All language subtitles for Free-CCNA-QoS-Part-1-Day-46-CCNA-200-301-Complete-Course_en

Welcome to Jeremy’s IT Lab. This is a free,\xa0\n

videos, please subscribe to follow along with the\xa0\n

and share the video to help spread this\xa0\n

In this video I will introduce Quality of Service,\xa0\n

of network traffic to minimize things like delay\xa0\n

4.7. However, that’s not the only thing we’ll\xa0\n

Power over Ethernet. PoE allows devices to\xa0\n

instead of requiring a separate power\xa0\n

which is a topic I didn’t mention in the\xa0\n

topics aren’t directly related to QoS, they are\xa0\n

QoS is often used to prioritize Voice over IP\xa0\n

is acceptable. So, that’s why I’ve decided to\xa0\n

They are small topics on the CCNA,\xa0\n

Here’s what we’ll cover. First up, I’ll give\xa0\n

as the concept of voice VLANs. IP phones are\xa0\n

over IP networks, such as the Internet. Then\xa0\n

which is commonly used to provide electric\xa0\n

as opposed to using a separate power\xa0\n

an intro to quality of service, QoS. I will\xa0\n

and then in the next video we’ll look at some\xa0\n

for a bonus question from Boson Software’s ExSim\xa0\n

So first let’s cover IP phones. Traditional\xa0\n

network, PSTN. Sometimes this is called POTS,\xa0\n

other hand, use VoIP, Voice over IP, technologies\xa0\n

such as the Internet. Audio data is encapsulated\xa0\n

an example of a Cisco IP phone. Cisco IP phones\xa0\n

although of course there are other vendors that\xa0\n

to a switch just like any other end host. So, you\xa0\n

at each desk, each connected to its own switch\xa0\n

but there is a much better and more common\xa0\n

IP phones have an internal 3-port switch. 1 port\xa0\n

switch. 1 port is the downlink which connects\xa0\n

the phone itself. Let me demonstrate. So, we have\xa0\n

However, within the IP phone there is a\xa0\n

One of these is used to connect to the switch\xa0\n

again with an Ethernet cable. And the last\xa0\n

This one is internal, you don’t actually have\xa0\n

So, why is this setup better? It allows the PC\xa0\n

Traffic from the PC passes through\xa0\n

Traffic from the IP phone itself\xa0\n

So, with the same amount of devices we\xa0\n

meaning we need less switches, so we don’t\xa0\n

Note that it is recommended to separate voice\xa0\n

and data traffic, which is traffic from the\xa0\n

mention this again later, but when configuring\xa0\n

the traffic from the IP phones and give it a\xa0\n

So, we can place them in separate VLANs by\xa0\n

traffic from the PC will be untagged, but traffic\xa0\n

So, how can we configure a\xa0\n

Remember, the PC and the IP phone will use\xa0\n

configure, you only need one additional command\xa0\n

Here’s the configuration. I enter interface config\xa0\n

assign it to access vlan 10, and here’s the\xa0\n

this configuration, PC1 will send its traffic\xa0\n

an access port is an ‘untagged’ port. Usually they\xa0\n

SW1 will use CDP, Cisco Discovery Protocol,\xa0\n

So, this access port is now accepting traffic\xa0\n

usually carries traffic from multiple VLANs?\xa0\n

We configured SWITCHPORT MODE ACCESS, not TRUNK.\xa0\n

I used SHOW INTERFACES G0/0 SWITCHPORT. Here we\xa0\n

voice VLAN of 11. But up here, we can see that\xa0\n

mode are static access. So, even though it\xa0\n

G0/0 is not considered a trunk port.\xa0\n

Let’s take a look at another command to\xa0\n

and nothing was displayed, telling\xa0\n

Now, even if the interface is an access port,\xa0\n

and then TRUNK. That’s what I did here.\xa0\n

again telling us that this isn’t considered\xa0\n

‘Vlans allowed on trunk’ here, but it always says\xa0\n

So, looking back a few slides, instead of\xa0\n

and each IP phone, we can take these three PCs and\xa0\n

six switchports, we are now using only three. We\xa0\n

sometimes called a data VLAN. And we configure\xa0\n

