as a set of agreements that all work together, we could call it a stack of agreements that all work together or we could call it a protocol stack, so when someone says a protocol stack, they're basically saying a different set of rules that are designed to interoperate, work and cooperate with each other so that we can demystify that. t and not have to worry about it every time we hear the word protocol or indeed anywhere coding programming networking the word protocol simply means a predefined set of rules that hopefully at least two devices are more okay and then they can follow those rules those protocols for success so whether we're writing software applications or automating a network or changing the configuration of the Cisco router or switch, we're just configuring and working with the protocols to cooperate and work with each other back to the beginning. blackboard here so we used the tcp/ip protocol stack however we thought you know how cool it is that the OSI reference model layered individual functionality so what they did was and I like that it's also cleared because this here is no longer I mean unless you just let me ask you a trivia question that it's not about here we are about how networks work how we get good at working with them and that v value we bring because we understand how it works the network and eventually how to set them up and fix them, yeah that makes us more valuable, makes us more valuable to ourselves and our families and our employers and makes work fun because there's a problem or something.
It occurs to me, oh yeah, I actually when I troubleshoot all the time with computer networks and that's because things don't always go right, but when something goes wrong, like there's a player inside of me under a hundred feet and the players like that ah I just know that player lost something or there's a network issue and I can dive in and say ok great lemme check the Wi-Fi lemme check the ethernet lemme check the speeds here let me check this distances and i can identify if it's a local problem and it's not a local problem then it's out of our control sometimes but it's good it's good and i like it as VR too mm-hmm i enjoy virtual reality um it's so awesome so you put I h ave a search headset it's end of 2019 probably a year or two there would be something awesome even better anyway it's fantastic but if I analyze that network traffic and what's really happening is that it's still using this stack of protocols and this set of rules the answer is yes, yes it is, so this information will benefit you whether you are supporting a network in the corporate environment or at home or at a friend's house or wherever it's really good to get a feel for how all these layers work together which we'll do separately in later videos so going back to our drawing here we have these one, two, three, four, these five categories of functionality and I'm not going to ask you to memorize them yet because what I would like to do is point out in the networking world we have these layers and let me change that color that would be great mention this and let me use the there we go. like at the application layer there are protocol sets or rules and programs and applications and services that can be run to provide network services so let's imagine we have a user like Bob and now that's and now that's our insight joke for right so we have it and then me my dad is amazing he's 90 he can do VR standing up his balance is amazing and I also compete with him for exercise like number of minutes standing etc. your computer and Bob open your favorite browser and this is just one example of how a protocol stack a protocol suite can interoperate working together and we'll cover the individual details of each of these layers in later live streams so Bob is the browser that you can imagine what you would like it to be, it could be Safari, it could be Chrome, it could be edge, it could be Firefox, whatever browser you know Bob chose to use now behind the scenes if Bob goes to www.vitac.com, so it goes to the F av site comm and then behind the scenes which will translate to an IP address which we'll talk more about too so behind the scenes humans like to use names like save site comm or twitch comm or YouTube easy but behind the scenes Behind every name is an IP address.
IP is an acronym for Internet Protocol address. It is like a street and the name of the house is a number. you have with your neighbors and that's what IP addresses are all about we'll take a closer look at that too okay but behind the scenes when Bob makes that request what his computer is actually doing is using an application layer service called web services and they have a fancy name for that and that name is HTTP or HTTP Hypertext Transfer Protocol and these are just examples well we'll look at each of these layers separately and then with that application layer service of a service you can be providing the web service if bob is requesting before bob spits that packet or that information out of the network so lets say bob is connected to a switch a switch is a network device that can forward traffic in the right direction we could also have a router the router is also another network device that can forward traffic in the right direction so let's imagine Bob is up here and Bob is up here You want to go to this server at your favorite communication site long behind the scenes before your computer starts spitting that information out on the network, your computer will take that request at the application layer and do something called encapsulation, which means it will add information based on layer 4 and there are a couple of major protocols here on layer 4 and we will have separate videos on all of those one of them is TCP it stands for Transmission Control Protocol and if you and I were to send a letter very important to someone and we wanted to make sure you got there we could ask for a receipt you know I guaranteed delivery with a receipt and that's what the transmission control protocol at the transport layer does here in this tcp/ protocol stack ip is reliable can you basically make sure it's ok talk to that person on the other end the server also gets little receipts from time to time to confirm oh yeah got it alright, here's more and so on, so basically before Bob sends his data out to the network, not only is he requesting a web service, but he's also going to use another protocol, another set of rules that will verify that the information arrived there and the response came back and everything else behind the scenes, so Bob just happily goes, but behind the scenes we're going to use other protocols at the various layers so that the traffic continues to run in the brain of the computer and the browser of Bob, it will also include information about the addresses involved, the IP addresses, and so it's g I'm going to add Bob's source IP address, so I'm putting out a letter if you and I were to send letters back and forth to each other through the mail.
