Cisco 802.11ac access points: Gigabit Wi-Fi threshold passed
As soon as the first wave of Gigabit Wi-Fi - 802.11ac was ratified, Cisco, as one of the participants in the development of the standard, released the first ac-access points. They are the personification of the Cisco High Density Experience: an approach to building high-speed Wi-Fi networks with high connectivity.
To get started, let's get acquainted with the main driving factors for the development of gigabit Wi-Fi. It is not always clear why to transfer data at such speeds when surfing the web, watching videos on youtube or reading posts on Facebook. It will happen at a speed of 100 Mbit / s or 500 Mbit / s - to the connected user, by and large, all the same.
The advantages of the new standard lie slightly in other planes. The first one is the density of connections to the access point. The nature of a wireless broadcast is such that only one device can transmit at a time. And if it works at low speed, then there is little time left for other devices to transfer their piece of information. As soon as we increase the client connection speed, which is allowed by the new 802.11ac standard, airtime begins to be used more efficiently. Per unit of time, more information can be transmitted, which means that more users can work on one access point. Later in the article, we will give an example when 100 clients simultaneously connected to one such access point of the Cisco 2700.
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The second important advantage is the battery life of the mobile device. It is logical to assume that if a smartphone or tablet spends less time transferring a unit of information, its battery will last longer until the next charge. This video perfectly shows that when downloading a file to a mobile smartphone via Wi-Fi, the battery charge on the 802.11ac client is exactly 2 times saved!
In May, Cisco announced a 2700 series access point with full 802.11ac support for the first wave. This means that the maximum transmission rate in a radio channel can reach 1.3 Gbit / s. The access point is equipped with three transmitting and four receiving radio elements (MIMO 3x4) and has a new distributed memory architecture.
Cisco Access Point 2700 Series
The High Density Experience approach, which involves connecting a large number of clients at high speeds, includes several mechanisms:
- New access point architecture. Unlike competitive solutions in the market, the Cisco 2700 and the older sister, the Cisco 3700, have additional memory on each radio interface. The traditional design with a single memory pool has been replaced by an improved one: at Cisco new points, each radio chip (2.4Ghz and 5Ghz) has its own buffer of 128MB. This allows you to achieve higher efficiency when aligning the order of packets from customers without overloading the CPU. The so-called TurboBoost architecture allows for better performance than the competition. This is confirmed by independent Miercom reports .
- Increased client device transfer rate using Client-Link 3.0 technology. The so-called Transmit Beamforming mechanism allows you to form a directional beam towards the client. Taking signals to different antenna elements, the access point calculates the time difference from which the signal came to each antenna. And then corrects these phase shifts when sending a signal in the direction of the client device. It is due to the fact that the signals, adding up in phase, increase the total amplitude, the transmission rate for such a client increases. The uniqueness of Client-Link 3.0 technology lies in the fact that it works for all types of clients: 802.11 a / b / g / n / ac.
- Cisco Optimized Roaming - the mechanism to disable the "stuck" customers. Clients located on the border of the access point coverage begin to transmit data at low speeds, eating airtime. All this hurts the rest of the customers and reduces their overall speed. It is Cisco roaming optimization that allows you to forcibly disable such “stuck” mobile devices, forcing them to look for a new access point or use a 3G network.
New access points have already been tested in battle. The proof that they are coping with a large number of customers and at the same time demonstrate a high average speed is a test conducted by Cisco in conjunction with the NSA Show. Without the use of special engineering firmware and specialized settings, the Cisco 2700 access point was able to demonstrate the simultaneous connection of 100 different types of clients.
Among them were both 802.11ac and 802.11n mobile devices. In this case, the total total data transfer rate was 316.9Mbit / s. This is an effective data transfer rate at the TCP / UDP level.
Source: NSA Show (http://nsashow.com/AP2700/)
Support for the standard 802.11ac, new hardware architecture and optimized roaming mechanisms allow using the new access point Cisco 2700 and its older sister Cisco 3700 to implement the High Density Experience approach, which significantly increases the number of connected clients, data transfer rate, the ability to transmit more capacious traffic. and use mobile apps.
