What is a SWITCH? // FREE CCNA // Day 1

Summary

This script kicks off a free CCNA course with a special thanks to Boson Software for sponsorship. It delves into the fundamentals of network switches, contrasting them with hubs and highlighting the switch's intelligence in managing data traffic efficiently. The video guides viewers through hands-on experience with Cisco Packet Tracer, exploring the concept of MAC addresses, the CAM table, and the basics of networking layers. It concludes with a quiz from Boson's renowned CCNA practice exam, emphasizing the importance of understanding switches for networking professionals.

Takeaways

• 🎓 The video is part of a free CCNA course sponsored by Boson Software, who provide CCNA and CCNP labs and practice exams.
• 🔍 The course begins by exploring the function and importance of network switches, emphasizing their role in connecting devices and facilitating communication.
• 🧩 Cisco Packet Tracer is introduced as a tool for analyzing network traffic and learning about the operation of switches and hubs.
• 📚 The script explains the difference between switches and hubs, highlighting the intelligence of switches versus the broadcast nature of hubs.
• 💡 It's revealed that switches operate at Layer 2 (data link layer) of the OSI model, utilizing MAC addresses to manage network traffic efficiently.
• 🖥️ The video demonstrates the use of Cisco CLI commands, starting with 'show mac address-table', to inspect a switch's content addressable memory (CAM) table.
• 🔑 MAC addresses, also known as Layer 2 addresses, are unique identifiers for network devices, used by switches to forward messages to the correct port.
• 📶 The script touches on wireless access points, noting their similarity to hubs in terms of broadcasting signals to all devices, unlike the direct communication of switches.
• 🛑 The disadvantages of hubs, such as traffic jams and collisions, are contrasted with the efficiency and reduced collision domain of switches.
• 📚 The video includes a quiz with questions from Boson XM, a renowned source for CCNA practice exams, to test understanding of switch operations and the CAM table.
• 🔗 The importance of preferring wired Ethernet connections over wireless for reliability and performance in network communication is emphasized.

Q & A

What is the main focus of the first day of the CCNA course?

The main focus of the first day of the CCNA course is to introduce the concept of a switch, how it works, and its importance in networking.

Who is the official sponsor of the CCNA course mentioned in the script?

Boson Software is the official sponsor of the CCNA course.

What tool is recommended for analyzing frames and packets going across the network?

Cisco Packet Tracer is the tool recommended for analyzing frames and packets going across the network.

What is the difference between a switch and a hub in terms of functionality?

A switch is a smart device that learns and forwards messages only to the intended recipient based on MAC addresses, whereas a hub is a dumb device that broadcasts messages to all connected devices.

What is the purpose of the Cisco CLI command 'show mac address-table'?

The 'show mac address-table' command is used to display the switch's CAM table, which shows the MAC address to switch port assignments.

Why are switches considered more secure than hubs in a network?

Switches are considered more secure than hubs because they only send messages to the intended recipient's port, preventing unauthorized access to the data being transmitted.

What does the acronym 'CCNA' stand for?

CCNA stands for Cisco Certified Network Associate.

What is the significance of a MAC address in the context of a switch?

A MAC address is a unique identifier for network devices. Switches use MAC addresses to learn which devices are connected to which ports and to forward frames to the correct destination.

How does the script describe the process of sending a message between two devices using a switch?

The script describes the process as sending a message (frame) from one device to the switch, which then forwards the message to the intended recipient based on the MAC address stored in its CAM table.

What is the difference between a frame and a packet in the context of networking layers?

In the context of networking layers, a frame is a unit of data specific to Layer 2 (the Data Link Layer), while a packet is a unit of data that includes Layer 3 (the Network Layer) information, such as IP addresses.

Why are wired connections often preferred over wireless connections in certain scenarios?

Wired connections are often preferred over wireless connections because they can provide a more secure and stable connection, avoiding the issues of broadcast to multiple devices and potential traffic jams or collisions that can occur in wireless networks.

How does the script introduce the concept of layers in the OSI model?