Okay, so that allows us to use fewer switchports.\xa0\n

to for an IP phone to work. Of course, being an\xa0\n

That means we need to plug them into a wall socket\xa0\n

Or, perhaps there’s a better solution that\xa0\n

And there is such a solution, it is\xa0\n

So, let’s get into PoE, Power over Ethernet.\xa0\xa0

PoE allows Power Sourcing Equipment, PSE, to\xa0\n

over an Ethernet cable. Typically the PSE is a\xa0\n

wireless access points, etc. To clarify, this is\xa0\n

data. You don’t need a separate cable. One cable\xa0\n

The PSE, the switch, receives AC power from the\xa0\n

that DC power to the PDs, for example IP phones.\xa0\n

outlet, it is the PSE, power sourcing equipment.\xa0\n

outlet provides AC power, but electronic devices\xa0\n

DC and provides it to the IP phones. These same\xa0\n

But you have to be careful about\xa0\n

Too much electrical current can harm electrical\xa0\n

a connected device needs power, and how much\xa0\n

simplification, but basically when a device is\xa0\n

sends low power signals, monitors the response,\xa0\n

These first signals are very weak to ensure\xa0\n

the connected device, causing it harm.\xa0\n

the PSE supplies power to allow the PD to boot.\xa0\n

supplying power as needed, but again not too much\xa0\n

which prevents a PD from taking too much power.\xa0\n

but let me demonstrate just a few commands\xa0\n

configured on an interface, configures\xa0\n

It will disable the port and send a Syslog\xa0\n

This is equivalent to the command POWER INLINE\xa0\n

are the default for power policing and have\xa0\n

in an ‘error-disabled’ state and then it can\xa0\n

followed by NO SHUTDOWN. Okay, so that’s one\xa0\n

POWER INLINE POLICE or POWER INLINE POLICE ACTION\xa0\n

POWER INLINE POLICE ACTION LOG does not shut down\xa0\n

It will simply restart the\xa0\n

So, because the interface\xa0\nrestarts, the connected PD\xa0\xa0

will lose power and then restart as well.\xa0\n

Let me show you those commands in\xa0\n

I issued the command POWER INLINE POLICE. Then I\xa0\n

First of all, here you can see how much\xa0\n

and how much capacity it has. But here’s what\xa0\n

specify ACTION ERR-DISABLE in the command, you\xa0\n

Okay, this time I issued the\xa0\n

ACTION LOG. I did SHOW POWER INLINE POLICE G0/0,\xa0\n

the interface won’t be err-disabled if\xa0\n

Power policing is one aspect of PoE that\xa0\n

Just be aware of its purpose, preventing PDs\xa0\n

Here are some standards of PoE. Actually, PoE\xa0\n

ILP. As has happened multiple times, for\xa0\n

the technology first for its devices, and then it\xa0\n

of power per port from the PSE, and 2 wire pairs\xa0\n

how Ethernet and FastEthernet only used 4 of the\xa0\n

They used wires 1, 2, 3, and 6. Well,\xa0\n

4, 5, 7, and 8, to provide power. Later, Cisco ILP\xa0\n

device makers would be able to use the technology.\xa0\n

provide more power than the original Cisco ILP.\xa0\n

Then, Cisco released another original\xa0\n

which stands for Universal Power over Ethernet.\xa0\n

This includes Type 3, offering up to 60 watts,\xa0\n

probably don’t have to memorize this table for the\xa0\n

what it is and what it’s used for. However, just\xa0\n

table in the supplemental resources. It’s up\xa0\n

Returning to that previous slide again, the PCs\xa0\n

get their power. But these phones are able to\xa0\n

to connect to the switch. PoE isn’t a\xa0\n

the information I gave you in this video. Now\xa0\n

Why did I spend all this time\xa0\n

in a video about QoS? It’s because the voice\xa0\n

apply QoS to, to give higher priority to the\xa0\n

First, here’s an extremely simple\xa0\n

Voice traffic and data traffic used to use\xa0\n

PSTN, public switched telephone network. And what\xa0\n

enterprise WAN or the Internet, for example a PC\xa0\n

QoS wasn’t really necessary, because the different\xa0\n

