Cisco Cisco Aironet 3700i Access Point 백서

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In summary, CleanAir continues to detect and report upon interference sources and AQ despite the increased

channel bandwidth. CleanAir support for monitoring the entire 80-MHz channel provides superior 802.11ac network

quality management, helps improve visibility into how the RF spectrum is being used, and enables EDRRM for the

full 80-MHz channel. Therefore, no degradation or suboptimal performance results from the migration to 802.11ac.

Features of the Cisco High Density Experience with ClientLink 3.0 Technology

Another Cisco innovation has been to create an RF solution that offers best-in-class performance to all client

devices, whether they are legacy devices (802.11g/n at 2.4 GHz and 802.11a/n at 5 GHz) or new 802.11ac-

enabled devices. Cisco ClientLink 3.0 provides optimal network performance and investment protection so that a

network administrator can confidently and effectively accommodate any device connecting to the network,

regardless of its type and capabilities.

ClientLink 3.0 is a set of RF technologies that embrace both standards-based and proprietary mechanisms for the

best possible over-the-air coverage (no dead spots) and performance (rate at range for multiple clients). ClientLink
3.0 extends Cisco’s proven and patented “client independent” proprietary signal processing techniques to include

optimal coverage and performance for 802.11ac clients, as well as for 802.11a/g/n clients. Beyond that, ClientLink

3.0 also adds support for standards-based explicit compressed beamforming (ECBF) for 802.11ac clients that are

capable of this optional feature.

Further details on ClientLink 3.0 are available in the

white paper

“Continued Industry-Leading Performance via

ClientLink 3.0 for High Density Wireless Networks.” The following section describes the highlights and significance

of ClientLink 3.0 as part of Cisco HDX.

Why ClientLink 3.0 Technology?

As three-spatial-stream 802.11ac devices come to market, and as iPads and other one- and two-spatial stream

802.11ac devices proliferate, it is critical to maximize performance for all devices. Not doing so could result in a

slower network and in slower application performance for all devices. Furthermore, legacy devices (802.11g/n at

2.4 GHz and 802.11a/n at 5 GHz) will persist. The result is a high-density environment with mixed device types and

capabilities. Therefore, ClientLink 3.0 is a key component in the High Density Experience (HDX) solution suite.

Cisc

o’s ClientLink 3.0 was designed to expand and enhance the existing ClientLink family by extending proven

transmit beamforming (TxBF) and maximal ratio combining (MRC) techniques for new features added via 802.11ac

(80-MHz channel width and 256 quadrature amplitude modulation [QAM]). This provides benefit for all 802.11ac

client devices.

Importantly, ClientLink 3.0 does not require client device involvement and therefore invokes no signaling overhead

for beamforming. Like previous generations of ClientLink, ClientLink 3.0 does not assume client participation in the

channel sounding and therefore is basically independent of device type and capabilities. In other words, the proven
“no client involvement, zero overhead” approach is applicable to, and benefits all, 802.11ac clients and continues

to be applied to all 802.11a/n clients at 5 GHz, and all 802.11g/n clients at 2.4 GHz. (That is, ClientLink and

ClientLink 2.0 methods continue to be supported in ClientLink 3.0.)

This being said, ClientLink 3.0 also adds support for standards-based ECBF for clients that implement it (ECBF is

an optional feature in 802.11ac). With ECBF the client provides estimates of the wireless channel conditions to the

access point. This can be effective but comes at the expense of overhead (airtime is consumed for the ECBF

messaging, which reduces throughput and capacity).