The script introduces the concept of layers in the OSI model by discussing Layer 1 (the Physical Layer), which deals with the physical aspects of networking like electrical signals and cables, and Layer 2 (the Data Link Layer), which involves MAC addresses and frame forwarding by switches.

Outlines

00:00

🌐 Introduction to CCNA and Networking Basics

The video begins with an introduction to a free CCNA course, sponsored by Boson Software. The speaker emphasizes the importance of switches in networking, explaining their function and the excitement of learning through hands-on labs using Cisco Packet Tracer. The concept of 'labbing' is introduced, and the audience is encouraged to explore the depths of networking, likening it to taking a red pill from the Matrix. The summary of a previous video on network components is provided, and the video promises a deeper dive into the subject matter.

05:04

🔌 Understanding Ethernet Cables and Switches

This paragraph delves into the physical aspects of networking, focusing on Ethernet cables and switches. It explains how switches enable computers to communicate using electrical signals through these cables. The speaker uses an analogy of sending a text to illustrate the concept of data transmission. Different switch sizes are introduced, with an 8-port and a 48-port switch being highlighted. The importance of understanding the inner workings of a switch is emphasized, and viewers are encouraged to download Cisco Packet Tracer for a practical demonstration.

10:04

📡 Transition from Hubs to Switches in Networking

The speaker contrasts the functionality of hubs and switches, describing hubs as the predecessor to switches. Hubs are characterized as 'dumb' and less efficient, broadcasting signals to all connected devices regardless of the intended recipient. The audience is invited to experience the limitations of hubs firsthand using Cisco Packet Tracer. The video then demonstrates the superior intelligence of switches, which can direct data to specific devices, improving efficiency and security.

15:06

📱 MAC Addresses and Layer 2 Communication

This section introduces the concept of MAC addresses, also known as Layer 2 addresses, which are unique identifiers for devices connected to a network. The speaker explains that switches use MAC addresses to learn and remember the location of devices, storing this information in a CAM table. The difference between Layer 1 (physical layer) and Layer 2 (data link layer) is discussed, with Layer 2 being where MAC addresses play a crucial role in communication.

20:06

📶 Comparing Wired and Wireless Networking

The video touches on wireless access points, comparing their behavior to that of hubs rather than switches. Wireless access points are shown to broadcast signals to all devices, similar to hubs, which can lead to traffic jams and collisions. The speaker advises preferring wired connections for their reliability and efficiency. The limitations of wireless networking are acknowledged, and the benefits of Ethernet cables are highlighted.

📝 Quiz and Conclusion of CCNA Day One

The video concludes with a quiz based on the material covered, sourced from Boson's renowned CCNA practice exams. The questions focus on understanding how switches use MAC addresses to populate their CAM tables and make forwarding decisions. The speaker reviews the correct answers and provides explanations to reinforce the learning. The video wraps up with a summary of the topics covered on 'CCNA Day One' and a teaser for upcoming videos on routers and the OSI model.

Keywords

💡CCNA

CCNA stands for Cisco Certified Network Associate, which is an entry-level certification program for network engineers offered by Cisco Systems. In the video's context, it is the main subject of the course being introduced, with the goal of teaching viewers the fundamentals of networking. The script mentions it as the course's title and discusses the importance of understanding its concepts, such as switches and networking devices.

💡Boson Software

Boson Software is highlighted in the script as the official sponsor of the CCNA course. They are recognized for providing CCNA and CCNP labs and practice exams. The script encourages viewers to check out Boson Software, indicating their support as a key reason the course can be offered for free.

💡Switch

A switch is a networking device that connects devices together on a computer network, allowing them to send and receive data. In the video, the switch is described as 'amazing' and is the central topic of the first day's lesson. The script explains how a switch operates, its differences from a hub, and its importance in modern networking.

💡Cisco Packet Tracer

Cisco Packet Tracer is a network simulation tool used to create and analyze network scenarios. The script introduces it as a tool that viewers will use to analyze frames and packets going across the network, emphasizing its role in providing hands-on experience with networking concepts.

