Cisco Cisco Aironet 1140 Access Point 백서

White Paper

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Use of ClientLink does not result in any changes to the output power of the access point. In general, it is not a

good idea to increase output power either due to FCC limits, or due to issues with co-channel interference on

neighboring cells. Although it might seem possible to decrease output power because of improved SNR at

the clients, this would reduce the range of broadcast packets, which do not experience the gain.

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In addition to providing gain in an indoor multipath environment, ClientLink also provides increased SNR at

the client in line-of-sight environments such as outdoors or large open indoor spaces.

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ClientLink interoperates seamlessly in mixed mode environments where 802.11n and 802.11a/g clients co-

exist on the same access point. For 802.11a/g clients, transmit beam forming is used to increase the gain

towards the client. For 802.11n clients, spatial multiplexing is used to deliver enhanced high throughput data

rates upwards of 300 Mbps. In this manner the optimum MIMO technology is dynamically selected to deliver

benefits to each client type.

Summary

In the next few years, it will be common for Wi-Fi networks to support a mix of 802.11a/g and 802.11n clients. Cisco

ClientLink technology helps solve the problems of mixed-client networks by making sure that older 802.11a/g clients

operate at the best possible rates, especially when they are near cell boundaries. Unlike most 802.11n access

points, which only improve the uplink performance, Cisco ClientLink technology improves performance on both the

uplink and downlink providing a better user experience during web browsing, email, and file downloads. Similarly, the

improved robustness of the link benefits connectivity-oriented applications such as voice and SAP database on

handheld appliances. Finally, ClientLink technology is based on signal processing enhancements to the access point

chipset and does not require changes to network parameters. The Cisco M-Drive solution and Cisco ClientLink

technology help solve one of the key challenges associated with 802.11n adoption. It extends the useful life of

existing 802.11a/g devices and is beneficial for organizations that want to ensure that all clients on the network,

regardless of type, are guaranteed the bandwidth and throughput they need.

Printed in USA

C11-516389-02 05/09