Cisco Cisco Aironet 3700i Access Point Libro blanco

 

 

© 2014 Cisco and/or its affiliates. All rights reserved. This document is Cisco Public Information. 

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White Paper 

Continued Industry-Leading Performance via 
ClientLink 3.0 for High Density Wireless Networks 

The Cisco

®

 Aironet

®

 3700 Series Access Point refines several innovations that result 

in industry-leading performance. This white paper explains why that matters, and how 
we do it. 

Executive Summary 

1.  The Cisco Aironet 3700 Series Access Point introduces ClientLink 3.0. 

2.  ClientLink 3.0 expands and enhances the existing ClientLink family by extending proven transmit beamforming 

(TxBF) and maximal radio 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. 

3.  At any given range, TxBF improves downstream performance and throughput to clients, while MRC improves 

upstream performance and throughput from clients. TxBF and MRC improve the overall signal quality between 

the clients and the access point: W

ith TxBF the client “hears” the access point with a better signal quality at 

range; with MRC the access point 

“hears” the client with a better signal quality at range. This improvement is 

achieved on a per-packet basis for all client device types (802.11g, 802.11a, 802.11n, and 802.11ac). 

4.  ClientLink 3.0 also adds support for standards-based Explicit Compressed Beamforming Feedback (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). 

Note: ECBF is also commonly (but incorrectly) shortened to Explicit Compressed Beam Forming). 

5.  The enhancements introduced in ClientLink 3.0 are primarily for 5 GHz, since 802.11ac is 5 GHz only. 

The proven no-client-involvement, zero-overhead approach is applicable to and benefits all 802.11ac clients. 

6.  For all 802.11a/n clients at 5 GHz, and all 802.11g/n clients at 2.4 GHz, the proven no-client-involvement, 

zero-overhead ClientLink/ClientLink 2.0 methods continue to be supported in ClientLink 3.0 and the Cisco 

Aironet 3700 Series. 

7.  ClientLink 3.0 is a key component in the High-Density Experience (HDX) solution suite. 

In summary, beamforming is most practical using techniques that don't expect assistance from the client, such as 

Cisco ClientLink 3.0 (and its predecessors). ClientLink 3.0 solves the problem of channel estimation without 

depending on client assistance and continues to add genuine value. ClientLink 3.0 still helps (1) legacy 802.11a/n 

clients, (2) those 802.11ac clients that do not support 802.11ac sounding, and (3) clients at 2.4 GHz. It also avoids 

the overhead of standards-based explicit sounding.