💡Ethernet Cable

An Ethernet cable is a type of cable used to connect devices to a local area network. The script mentions it as the physical medium through which computers communicate with each other via electrical signals, highlighting its fundamental role in networking.

💡MAC Address

A MAC (Media Access Control) address is a unique identifier assigned to network interfaces for communications on the physical network segment. The script explains that switches use MAC addresses to learn and forward messages to the correct devices, emphasizing its importance in the functioning of switches.

💡Layer 2

Layer 2, also known as the Data Link Layer, is part of the OSI model and is responsible for node-to-node data transfer. The script discusses Layer 2 in the context of switches and MAC addresses, explaining how it operates within the networking framework.

💡Hub

A hub is a simple networking device that connects multiple devices together but does not manage the traffic between them. The script contrasts the 'dumb' nature of hubs with the 'smart' functionality of switches, illustrating the evolution from hubs to switches in networking technology.

💡Wireless Access Point

A wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi. The script mentions access points in the context of wireless networking, noting their similarity to hubs in terms of broadcasting signals to all devices.

💡Packet

A packet is a unit of data sent across an network. The script uses the term 'packet' to describe the data being sent between devices, particularly when discussing Layer 3 communication, and distinguishes it from 'frames' used in Layer 2 communication.

💡CLI Command

A CLI (Command Line Interface) command is a directive given to a computer program through a command line interface. The script introduces the first CLI command 'show mac address-table' used to view the switch's CAM table, demonstrating an interactive way to learn about network devices.

Highlights

Introduction to a free CCNA course sponsored by Boson Software, offering the best CCNA and CCNP labs and practice exams.

Explanation of what a switch is and its fundamental role in connecting devices within a network.

The importance of Cisco Packet Tracer as a tool for analyzing network traffic and understanding how switches operate.

The concept of 'labbing' and its significance in the learning process of networking.

The introduction of the Cisco CLI command and its role in interacting with network devices.

A comparison between switches and hubs, highlighting the intelligence and efficiency of switches.

The demonstration of how a switch works using Cisco Packet Tracer to show the flow of data packets.

The difference between a hub's broadcast behavior and a switch's intelligent forwarding of data.

Understanding the function of the CAM table in a switch and its role in remembering device locations.

The distinction between MAC addresses and IP addresses in the context of layer 2 and layer 3 networking.

The process of how a switch learns and updates its CAM table with MAC addresses.

The difference in behavior between wired switches and wireless access points in terms of data transmission.

The impact of wireless networking on security and efficiency compared to wired connections.

The importance of Ethernet cables and the preference for wired connections over wireless for network reliability.

A quiz based on the material covered in the video, sourced from Boson's renowned CCNA practice exams.

The significance of the 'show mac address-table' command in understanding the switch's memory of device locations.

A summary of the key concepts covered in the video, including switches, MAC addresses, and the OSI model layers.

An invitation to follow for upcoming videos on routers and further exploration of the OSI model.

Acknowledgment of Boson Software's sponsorship and promotion of their lab and practice exam software.

Transcripts

this is day one of my free

ccna course and a huge shout out to

boson software the official sponsor of

the ccna course

they are the reason this can be made

available for free so i highly encourage

you to go check them out

they have the absolute best ccna ccnp

labs and practice exams day one we're

not wasting any time

we're getting right into what is this

it's a switch how does it work

why is it amazing because it is amazing

and we'll even get a chance to lab what

does labing mean well you'll find out

we're going to use cisco packet tracer

to analyze frames and packets going

across the network and you're going to

get a chance to enter your first

cisco cli command let's get started

[Music]