The audio quality of a phone call won’t be\xa0\n

However, modern networks are typically converged\xa0\n

regular data traffic such as web traffic, etc,\xa0\n

hasn’t disappeared, it’s still used all over the\xa0\n

now on. Converged networks enable cost savings\xa0\n

video traffic. For example IP phones can integrate\xa0\n

Microsoft Teams. However, the different kinds\xa0\n

If there is plenty of available bandwidth\xa0\n

that’s not a problem, but a busy network can\xa0\n

which is sensitive to things such as delay. QoS,\xa0\n

network devices to apply different treatment to\xa0\n

higher priority treatment, and other kinds\xa0\n

QoS is used to manage the following\xa0\n

First, bandwidth, a term\xa0\n

This refers to the overall capacity of the\xa0\n

for example kilobits per second, megabits\xa0\n

tools allow you to reserve a certain amount of a\xa0\n

For example, you could reserve 20% of\xa0\n

30% for specific kinds of important data\xa0\n

The next characteristic is delay. There\xa0\n

The amount of time it takes for traffic to go\xa0\n

delay. Let me demonstrate. The amount of time\xa0\n

is called one-way delay. Alternatively, we could\xa0\n

traffic to go from source to destination and\xa0\n

a packet to go from phone1 to phone2, but also\xa0\n

Okay, next up is Jitter. Jitter is the variation\xa0\n

same application. So, if some packets arrive in 10\xa0\n

that’s a lot of jitter, a big difference in\xa0\n

its destination. Jitter will negatively affect\xa0\n

have a jitter buffer to provide a fixed delay\xa0\n

high it will overrun the buffer and the audio\xa0\n

This refers to the percentage of packets sent that\xa0\n

by faulty cables, or if the network is congested\xa0\n

start discarding packets that can’t fit into the\xa0\n

destination, for example, that will obviously\xa0\n

There are a few recommended standards\xa0\n

Interactive audio means something like a\xa0\n

It is recommended that the one-way delay be\xa0\n

the variation in delay, should be 30 milliseconds\xa0\n

If these standards are met, you\xa0\n

but if the standards are not met there\xa0\n

quality of the phone call, the user\xa0\n

Now let me introduce the topic of queuing, which\xa0\n

QoS. If a network device receives messages faster\xa0\n

interface, the messages are placed in a queue.\xa0\n

on its G0/0 and G0/1 interfaces faster than it\xa0\n

as you can see the queue for its G0/2 interface\xa0\n

will be forwarded in a First In First Out, FIFO,\xa0\n

sent in the order they are received. No special\xa0\n

Now, what happens if the queue becomes full?\xa0\n

interfaces faster than the router\xa0\n

and the queue fills up. When this happens,\xa0\n

packet arrives and needs to be forwarded out\xa0\n

This is called tail drop, when there is not\xa0\n

Tail drop is harmful, not just because packets\xa0\n

called TCP global synchronization. To explain\xa0\n

Hosts using TCP use the ‘sliding window’ to\xa0\n

send traffic as needed. So, the host will try\xa0\n

And when a packet is dropped, it will be\xa0\n

the sender will reduce the rate it sends traffic.\xa0\n

and the process will repeat if another packet\xa0\n

drop occurs, all TCP hosts sending traffic will\xa0\n

They will all then increase the\xa0\n

which rapidly leads to more congestion, dropped\xa0\n

So, it creates waves of the network being\xa0\n

rate of transmission, and then congested, when\xa0\n

Let me illustrate it for you. Network\xa0\n

which leads to a global TCP window size decrease.\xa0\n

will decrease their window size. That leads\xa0\n

hosts reduce their transmission rate, so they’re\xa0\n

That leads to a global TCP window size increase.\xa0\n

send traffic more quickly than they currently are,\xa0\n

This leads once again to network congestion,\xa0\n

Overutilization, underutilization,\xa0\n