Useful materials about:
- access point series 2700
- access point series 3700
- High Density Experience (HDX) approach
Yuri Dovgan
Cisco Systems Engineer
To get started, let's get acquainted with the main driving factors for the development of gigabit Wi-Fi. It is not always clear why to transfer data at such speeds when surfing the web, watching videos on youtube or reading posts on Facebook. It will happen at a speed of 100 Mbit / s or 500 Mbit / s - to the connected user, by and large, all the same.
The advantages of the new standard lie slightly in other planes. The first one is the density of connections to the access point. The nature of a wireless broadcast is such that only one device can transmit at a time. And if it works at low speed, then there is little time left for other devices to transfer their piece of information. As soon as we increase the client connection speed, which is allowed by the new 802.11ac standard, airtime begins to be used more efficiently. Per unit of time, more information can be transmitted, which means that more users can work on one access point. Later in the article, we will give an example when 100 clients simultaneously connected to one such access point of the Cisco 2700.
')
The second important advantage is the battery life of the mobile device. It is logical to assume that if a smartphone or tablet spends less time transferring a unit of information, its battery will last longer until the next charge. This video perfectly shows that when downloading a file to a mobile smartphone via Wi-Fi, the battery charge on the 802.11ac client is exactly 2 times saved!
In May, Cisco announced a 2700 series access point with full 802.11ac support for the first wave. This means that the maximum transmission rate in a radio channel can reach 1.3 Gbit / s. The access point is equipped with three transmitting and four receiving radio elements (MIMO 3x4) and has a new distributed memory architecture.
Cisco Access Point 2700 Series
The High Density Experience approach, which involves connecting a large number of clients at high speeds, includes several mechanisms:
- New access point architecture. Unlike competitive solutions in the market, the Cisco 2700 and the older sister, the Cisco 3700, have additional memory on each radio interface. The traditional design with a single memory pool has been replaced by an improved one: at Cisco new points, each radio chip (2.4Ghz and 5Ghz) has its own buffer of 128MB. This allows you to achieve higher efficiency when aligning the order of packets from customers without overloading the CPU. The so-called TurboBoost architecture allows for better performance than the competition. This is confirmed by independent Miercom reports .
- Increased client device transfer rate using Client-Link 3.0 technology. The so-called Transmit Beamforming mechanism allows you to form a directional beam towards the client. Taking signals to different antenna elements, the access point calculates the time difference from which the signal came to each antenna. And then corrects these phase shifts when sending a signal in the direction of the client device. It is due to the fact that the signals, adding up in phase, increase the total amplitude, the transmission rate for such a client increases. The uniqueness of Client-Link 3.0 technology lies in the fact that it works for all types of clients: 802.11 a / b / g / n / ac.
- Cisco Optimized Roaming - the mechanism to disable the "stuck" customers. Clients located on the border of the access point coverage begin to transmit data at low speeds, eating airtime. All this hurts the rest of the customers and reduces their overall speed. It is Cisco roaming optimization that allows you to forcibly disable such “stuck” mobile devices, forcing them to look for a new access point or use a 3G network.
New access points have already been tested in battle. The proof that they are coping with a large number of customers and at the same time demonstrate a high average speed is a test conducted by Cisco in conjunction with the NSA Show. Without the use of special engineering firmware and specialized settings, the Cisco 2700 access point was able to demonstrate the simultaneous connection of 100 different types of clients.
Among them were both 802.11ac and 802.11n mobile devices. In this case, the total total data transfer rate was 316.9Mbit / s. This is an effective data transfer rate at the TCP / UDP level.
Source: NSA Show (http://nsashow.com/AP2700/)
Support for the standard 802.11ac, new hardware architecture and optimized roaming mechanisms allow using the new access point Cisco 2700 and its older sister Cisco 3700 to implement the High Density Experience approach, which significantly increases the number of connected clients, data transfer rate, the ability to transmit more capacious traffic. and use mobile apps.
Useful materials about:
- access point series 2700
- access point series 3700
- High Density Experience (HDX) approach
Yuri Dovgan
Cisco Systems Engineer
Source: https://habr.com/ru/post/228587/
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