Wifi 20mhz và 40mhz

Improving and managing Wi-Fi performance is important khổng lồ everyone, from trang chính users lớn large enterprises. Channel width plays a big role in Wi-Fi performance. Selecting the right width can have a huge impact. Getting it right isn't always straightforward, though. With multiple standards and a variety of tradeoffs, it can be hard lớn keep up with best practices.

Bạn đang xem: Wifi 20mhz và 40mhz

Every wireless environment is different and you need lớn tailor your equipment to lớn the conditions. With 2.4 GHz, increasing your channel width often isn't worth it, và you should stichồng with đôi mươi MHz. Conversely, with 5 GHz, increasing channel width can improve performance, but there are tradeoffs. With 5 GHz, if you don't have sầu to lớn worry about interference and all your client devices tư vấn it, go with the highest width available.

For a practical example of how lớn optimize Wi-Fi, kiểm tra out how CBT Nuggets trainer Keith Barker uses NetSpot và SweetSpots to lớn examine channels for potential interference, bản đồ his coverage, and improve his trang chính wireless network in this video:

CompTIA A+ bộ vi xử lý Core 1 (220-1001)

Related training from CBT Nuggets


Start training
*

Of course, there are plenty of "gotchas" and the rules of thumb above won't always be best for you. Like most things in tech, the right answer to this question depends on context. Let's explore the "why" behind these generalizations khổng lồ help you gain a better understanding of the topic.

Understanding Wi-Fi Bands

Understanding Wi-Fi bands is vital to lớn understanding when to lớn use trăng tròn MHz versus 40 MHz versus 80 MHz channel widths. It's also an important prerequisite to lớn understanding Wi-Fi channels & channel width.

The two main Wi-Fi bands are 2.4 GHz và 5 GHz. These Wi-Fi bands are then split inlớn channels for wireless devices to communicate on.

2.4 GHz Wi-Fi Band

The 2.4 GHz bvà covers a 100 MHz range of 2400 MHz khổng lồ 2500 MHz (equivalent to 2.4 GHz lớn 2.5 GHz). The 2.4 GHz band is split inkhổng lồ 14 discrete channels that are 20 MHz each (more on other channel sizes in a bit).

*

Source: Wikimedia

chú ý in the image above that there are 14 channels in the 2.4 GHz bvà. chú ý that channels 1, 6, 11, và 14 vày not overlap.

If you vì the math, you'll quickly see that 14 bands of đôi mươi MHz equals 180 Mhz. This is greater than the 100 MHz form size of the 2.4 GHz band, which means that channels overlap.

This is important to lớn understand because overlapping Wi-Fi channels can interfere with one another. With 2.4 GHz Wi-Fi, there are four non-overlapping trăng tròn MHz channels: 1, 6, 11, and 14. lưu ý that due khổng lồ varying regulations, not all channels are available for use in all locations. For example, only 11 channels are available in the United States.

5 GHz Wi-Fi Band

The 5 GHz Wi-Fi bvà covers a 150 MHz range from 5.725 GHz lớn 5.875 GHz. However, an additional range of Unlicensed National Information Infrastructure (UNII) bands widens that range lớn 750 MHz. Using trăng tròn MHz, there are 24 non-overlapping channels available within the 5 GHz bvà. chú ý that this is a generalization & available channels vary depending on location and channel kích cỡ.

2.4 GHz vs 5 GHz: Popularity, interference, throughput, & range

2.4 GHz is more popular than 5 GHz at the moment, but both are widely used. 2.4 GHz is cheaper lớn implement than its 5 GHz counterpart, so manufacturers leverage it to save costs. 2.4 GHz has also been widely used for a longer period of time, so more 2.4 GHz devices have sầu been deployed.

This popularity does have sầu a downside, though. The prevalence of 2.4 GHz devices & limited number of non-overlapping channels with 2.4 GHz can exacerbate network congestion issues.

Many consumer devices, such as cordless phones và microwaves, use 2.4 GHz frequency bands. As a result, 2.4 GHz bands are more likely to experience interference. The relative abundance of non-overlapping channels on 5 GHz Wi-Fi makes it less susceptible to interference.

2.4 GHz vs 5 GHz: Which khổng lồ Use?

In most cases you should use 2.4 GHz khổng lồ optimize for distance & 5 GHz to lớn optimize for tốc độ. However, there is a tradeoff between increased performance & range of coverage.

5 GHz is faster. 5 GHz Wi-Fi offers faster uploads & downloads than 2.4 GHz. Additionally, 5 GHz benefits from more non-overlapping channels and less interference which can boost performance advantages. However, 5 GHz isn't as good at going through walls.

For instance, you should use 5 GHz when for bandwidth hungry use cases like online gaming (when a wired connection isn't possible) or high-definition đoạn Clip streaming. But keep your gaming console cthua kém to lớn the router.

2.4 GHz goes further. The lower frequency of 2.4 GHz is better at passing through solid objects và can cover a wider range than 5 GHz. For a comparison across different Wi-Fi 802.11 standards, here's a breakdown of different 2.4 GHz vs 5 GHz speeds and ranges.