A solution to prevent tail drop and\xa0\n

is Random Early Detection, RED. When the amount of\xa0\n

the device will start randomly\xa0\n

Why is this better than tail drop? Those TCP flows\xa0\n

traffic is sent, but you will avoid global TCP\xa0\n

and then increase the rate of transmission at\xa0\n

the rate of traffic more even. Now, in standard\xa0\n

There is a global threshold, and if the amount\xa0\n

the device will start dropping traffic randomly as\xa0\n

Weighted Random Early Detection, WRED, allows you\xa0\n

the traffic class. So, you could for example start\xa0\n

FTP packets when the queue is that full, etc.\xa0\xa0

The kinds of traffic that you configure\xa0\n

We will cover traffic classes and more\xa0\n

the next video. For now, I think this is\xa0\n

Okay, before moving on to the quiz let’s review\xa0\n

voice VLANs. I showed you that an IP phone can\xa0\n

connected to the IP phone. A voice VLAN can be\xa0\n

will tag traffic it sends using the voice VLAN.\xa0\n

which allows end devices to receive electric\xa0\n

to send and receive data. It is commonly used for\xa0\n

Finally we got to the main topic of the\xa0\n

QoS, which allows you to give special\xa0\n

and it’s commonly used for delay-sensitive\xa0\n

However, we only covered the foundational\xa0\n

jitter, and loss. In the next video we’ll look at\xa0\n

until the end of the video for a bonus practice\xa0\n

the best practice exams for the CCNA.\xa0\n

Examine G0/0’s interface configuration. Which of\xa0\n

Okay, pause the video now to look at the\xa0\n

Okay, the answers are A, voice traffic received\xa0\n

data traffic received by G0/0 should be untagged.\xa0\n

that it is in VLAN 99, and then it should tag\xa0\n

SWITCHPORT ACCESS VLAN command on the interface,\xa0\n

Data traffic, for example sent by a PC connected\xa0\n

send its traffic untagged. After SW1 receives the\xa0\n

but when it actually receives the traffic it\xa0\n

You issue the power inline police\xa0\n

What will happen if the connected device\xa0\n

Pause the video now to think about the answer.

Okay, the answer is C, the interface will\xa0\n

be generated. To enable it again, you should\xa0\n

command on the interface. When you issue the\xa0\n

so it’s equivalent to POWER INLINE POLICE ACTION\xa0\n

Which of the following are recommended\xa0\n

audio quality? Select three. Pause the\xa0\n

Okay, the answers are B, delay of 150 milliseconds\xa0\n

and E, loss of 1% or less. If these\xa0\n

expect a noticeable reduction in the quality of\xa0\n

Which of the following is a\xa0\n

Pause the video now to think about the answer.

Okay, the answer is D, TCP global synchronization.\xa0\n

all hosts sending TCP traffic will slow down their\xa0\n

it in unison too. This leads to repeating waves\xa0\n

A TCP sliding window, is merely a mechanic in TCP,\xa0\xa0

it’s not a negative thing on its own. RED\xa0\n

so they are not a negative effect of\xa0\n

Which of the following is the default\xa0\n

Pause the video now to think about the answer.

Okay, the answer is A, FIFO, which\xa0\n

it means that packets will be forwarded\xa0\n

Higher priority packets will not be sent to\xa0\n

is something I’ll mention in the next video. RED\xa0\n

methods of forwarding queued packets, they are\xa0\n

all for the quiz. Now let’s take a look at a bonus\xa0\n

There are supplementary materials for this video.\xa0\xa0

There is a flashcard deck to\xa0\n

There will also be a packet tracer practice\xa0\n

That will be in the next video. Sign up for my\xa0\n

and I’ll send you all of the flashcards\xa0\n

Before finishing today’s video I want to\xa0\n

please click the ‘Join’ button under the video.\xa0\n

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Sorry if I pronounced your name incorrectly,\xa0\n

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