Benefits of migrating to 802.11ac (1)

Benefits of migrating to 802.11ac (1)

In recent years, the development speed of Wireless LAN (WLAN) has greatly exceeded people's expectations, and even in stark contrast with the development of wired networks. An obvious example is that 10G Ethernet still did not become popular ten years after it passed the standard, and in 2014 there were new low-speed research groups such as 2.5G and 5G. 802.11ac (referred to as 11ac), the Gigabit wireless standard, was officially passed in December 2013. after only one year, it has become a mainstream product for various WLAN suppliers. Judging from the standard evolution trend, it also reflects the faster development of wireless technology than wired technology: the IEEE 802.3 standard has been revised for 33 times since 1983, the IEEE 802.11 standard has been revised in 31 cases since 1997.

So when we are heading for the latest 802.11ac technology products and solutions, what knowledge should we know, what experiences should we reserve, and what goals should we set to be prepared? This article will be parsed for you one by one.

Gigabit wireless: Benefits

Because 11ac's first Wave (Wave 1) speed can reach 1.3 GB, 11ac is often referred to as a gigabit wireless standard. Compared with the Wi-Fi technology standards of previous generations, the benefits brought by these standards are enormous.

Xie Qing, Cisco's senior consultant engineer, told us that the first wave of 802.11ac products has improved performance by three times compared with 802.11n (11n. 802.11ac can provide a wider channel: the first wave of 802.11ac can provide a channel width of 80 MHz (the second wave can provide 160 MHz) than the 20 hmz and 40 MHz channel widths provided by the previous standard, therefore, more bandwidth is provided. 11ac supports up to 8 spatial streams, while 802.11n supports only 4. In addition, the 11ac operates at 5 GHz, and the client is less disturbed than the 2.4GHz band used by most Wi-Fi today. "Through these enhancements, 802.11ac continues the excellent performance of 802.11n and has improved accordingly, significantly bringing faster connections to the Wi-Fi network, this gives end users a better experience." Xie Qing said.

Fu Jie, WLAN product director of Huawei switches and enterprise communication lines, further pointed out that compared with the previous generation of 802.11n products, the significant performance improvement of 11ac also comes from higher modulation efficiency, channel exclusive breaking, and link efficiency improvement. For example, the traditional 802.11n standard uses 64QAM modulation technology in the highest rate mode, and 802.11ac enables more precise 256QA modulation technology, greatly improving the modulation efficiency. For example, in the past 802.11 standard, wireless access points can only send data to one wireless terminal device at a time. When multiple terminals work, they must queue for serial occupation of empty port resources. The 802.11ac standard adopts the Innovative Technology of spatial diversity and multi-group independent beam shaping to send data to multiple terminals at the same time. When the serial channel becomes a parallel channel, the concurrency of multiple terminals is improved.

In terms of product maturity, the industry agrees that the maturity of 802.11ac Wave1 is good enough. Cisco Xie Qing gave a set of numbers like this: as of the end of 2014, nearly 1000 devices had passed the Wi-Fi Alliance's 802.11ac certification, this means that 802.11ac is much better at interoperability than 802.11n in the same period. According to reports from third-party research institutions, by the end of 2014, 50% of new factory terminal devices will adopt the 802.11ac technology, and by 2015 this proportion will reach 75%. Therefore, the deployment of 11ac products is now fully qualified.

Because the 11ac standard is divided into the first Wave (Wave1) and the Second Wave (Wave2), some users have doubts about whether to wait until the Wave 2 product comes out before deploying it. In this regard, huasan communications wireless product management department chief engineer Bai Lang said, the biggest highlight of Wave2 is the support of MU-MIMO technology, theoretically can be doubled to improve concurrency performance and access density, it is an inevitable step for 11ac to move towards more streams in the future and an important step in 11ac development. But MU-MIMO needs AP and terminal equipment at the same time to play a role, and now the market almost no support MU-MIMO terminal, according to the mature process of the industry chain, at least two years to popularize. Therefore, it is too early for most users to consider the Wave2 solution. In addition, from the perspective of enterprise-level Wave2 chip itself, it is unrealistic to realize commercial use of the true meaning in the short term.