It would put your IP address as the destination if you send it. in a message to me i would put it in my ip address for my house number and street name so basically ip addressing looks a lot like street names and house numbers, and it must be added or included before Bob spits it out on the network. because network devices need information to go ahead and forward it and then as Bob's computer continues to think about this, he asked me to set that it will also go ahead and include something called a layer 2 address or MAC address and we're going to save all those details for the next series that is going to happen on mire mi sunday xi 8 basic 8 sorry i will look at the date for next sunday but it will be at 11am. next Sunday will be our next dream.
When are you going to start it in layer 2 for Bob to include all that information? and then Bob spits that information out on the network and then the network devices forward it in the address of the server which then opens it and sees the request and then responds back to Bob for the actual details about these protocols these rules that happen on every of these respective layers we're going to save that for future discussions and then the good thing is we don't have to master it all of us can say ok great let's focus on knowing what happens in layer 2 why?
It's important what happens there and we'll do this in our treatment for layer 3 what happens there and layer 4 and the application layer, so there are three basic things that I wanted us to take away from this chat. This discussion first was clients and servers. a client is making some sort of network request, whether it's to a file server, web server, twitch server, or some other stream or something else, it's making the request and the server provides the response based on the request second thing I'd like to do is have a chat with you about the benefit of layers the benefit of layers is we don't have to understand everything at once we can say you know what I understand there are some basic layers separated the compartments are departments within network operations and now that I understand that protocols are simply rules that work together in our next transmission, we can focus on how each of those protocols and which protocols are protocols like HTTP and protocols like TCP and IP , etc., because those are all the protocol rule sets that we use to communicate over a network and the third thing I want to do is take advantage of the benefits of layers and then also demystifying the protocol stack so that a protocol stack is a grouping of rules or protocols that can work together and interoperate together and as we continue these CCNA Sundays we'll go into layer two and see what it happens there with examples you also know what we can also use protocol analyzers it's also one thing to understand the concept of well there are layers and this is what happens in that layer but it's another thing to actually see it and you might say well Keith how we see you? we know that thecomputer is doing all this work and all these elements of the protocol stack working together, it spits out the information from the network on the network, how do we see it? and the answer is we collect that information from the network and then we have a program called a protocol analyzer or a packet capture software that can show us the details so that it becomes more than just a theory we can actually see oh , here are the things in this layer and here are the things in this layer like the application layer and the transport layer and the IP layer Network layer and we can look at it to reinforce the concepts so we'll take them step by step to as they come and those were our three goals that I wanted to address and cover in this live stream. m as a warm up for ccmn and these concepts for the way they apply to all things IP so whether you're looking for CCNA or Network Plus or just want to know more about how the network works as we dive in, we'll go through each of the layers and also what you and I can do to troubleshoot and verify that those layers are working properly if something crashes because it wasn't above the collision overnight and it's working so let me go ahead and mention our targets one more time just to confirm and here they are yes they are there yes let me undo. of that later ok what are the roles of clients and servers or benefits of layers and what is a protocol stack so i guess as proof of how we did it collectively one of the things i would do is maybe a friend, a loved one, a spouse, a partner, anyone who chats with you for a moment and I encourage you to take up the challenge of explaining these things to a non-IT person, what are the roles or the what you know about a client or server what makes a device the client or what makes a device deserves to see what is the benefit of layers and what is a protocol stack I put it in quotes because really a protocol is something just a set of rules and a rule stack is just a set of rules that cooperate and interact with each other so the benefit of chatting with someone else and walking them through this is it can help identify areas like oh what how did it work to that again? this video upload to this live stream also what i would love for you to do and what i would love for you to do is in the comments section to know for this presentation because im talking to you like 100 percent i haven't had a chance to see the comments yet, so I'll get to them in a bit, but if you see a comment, whether it's this live stream or it's posted and something has a comment and you know the answer, it's me. as a question, my encouragement is to jump in and answer it to help the I help your neighbor, your brother, your sister, or your fellow human as they begin to internalize this and better understand it.