in my last video we talked about what a

network is and we followed a call of

duty bullet when i shot it from my

computer

how it goes through my home network to

my brother's network and shoots his

character and we went high level like

router switch firewall access point what

are those things

but we didn't go too deep but now are

you ready we're gonna go just a little

bit deeper it's just like one of those

red pill blue pill situations from the

matrix

after this there is no turning back you

take the red pill

you stay in wonderland and i show you

how deep the rabbit hole goes

you take this pill there's no going back

we're going deep into the networking

rabbit hole

you're going to fall in love and never

look back okay i warned you you're still

watching this that means you want to

keep going

let's do this okay let's talk about

switches first what are they and what

are they doing and

here's one right now this is a switch

it's beautiful isn't it look at this

oh love it now if you watched our last

video you have a high level view of what

a switch is for

what's it doing well it's helping our

computers to connect to each other and

talk and hang out and chat

send data we connect using these

ethernet cables and we plug them into

our ports

oh love that sound here listen to this

up close

asmr version uh one of my favorite

sounds

so we connect one computer connects

another computer and assuming we have

computers on the other ends of these

they're talking they're having fun

they're playing games but what's really

going on inside of here

let's pop the hood let's take a look oh

by the way switches can come in many

different sizes like this is an 8 port

and this big boy

is a 48 port he's beautiful

[Music]