For instance, you should use 2.4 GHz if your Wi-Fi clients & router/access point might be separated by multiple rooms. 2.4 GHz will bởi a better job of penetrating walls và objects between your Wi-Fi devices.

You can use both. It's also worth keeping in mind that simultaneous dual b& routers can broadcast 2.4 GHz and 5 GHz at the same time. This allows you lớn use 2.4 GHz for some devices và 5 GHz for others & can provide more flexibility. Additionally, if the 2.4 GHz and 5 GHz networks use the same SSID (service mix identifier a.k.a. Wi-Fi network name), wireless devices can automatically connect to lớn their preferred bandwidth. In short: simultaneous dual band routers & modern smart devices can automatically vì chưng a lot of the work for you.

What is Wi-Fi Channel Width?

When you're making a decision aý muốn trăng tròn MHz vs 40 MHz vs 80 MHz vs 160 MHz what you're doing is picking a channel width.

We got an introduction khổng lồ Wi-Fi channels above sầu. We saw that the 2.4 GHz Wi-Fi band is chopped up inlớn smaller 20 MHz bands for use. These smaller bands are the channels that Wi-Fi devices communicate on. The channel width is simply the frequency range for the channel.

đôi mươi MHz và 40 MHz: What's the Difference?

When dealing with Wi-Fi, channel widths are usually measured in megahertz (MHz). đôi mươi MHz was the norm and only option for channel width in 802.11a and 802.11g Wi-Fi (more on the 802.11 standards below). The 802.11n standard introduced channel bonding, which enabled 40 MHz widths. 802.11ac further extended bonding to allow for 80 MHz và 160 MHz channels.

Bonding channels increases throughput, which can improve sầu performance. Thus, the difference between đôi mươi MHz and 40 MHz is throughput. 40 MHz has higher throughput than 20 MHz thanks lớn channel bonding.

There are downsides to channel bonding. While 40 Mhz might have higher throughput than 20 Mhz, it also reduces the number of non-overlapping channels. This increases the probability for interference. Additionally, not all Wi-Fi client devices tư vấn channels other than 20 MHz so compatibility can be a concern.

A note on marketing lingo và tech talk: trăng tròn MHz Wi-Fi channels are generally referred to as "narrow channels" or "narrow widths". 40, 80, và 160 MHz Wi-Fi channels are labeled "wide channels" or "wide widths"

Understanding IEEE 802.11 Standards

If you are exploring router specs, studying for a Network+, or trying to lớn determine Wi-Fi compatibility, 802.11 has likely come up. IEEE develops the 802.11 Wi-Fi standards, and these standards dictate what speeds & frequencies are supported.

Here is a quichồng rundown on the well-known IEEE 802.11 standards:

802.11a was an early 5 GHz 54 Mbps Wi-Fi standard.802.11b was a popular early 2.4 GHz 11 Mbps version of Wi-Fi.802.11g increased 2.4 GHz Wi-Fi speeds up to lớn 54 Mbps.802.11n a.k.a. "Wi-Fi 4"supports both 2.4 GHz và 5 GHz Wi-Fi at speeds up khổng lồ 450 Mbps.802.11ac a.k.a. "Wi-Fi 5" supports 5 GHz only and speeds of up lớn 1300 Mbps.

802.11n and 802.11ac tkết thúc to be the most popular standards available today. You can expect 802.11ax khổng lồ grow in popularity over the next few years.

It is important to note that maximum theoretical speeds are NOT the same as real-world speeds.

Xem thêm: Game Age Of Empires Iii: Complete Collection Free Download &Raquo; Steamunlocked

In other words: With any given Wi-Fi version, you can expect slower actual speeds than the max speeds listed here.

What about 6 GHz & Wi-Fi 6E?

In April of 20đôi mươi, the FCC announced they will open up the 6 GHz bvà for Wi-Fi & other unlicensed use. The additional 1,200 MHz is the biggest addition of usable spectrum in decades. Wi-Fi 6 devices capable of using the 6 GHz bands will be known as "Wi-Fi 6E". The "E" signifies the extension into the 6GHz specturm.

Wi-Fi 6E devices aren't readily available today, but you can expect khổng lồ see them on the market in late 20đôi mươi and early 2021.

In short: Wi-Fi 6E will enable some big improvements, but it'll be some time before it becomes the norm.

What's Dual Bvà Wi-Fi?

Dual band refers to lớn Wi-Fi routers that support both 2.4 GHz & 5 GHz bands. Using a dual bvà router allows you to lớn get the "best of both worlds". Higher speeds và lower interference for 5 GHz devices, & wider range for 2.4 GHz devices. It is very common for modern Wi-Fi routers khổng lồ tư vấn dual b& functionality.

When to Use 20 MHz vs 40 MHz vs 80 MHz?

With an understanding of Wi-Fi frequencies và channel bonding, we can now dive sầu inlớn the decision making process. As we go, remember that a prerequisite for using any particular channel width is device support.

2.4 Ghz WiFi: 20 MHz vs 40 MHz vs 80 MHz

If you're using 2.4 GHz, the answer is simple. The best bandwidth for 2.4 Ghz is trăng tròn MHz.