Wu zhangming, a technical consultant for Aruba Networks Asia Pacific and Japan, believes that all customers currently know that 11ac will be fully adopted in 2015. Do you need to wait for the 11ac Wave2 product for deployment, in fact, we should check whether the standard in Wave2 is applicable to a more enterprise environment or a home user. For example, the 11ac Wave2 standard supports 4-space streaming (4 streams), but how many terminal devices support 4-space streaming? In fact, due to the limited power supply and volume, the terminal device still has a space stream antenna of less than or equal to 3. In addition, the MHz channel width is more suitable for domestic users. If the MHz plan is adopted in the enterprise environment, channel interference will be generated, and insufficient channels will cause congestion in the air. Therefore, if Wave 1 or Wave2 is used, we should first consider the deployment scenario to make a decision ."

Another important factor that makes users willing to deploy the first wave of 11ac products is that because the prices of 11ac products, especially low-end products, and 11n products are not much different, therefore, considering the fact that end users are upgrading quickly, purchasing 11ac is a cost-effective option. Because 11ac is fully backward compatible with the previous 11n and 11a/B/g products.

Most respondents believe that 11ac Wave1 and Wave2 are compatible with each other. However, Xie Qing said that the two generations of 802.11ac products are not fully compatible. users who have deployed the first generation of 802.11ac products need to replace the hardware to support the second generation of 802.11ac technology, the main reason is that the second generation of 802.11ac technology has more innovations (such as multi-user multi-input multi-output MU-MIMO, wider channel, etc.) need to be completed by the RF chip.

However, he does not think that the user needs to wait for the release of Wave2 for deployment. "Many users looking forward to 802.11ac are facing the issue of waiting for the release of the 2nd generation standard. Cisco believes that such a wait is unnecessary in most cases. If you do not deploy 802.11ac, your system capacity requirements may soon exceed the capacity that 11n can meet. 11ac Wave 2 has not yet formally defined standards, and it takes some time before its functions are widely used or interoperable ."

Users are concerned about investment protection when deploying 11ac networks. Xie Qing said that Cisco's solution is to adopt a modular, on-site upgraded 802.11ac wireless access point, such as Aironet 3700/3600. By then, "users only need to remove the currently installed Wireless Access Point and insert it into the second generation 802.11ac wireless module to achieve simple upgrade, so that the original investment will not be wasted, there is no need to change the complete hardware."

Best Selection

If 11ac technology is applied, you don't have to worry about it. Next, you need to face the following problems: how to choose the appropriate 11ac product and solution?

To this end, the reporter interviewed Shang Qun, who is responsible for network construction and O & M in the computing center of Peking University. Instructor Shang told reporters that they often consider from the following aspects when purchasing Wireless AP: "First, whether they have passed the Wi-Fi Alliance certification, certified products generally have good compatibility. 2. Whether 2G and 5G are supported at the same time. Some manufacturers cleverly use the support of '2. 4G or 5G 'to replace '2. 4G and 5G'. In this case, you need to carefully understand it. Otherwise, it may cause incompatibility with the previously deployed products. Third, the number of online clients supported at the same time ." For the third point, Mr. Shang admitted that many vendors would claim that their 11ac AP supports more than 200 terminals, but the nominal and actual number would be different. In addition, the number of clients connected to by the AP from different vendors and the number of clients that can communicate with the real environment are also different.

Shang Qun stressed that it is necessary to determine procurement indicators based on actual needs, and there is no need to pursue the highest-performance products. For example, currently, only Apple products have good support for 11ac, and 11n AP can also support 11ac terminals. Therefore, they are not prepared to use all 11ac APs. However, because the prices of 11ac AP and 11n products are not much different, some 11ac products will also be purchased for mashups. "We decided to switch from 11n to 11ac at the beginning of this year, because some clients such as Apple products are switching to 11ac. However, some 11ac clients are relatively low-end, and student applications are still dominated by 11n terminals of 2.4G 4G. Therefore, if the 11n network is good enough, the experience is fine. It is not too late to deploy a large number of 11ac APS when there are more end users using 11ac, and the price will be cheaper ." Said Shang Qun.

Shang Qun also believes that 11ac products, especially the 866M and 1.3G 11ac devices, are mature. Although the performance differences between different chips still exist, there will not be much difference in the hardware level, however, the differences in software features will be large, because the accumulation of different vendors in application scenarios is very different.