why do you need 48 ports well so you can

connect 48 different devices to each

other that's why now let's first look at

this guy the ethernet cable

all it is is a bunch of metal wires like

check it out

your computer communicates with the

other computers via electrical signals

and these electrical signals go down

these wires through the cable to the

switch and then it goes to the other

computer it's amazing it's just

electrical signals going in and out of

these ports it's

isn't that cool now switches are amazing

but for you to really appreciate how

amazing they are you need to look at

their predecessor the one that came

before them the hub

he's disgusting he's dumb he doesn't

have any smarts

the switch is smart the hub is not but

before we had switches

hubs are all we had and here's what they

did and why they're dumb now i want you

to actually see how dumb this is and

experience it for yourself so right now

what i want you to do is go download

cisco packet tracer i've got a link

below

sign up for a free account through

netacad and you'll be able to download

it what is this

it's a tool that lets you build and play

with networks and

so much more it's amazing so go download

and install that it's on windows

mac linux and once you install packet

tracer i've got another link below for a

pack a tracer file which is a lab i

built that we can play with right now so

go ahead and download that

and launch it do not get overwhelmed

with all the buttons and options here

i'll walk you through every step

right now if you zoom in right here i've

got two networks i got this one here

which is a switch

and my laptops if i scroll over i've got

another network and it's

not nearly as smart because i'm rocking

a hub now a hub and a switch

physically kind of look the same they

look like this they have ports where you

can plug ethernet cables into

but they're so so different actually we

can look at a hub right now let me click

on the physical button up here

i can click on my home city my corporate

office and then

jump into my wirelink wiring closet and

there it is so you can see switch it's

got ports hubs got ports okay

but why are they different how would you

like this if when you sent a text to

your friend

it didn't just go to your one friend it

went to all your friends

and then when your friend responded back

to you it only went to you but it went

to all your friends as well

that's stupid right like that i would

never use that texting platform that's

what a hub does

check this out and i want you to do this

with me so click on simulation down here

at the bottom right

this is what makes packet tracer so cool

we can analyze the network traffic

slowly as it goes through

the electrical wires it's oh it's

powerful anyways so don't touch that

leave it there i want you to click on

harry potter up here laptop harry

then click on desktop and then click on

command prompt this is very similar to a

windows command prompt it kind of is a

windows command prompt

and what we're going to do is we're

going to have mr harry here talk to ron

over here

through the hub we're going to send a

message that we use in networking all

the time called

a ping message what is that for we use

it to see if other computers or servers

are up

and can be reached kind of like this

ping reply

now you may have noticed i've got a

couple things right here layer two

address and layer three address now

what's an address

well if i wanted to send you a message i

might send it to your email address if i

want to send you a letter i might send

that to your

mailing address it's something unique to

you that allows me to send something to

you

data whatever and in the networking

world it's the same thing now what does

layer 2 and layer 3 mean

we'll cover that here in a bit but just

know that when i'm going to send a ping

message to ron i'm going to be looking

at his

layer 3 address that might look familiar

to you what is that

well that's an ip address you're

probably familiar with that right

harry knows that when he wants to talk

to ron that's his address that's his

phone number that's his mailing address

that's how he gets information to ron

his ip address so here we go we're about

to ping ron now please make sure you

have the simulation button checked not

real time you want simulation

here we go get your command prompt open

we're going to ping ron so i'll type in

ping and the ron's ip address 10.1.2

now watch what happens when i hit enter

boom

a little envelope popped up a little

message we're going to send to ron and

then notice over here we have a little

event timeline where that message is

popped up

we can see the play-by-play here as we

get more advanced and go deeper and

deeper into what's happening which

actually happen in the next video we can

click on these

and look at some hairy details like

what's happening

don't worry about that yet we'll get

into it but it's amazing so harry wrote

his letter he's ready to send it

and if we click on this little advanced

button right here it'll take a step

forward in time let's go ahead and do

that

click advanced boom let's do it one more

time

boom there it goes it's going across the

network electrical signals firing

so now the hub has the message in an

ideal world in a perfect world the hub's

like okay well this message is for ron

i'm going to send it to ron

but the hub's an idiot he's dumb watch

what happens

watch what happens click next and

why did you do that mr hob you sent the

message to everyone

harry's just trying to talk to his buddy

ron and now hermione knows and and

malfoy knows that's

that's bad right now watch what happens

next remember in a ping situation

harry's gonna send a ping

hey you there ron iran's gonna go yes

i'm here but watch this click next

ron does reply perfect but then watch

what the hub does the dummy hub

he since ron's replied out to everyone

why hub why well again the hub has no

smarts he's got no brain

his job is just to repeat that

electrical signal whenever your computer

sends down this wire

the hub is going to go and send out to

