Network Protocol Stack

If you’renew to networking or studying for a certification like CCNA, Network + or JNCIA this is a great place to start. For the first few I’m going to assume that you have no networking experience.My goal is to create a solid foundation for you to build on. In this Post we’regoing to start with understanding what a network actually is and some of thenetwork types you’ll see. We will follow up in part two with a look at how a networkmay be cabled and get an overview of addresses.

What is a Network? So maybe you already know what a network is. Maybe you’ve built your own network at home or help someone to run thenetwork at school or at your job. That’s okay I don’t want to bore you so if thisapplies to you I would like to give you this challenge pause the video and thinkof a good description of what a network is if you’ve come up with somethingyou’re happy with well done feel free to skip ahead otherwise stay with me andI’ll see if I can come up with something for you at work or home you have a bunch of devices computers printers TVs and so on you connect these by means of anetwork when the devices are connected they’re able to share data this could besending a print job to a printer sending an email or streaming video this can also be used for sharing an internet connectionmostly network users are unaware of the network they’re using as long as theycan browse the Internet do their job browse YouTube they’re usually fine forall of these devices to communicate they need to be connected together somehowone way sir plug cables into the devices and connect them to another device called a switch an example is in a school’s computer lab in this case acomputer in the lab connects to a wall socket with a cable another cable runsthrough the wall which comes out at a patch panel this may be in a cabinet onthe wall somewhere in the room or in another room entirely the port on thepatch panel then connects to the switch you might have a switch at home too mosthomes don’t have wall sockets so devices are connected directly to the switchwe’ll talk more about how switches work later we can also connect deviceswirelessly a common way to do this is to use a wireless access point a wirelessnetwork like this is also called Wi-Fi.

An example of this is if you have atablet it is impractical to cable it in so Wireless is a good option the accesspoint is like a switch without cables more than one device can connect to theaccess point over time but without the messy cabling the access point can alsobe connected to the switch with a cable this way wired and wireless devices canall be part of the same network having both wired switches and wires accesspoints gives you more connection options imagine you have a laptop in an office.

You may connect it to the network with a cable when you’re at your desk when youhave a meeting in the conference room you remove the cable and connect toWi-Fi where the wired or wireless the goal of the network is to moveinformation from one device to another for this to work the sender and thereceiver must understand each other they need to speak the same language in thenetwork speaking the same language means that devices agree on how data is sentreceived organized and handled basically they agree on a process that they allfollow it’s a bit like filling out paperwork this is called a protocol.

A lot of different protocols are used depending on what’s needed at the timenetwork software and hardware are designed with these protocols in mindyou will hear of protocols like Ethernet and TCP which are used for sending andreceiving data you may also hear of protocols like HTTP which is used foraccessing the web and SMTP which is used for email usually several protocols areused together to achieve a task we look at protocols further in future videos in summary networks are used to connectdevices together devices use the network to communicate and to share informationto share information devices need to speak the same language this language iscalled a protocol which is a set of instructions of how to handle theinformation we’re going to start with some simplequestions to get the brain working.

Firstly what are the two ways computerscan connect to the network to follow on from that what devices do they usuallyconnect to and finally how many protocols are used when one computeraccesses another computer when you’re ready to see the answers follow the linkat the bottom of the screen that works connect devices you could call deviceson the network nodes nodes may include devices that help control the trafficflowing through a network like switches and routers nodes also include endpoints or hosts these are devices that send and receive the bulk of the trafficthis includes workstations servers printers and so on now works come indifferent sizes a network at home is an example of a small network thesenetworks usually only have a few nodes this is called a Soho Network.

Soho means small office home office these networks typically have a couple of computers aprinter a few phones and tablets some devices will be wireless and some are connected to a switch this might be a good time to mention that people oftensay hub when they mean switch you can see why of course as the switch lookslike a central hub in a Soho Network but please keep in mind that switches andhubs are very different things hubs are really old technology that yougenerally don’t see anymore outside of a museum while switches are modern and commonly used they look very similar so it’s easy to mix them up have a look atthe model number to see if it gives you any clues about what the device reallyis in a Soho Network a router is used to connect to the internet you might findthat the router switch access point are all integrated into onedevice also her network will only have a fewdevices a corporation for example the bank will have many devices this is called an enterprise network.

The enterprise network may cover severalfloors in a building there may also have several office buildings in differentcities or even across different countries an internet provider has avery large network this is called a service provider network not only dothey provide Internet access they also offer services to connecttheir customers together consider the bank with offices all around the countrythe service provider uses part of their network to join these officers togetherwhen devices are collected into a local area we call this a local area networkor LAN the land may be a small network in a Soho Network the LAN is the switchwith the handful of devices connected or the land may be part of a bigger networklike an enterprise network this network may have many switches routers andaccess points depending on their needs think of the bank from before they havean office with several floors you could consider the whole building as a LAN ormore likely the network is broken up into smaller parts perhaps there is aseparate network on each floor each of these could also be called the LAN.

the seseparate LANs may be connected together but we’ll talk more about that later buta banks network is going to be larger than just one building banks haveoffices all over the country and all over the world even though they are farapart these networks can be joined together this is called a win or widearea network imagine for a moment that you work for a company with an office inSydney and an office in Melbourne you could contact a service provider andthey can connect these officers for you where’s there a topic all of their ownso we’ll cover them in detail in a later.

let’s take a moment for a quick summaryall networks are different and this includes their size a Soho Network isvery small while an enterprise network may be verylarge of course your network could fit in anywhere in between a LAN or localarea network is a collection of network devices in a local area like a singlebuilding a when or wide area network connects networks that are far apart andonce again it’s time to get the brain working here’s something to think aboutyou work for a company that has a finance division an engineering divisionand an admin division each group have their own network and the networks arejoined together is this network still a LAN or is it something else entirely thecompany grows and adds a retail division in addition to the head office there isnow six branch offices what type of network is this as before go to the linkbelow to see the answers I hope you’ve enjoyed part one of thisseries join me in part two where we’ll have a look at different types ofcabling the Ethernet protocol and a bit of an introduction into network addressing.

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