This is a fantastic journey into the world of networking. I'm lovin 'it. I'm lovin 'it. So what does that do? I'm going to play some music for a few moments and I'm going to take a look at the cube real quick to see if there are any burning questions that I need to answer right away for us here on the live stream and then I'll come back with a follow up idea. about a couple of things I'm creating that I think you'll love too so give me a moment I'll put some music on and I'll be back right away and I want to I want to think wow there's a number of people who have responded oh nothing Mike way to go ha ha Mike there yeah answered questions and I appreciate that that's great and I'm looking at the responses.
Mike your perfect for anyone looking for CCNP and they are half way there before 2020 feb 2020 is there a tool c Alled a Cisco migration tool hmm is it called a cisco migration or cisco cert tool? Let me quickly look it up and I'll actually add it to a comment on this once it's posted as a recording. I'll go ahead and add that URL. so it can find it and show you exactly what weight you have taken so far based on the checkboxes and then what you will get after 24th Feb 2020 as a result ok thank you very much.
I know other people who are studying and learning fantastically so next week the 15th is what I see as the calendar item for that let me verify yes the 15th is next Sunday so what we'll do is cover the level up to our layer let's do a quick overview of the protocol stack and how the pieces can work together and we'll focus on layer 2 you know I say we'll keep layer 2 well it's not on the serious note it is layer 2 fucking awesome layer 2 deals with switches layer 2 switches that forward b-frames based on destination layer 2 addresses and also deals with things like virtual local area network VLANs which I don't know why, but the word vlan is just awesome to me i like it it's like villains it's cool also the concept of trunking is there so i can break them into separate sections but i want to make a really good discussion about layer 2 peer So that you fully understand that when Bob sends a frame to the switch, those bits how frames make forwarding decisions here's a little spoiler alert that they use the layer.
A layer 2 switch uses the layer 2 address for forwarding and then we'll follow that in a later live stream on layer 3 routing and IP addressing and the transport layer and the application layer so for when we do. Done, if you hang out with me every week for a few minutes, you'll get really comfortable with how the protocol stack works, how the pieces of the parts fit together, and, well, then take that and we'll start applying it on a Cisco c. core network interface our architecture, which would also apply to Juniper, HP, Palo Alto, Citrix, and other vendors, so the concepts we're going to learn about IP networks apply as well, we'll also look at ipv6 as we take a look at layer 3 so I'll see you Ray next Sunday same hitting time same hitting channel also if you're interested I'll do that on Wednesdays at 4pm too and I will also post an ad.
I'm doing this behind this behind the scenes. A sneak peek at some of the content I'm creating on CBT Nuggets regarding CCA and development network programs. I can stuff that hasn't been released yet for you to have as an insider's behind the scenes look at what it is and what's going on so I wanted to keep this close to 30 minutes. I think we did pretty well. again thanks for the support on the backend having a community helping each other with questions and confirming love it so have a great rest of your day thanks for joining me for this live stream on CCA and then the link will be oh gee I teach online slash CCNA zero one any guess what's next any guess what's next yes zero two that way I'll also be super easy to find and that way when they're done you can have a full stream or an entire series in order of content regarding cisco c certified network associate and most importantly the technology and skills to be able to understand it, configure it and hopefully with enough knowledge and practice also fix it, you are ok thanks everyone see you on the next live stream.
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