everyone this is how we did things for a

long time

now notice that over here harry potter's

got a green check mark going yes yes yes

that message is for me yes yes yes

but then down here malfoy and hermione

have this x

which means that most the time in a hub

environment if a computer got a message

that wasn't

meant for them it would just ignore it

but

you know that's if you're a good person

if you're a hacker like i'm learning

hacking right now if you get a message

like that if you're

able to see everyone's traffic you're

like yes yes give me more i'm gonna hack

all you guys

not a very safe and secure environment

you don't want to text your buddy

something secret and all of a sudden all

your friends know the secret

but now let's look at the switch he

fixes everything go ahead and click on

reset simulation

you can close out harry potter there and

let's scroll on over to the better

environment

the switch environment now here the

switch has the same

goal as the hub just to connect these

computers together so they can talk so

they're doing the same job

just one's really really good at it so

over here let's walk through the same

situation johnny right here is gonna

ping

mark oh hi mark and we'll see what

happens and i'll explain how it happens

here in a moment so go ahead and click

on johnny click on the desktop tab and

then jump into your command prompt we're

going to type

in ping and then mark's ip address right

here is 10.1.1.2

we're going to hit enter and bam

johnny's got a message ready for mark

let's click on next and see what happens

next

next okay there it goes the switch has

it what's it gonna do

boom so much better only mark got it and

then when mark responds

it only goes to johnny that's how it's

supposed to work thank you mr switch

and if you look back at our command

prompt you can see that we sent a ping

message

and then we got a reply from mark from

the ip address

everything's good mark's alive he's like

hey yeah yeah johnny i'm here and if we

click on real time it'll just complete

it like it normally should

bam bam bam really fast because these

electrical signals are going really

really fast down

these wires but that's what's cool about

this packet tracer we can slow down time

bullet time and watch it happen

okay we're about to go deeper we're

about to learn more about how this guy

does things

are you ready let's take a deeper look

the switch can do all this magic because

it has a brain

a brain that can remember things like

hey on my port fa02

that's where johnny lives and on my port

fa01 that's where mark lives

and the same thing goes for denny and

lisa and anyone else who connects to the

switch

he'll remember where they are so when

you send a message he'll go oh well i

know exactly where johnny is he's over

here

port fa02 he stores that information in

something called

the cam table which stands for content

addressable memory

don't worry about that too much right

now we'll cover a lot of that later now

the switch doesn't know

johnny as johnny the switch knows johnny

as

00d097528936

that's how the switch knows johnny has a

layer 2 address that's how the switch

knows mark he doesn't know mark's name

but he doesn't know zero zero e0b0590897

love that guy what are these things

that's called a mac address

often referred to as a layer two address

every single device that you connect to

the internet

has a mac address every one of them like

go ahead and look get your laptop out

look for it like on this phone here that

i would connect to the switch

look right here there's my phone's mac

address right there

it's often referred to as the burned in

address because this address

should never change that's how your

device is identified it's unique

identifier so when i connect my

phone to this switch and my phone tries

to talk to somebody

boom the switch learns hey that phone

which

that phone's name is 9c57803844a

he lives on port 1. so if anybody wants

to talk to him it's gonna be part one

now we'll cover more about layers here

in a moment i'm kind of building up to

that

but this right here doing this and that

wonderful beautiful sound

yes that's this is layer one anything

physical

the the electrical wires the metal wire

that send electrical signals down into

the switch that's layer one

so layer one electrical signals firing

at light speed down ethernet cable

physical

and then we get to our switch and now

we're thinking about layer two

that's where our layer two address comes

in that's where the mac address comes in

layer two is often referred to as the

data link layer but we won't cover too

much on that right now

i have to stop i don't wanna give you

too much right now now you may be

wondering why isn't the switch just

using the

layer three address like what we used

when we pinged 10.1.1.2

why isn't the switch no marked by that

number well the simple answer is that

the switch can't even see that number it

has no idea what it is

you see the switch is a layer 2 device

and doesn't know anything about layer 3

or ip addresses or anything that's why

we're dealing with mac addresses right

now now watch this let's get back to our

packet tracer we're going to do a couple

things here real quick let's click on

simulation mode once more

and let's open up mark we'll go to his

desktop go to his command prompt

and we're going to ping lisa down here

so we'll do ping

10.1.1.5 and hit

enter the message was built now go and

click the forward message real quick

and i want you to click on this this

message right here we have click on it

now as you can see we have seven layers

we're going to be talking about here

very soon but don't don't think about

anything above layer three right now

don't think about that but notice

this message we're sending to the switch

notice what's not there

layer three is missing it's just layer

two

because that's all the switch

understands and also notice the two and

from so right here we have the from

which is the mac address of

mark over here and then the two is to

lisa's mac address down here and if we