In the majority of cases, using wide widths on 2.4 GHz isn't worthwhile.

The performance tradeoffs from interference on overlapping channels will likely outweigh the throughput benefits. One possible exception lớn this rule is remote areas where there are not many other Wi-Fi networks or devices.

Additionally, 2.4 GHz Wi-Fi & 20 MHz channel widths offers the broadest range of client device support. If you need to tư vấn legacy devices and Wi-Fi standards lượt thích 802.11b or 802.11g, you'll need 2.4 GHz and đôi mươi MHz.

5 Ghz Wi-Fi: 20 MHz vs 40 MHz vs 80 MHz

With 5 GHZ, things get a bit less straightforward. There are valid use cases for multiple different Wi-Fi channel widths. The best bandwidth for 5 Ghz is 40 MHz. However, there are other considerations as well.

5 Ghz Wi-Fi: When to lớn Use 20 MHz

If you have sầu a 5 GHz router, consider using đôi mươi MHz for maximizing the amount of non-overlapping channels. Regardless of using 2.4 GHz or 5 GHz, 20 MHz leaves you with the largest amount of non-overlapping channels. trăng tròn MHz makes sense for high-density deployments & areas where interference is a major problem.

5 Ghz Wi-Fi: When to lớn Use 40 MHz

Use 40 MHz khổng lồ strike a balance between minimizing interference và maximizing throughput.

40 MHz offers more throughput than đôi mươi MHz. It still leaves room for a dozen or so non-overlapping channels. This enables you lớn improve sầu performance relative lớn đôi mươi MHz, & without risking the interference associated with 80 MHz.

5 Ghz Wi-Fi: When to lớn Use 80 MHz

If Wi-Fi clients are close to your router, your Wi-Fi devices tư vấn 80 MHz, interference isn't a big issue, & you want khổng lồ maximize throughput, consider 80 MHz.

If all your devices support it, & overlapping channels is not an issue, 80 MHz channels leave sầu you with four or five sầu non-overlapping channels. This increases the likelihood for interference. Additionally, clients often need to lớn be very cđại bại ( it just isn't that simple.

Interference from overlapping channels can wreak havoc on network speeds, so you must trương mục for it. This is particularly important in cities, industrial areas, and large businesses where high levels of wireless traffic are common.

When to lớn Use 160 MHz

At this point, the use cases for 160 MHz are limited. However, as 802.11ax (Wi-Fi 6) grows in popularity, we can expect khổng lồ see use of 160 MHz widths grow as well. With 160 MHz, there is only one available non-overlapping channel, so there will be interference tradeoffs lớn consider with 160 MHz.

Of course, the 6GHz b& and Wi-Fi 6E will change this narrative sầu in the near future. The additional spectrum in the 6 GHz bvà will allow for 14 more 80 MHz channels or 7 more 160 MHz channels.

How lớn Automate Wi-Fi Channel & Width Selection

As you can see, there's quite a bit khổng lồ selecting Wi-FI channel và width selection. However, there are ways khổng lồ automate the process.

For example, some Wi-Fi routers enable automatic detection and use of a channel kích cỡ based on network conditions. This is usually achieved by selecting "Aukhổng lồ 20/40" or similar option as your channel width. Similarly, with most routers và devices, channel selection can be negotiated automatically. If you're not experiencing issues, & aren't looking to lớn optimize performance, sticking with these settings makes sense.

How Can I Cheông chồng for Wi-Fi Interference?

If you are looking lớn optimize performance, a Wi-Fi network analyzer may help. Wireless network analyzers can help you identify interference on different channels & select the least noisy option. Alternatively, manually switching between channels & observing performance is a less scientific alternative.

Selecting the Right Wi-Fi Channel

When it comes lớn selecting the right Wi-Fi channel width, every situation is different. By understanding the fundamentals, you can more effectively select a configuration that works best for you. While there is no one-size-fits all answer to lớn the "đôi mươi MHz, 40 MHz, or 80 MHz?" question. However, understanding 2.4 GHz vs 5 GHz frequencies và the tradeoffs between non-overlapping channels và tốc độ goes a long way.

*

Download

Ultimate Networking Cert Guide

A 97-page guide khổng lồ every Cisco, Juniper, F5, và NetApp certification, and how they fit inkhổng lồ your career.

First NameRequiredLast NameEmailWhat is your job role?Select...I'm an IT pro looking to lớn sharpen my skills or earn a certificationI lead an IT team và am looking for training solutionsI'm not an IT pro, but interested in entering the fieldOtherI'd like to receive sầu CBT Nuggets IT training news và resourcesSubmit

I have read and understood the privacy policy, & am able to consent to it.

Not a CBT Nuggets subscriber? Start your không tính phí week now.

Xem thêm: Khuôn Silicon Có Độc Không ? Keo Silicon Dẻo Dán Tường Có Độc Không

CBT Nuggets has everything you need lớn learn new IT skills and advance your career -- unlimited Clip training and Practice Exams, Virtual Labs, validated learning with in-Clip Quizzes, Accountability Coaching, và access lớn our exclusive community of IT professionals.