go ahead and step forward in time

boom the switch receives it if we click

on that message again we see that switch

receives it

and he knows exactly where to send it

because he remembers where lisa is

and then if we click on that button bam

it goes to lisa now i'm not sure if i

want to show you this yet

yeah let's go ahead and do it so click

on that envelope right there the message

that just arrived to lisa

you can see here that instead of just

having layer one and layer two we now

have layer three

involved because that's a layer that

mark and lisa are talking on layer three

you see we

pinged from mark's ip address 10.1.1.2

to lisa's ip address of 10.1.1.5

and then lisa is sending out a message

see out

to mark at 10.1.1.2 from herself

10.1.1.5 and then we step forward in

time once more

boom we see this message go to the

switch but then if we open that message

oh layer three is gone again it's just

layer two because that's all the switch

cares about is layer two

and that's how he knows where things are

that's where devices are based on their

mac address now go and click on real

time let that finish out and we're gonna

jump into the switch's command line

interface and this might be your first

cisco command kind of exciting so let's

let's open it up

what we're going to do is we're going to

look inside the switch's brain so go and

click on him

and jump to the cli tab this is a whole

new world for you yes okay

now hit enter then type in enable and

hit enter

now you should have a hashtag sign right

there next to your switch here's a

command i want you to enter

show mac dash address dash

table we're looking inside the switch's

brain and looking at his cam table where

he keeps the mac addresses and how they

are assigned to the ports

because mark and lisa just talked the

switch knows that mark

which is referred to as blah blah blah

mac address lives fa01 and then lisa

lives at fa03 and then if we go to denny

over here

and we go to desktop and command prompt

and we try to ping johnny 10.1.1.3

it's going to go through it's being

successful awesome if we jump back into

the switch and hit the up arrow to enter

the same command

hit enter well now the switch knows

where everyone is he knows where johnny

is where denny is or mark and lisa

he learned it stored it in his brain and

now whenever someone sends a message he

goes

i know exactly where they are boom right

there the hub just doesn't do that and

that's the job of the switch

he learns where everyone is by learning

their mac address they're burned in

address

and stores that in his brain is cam

table and marks where they are so

whenever he receives a message

he can forward those messages to the

appropriate people

and not to anyone else that shouldn't

hear about it now when we're talking

about layer two

this message right here is referred to

as a frame all the messages going

through this switch right here are

frames

boom boom boom frames just going around

like crazy because it's layer two when

you think layer two think switch think

frames

switch frames layer two switch frames

layer two is it working is it going in

there but then when the message goes to

lisa and we're talking about ip

addresses in layer three

do you know what it becomes this message

is now a packet

now just so you know when you're talking

to network engineers and other folks

they might refer to layer two messages

the frames they might call those packets

as well

we just get in the habit of it if it's

going across the network and it's going

to people and it's a message

we often just refer to it as packet it

just happens but technically

it's frames layer 2 frames switch layer

2 frames switch

okay now we're gonna talk a little bit

about wireless um here's a

wireless access point little baby cisco

one here's a bigger

cisco one the reason i wanna talk about

them now along with switches is because

they're basically doing the same job as

a switch

but what's funny what's funny is they're

more like a hub

than a switch they're kind of dumb i

mean they're amazing but they're kind of

dumb like a hub let me show you

looking back at packet tracer if i

scroll down just a little bit you can

see i have a little wireless network

here let me add the uh

ip addresses here real quick now what i

want you to do real quick is down here

at the bottom

click on the lightning bolt or harry

potter esque and then click on the

lightning bolt again this is a

connection it's like plugging an

ethernet cable and we're going to plug

it into the

access point here and then plug it into

our switch we talked a little bit about

wireless in the first video but it's

just an extension of the switch so it

connects to the switch with an ethernet

cable and then it connects all the other

devices via

wireless which we know to be airwaves or

radio waves

so most of our devices like our phones

and everything else connect to this

access point

which is connected to a switch now even

though this access point is connected to

a switch

he's actually more like a hub and it's

all about these connections right here

let me show you real quick

i'm gonna have mr denny here i'm gonna

click on denny and launch his laptop

we're going to go into his desktop and

go to his command prompt

and we're going to ping let's say the

first tablet down here 10.1.1.11 so i'll

do ping

10.1.1.11. oh and i forgot to go into

simulation mode let's go to simulation

mode down here

bring denny back up and boom

so as you can see denny's got his packet

ready and he sends

this frame to the switch now if we open

up that frame

what do we see well we see that the

source is indeed

denny over here based on his mac address

and then the destination

well what is that matching let me scroll

down here we can see yeah it does match

the first tablet here so the switch

knows that he lives on this port

connected to the access point but it's

what the access point does with it

that's so

stupid but it's just how wireless is

right now let's skip forward in time

the access point has it now but now

let's see what happens

click next boom and once more

boom

the message was sent to everyone like a

hub now we'll cover

wireless in more detail here later in

this course but just know for now

that's why people tell you plug into an

ethernet cable at all cost if you can

because a wireless

connection is more like a hub and the

fact that all the messages are going to

each device isn't the worst part with

hubs it's just a traffic jam collisions

all the time

which is why switches are great and

we'll cover more on that later but yeah

always prefer ethernet cable a hardline

connection to a wireless connection if

you can

now later versions of wi-fi like wi-fi 6

do help out with this i actually made a

video on wi-fi sticks that you can check

out up there

and then as we step forward a time when

the first tablet sends here's a reply

back

the access point will then send it to

the switch and then the switch like it's

supposed to we'll just send that to

denny

but then we had the same process happen

again when denny does send another ping

hey

hey first tablet are you there the

access point will still broadcast that

doubt out to everyone

all right hope you have your coffee

ready time for a quiz time to test your

knowledge and what we just

covered in this video the questions i'm

about to ask you are not easy

i pulled them from boson xm the best

ccna

practice exam you can find they are

world renowned and they are sponsoring

this video so check out the link below

for that exam

anyways let's see what you know question

number one

which of the following addresses will a

switch use to populate

the cam table select the best answer

if your answer was b source ip address

you are wrong because the answer is in

fact

d source mac address remember switches

layer 2 mac address switches layer 2 mac

address

let's select our answer and get the deep

down dive from boson

so right off the bat because we know

we're talking about a switch in the cam

table we can mark out

a and b because those are talking about

ip addresses and the switch doesn't know

anything about ip addresses but what

we're talking about now is mac addresses

now it could have been source or

destination

a switch will learn a mac address and

add it to its cam table

when a device sends a frame

to that port and in that frame the

source mac address will be

this guy's mac address so that makes

sense destination would be

who he's sending that frame to which

might be a person over here and you

wouldn't want to add this guy's mac

address to

this guy's port confusion it wouldn't

work if you got that right that's

amazing

you're just a little bit closer to

passing your ccna next question

which of the following addresses will a

switch use to make forwarding

decisions select the best answer

[Music]

if your answer was destination mac

address then you are absolutely

correct let's select the answer and see

if boson

thinks i'm right here is boson's

wonderful explanation i encourage you to

pause the video and read that but

looking at the question it's talking

about

a switch making forwarding decisions

well we can automatically say you know

what

source ip addresses out destination ip

address is out because again switches

don't know anything about ip addresses

now when a switch

receives a frame from a device this

frame will have a source mac

address let's just say zero zero zero

one and a destination

zero zero zero two the source is coming

from this guy

that's his mac address he's trying to

send it to the destination mac address

this guy who is probably over here and

this question explanation is perfect

because it piggybacks off the previous

question

the switch will not use a source mac

address to make forwarding decisions

however it will use it to

populate the cam table again if you got

that right congrats you are even closer

to getting your ccna and if you didn't

it's fine

go back and watch the video learning is

a process it's a day by day thing

adding to your knowledge you'll get

there trust me didn't i tell you

switches are amazing and we i know i

keep saying this

have just scratched the surface and in

this video we covered some ground on how

switches work

you even got to work in packet tracer

and watch packets and frames

go across the network you may have even

issued your first cisco

cli command which is amazing write that

down today was your first command

show mac address table you looked inside

the switch's brain inside his cam table

to see the mac address to

switch port assignment that's huge and

guys that's about it we just covered day

one switches

in the coming videos we'll be talking

about routers and we'll be talking about

the other layers

of the osi model which we kind of talked

about layers one two and three today

we'll cover the rest soon and you're

gonna love it trust me if you like this

stuff you will

love love that stuff and again huge

massive shout out to bozon software for

sponsoring

this ccna series they're making it free

so i encourage you go check them out

they have

amazing labbing software so what i

showed you today was cisco packet tracer

it's great for demonstrating to you how

a network works

boson netsim is a great lab software

that will

allow you to go through labs and once we

get deeper into like cisco command line

stuff

where it gets pretty pretty

sophisticated pretty complex

they have fantastic labs that walk you

through things they'll grade you on how

you do

and they'll even explain everything it's

it's awesome and then of course the

practice exam questions i showed you

today

that's from their practice exam and ask

around their exams are

golden if you can pass their exams uh

you can probably pass the ccna many

people say

bosons is actually harder than the real

ccna

so links below for that again they have

their summer sale it's 25

off if you have any questions or

comments please let me know below and if

you like this video

like it hit that subscribe button and

hit that bell notification

icon to be notified when i post stuff

this was ccna

day one see you on day two

[Music]

you