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Smart Client Load Balancing

by Robert Ferruolo (Dr. RF) on Aug 16, 2016
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Wireless Is Great, Except When It Isn’t

One of the challenges of WiFi is that clients are notoriously self-interested and use a very rudimentary decision-making process to determine which access point to connect to. This decision is simply based on AP signal strength or signal-to-noise ratio (SNR). The IEEE 802.11k standard is designed to help the clients make better, more informed roaming decisions, but to date very few clients have implemented it.

Since the clients are currently lacking, it falls to the WLAN system to persuade clients to perform better. Enterprise class WiFi APs gather and share information that can help automatically tune and optimize the environment to provide a better overall user experience. One of the tools included in the 8.1 release of Mojo Wireless Manager that can improve overall user experience is Smart Client Load Balancing.

The Closest AP Isn’t Necessarily the Best AP

If left to their own devices, WiFi clients connect to the closest AP, which can cause problems. Imagine 30 clients close to a single AP, in a classroom or in a meeting room. Most of WiFi devices will connect to that one AP, even though there are other APs nearby with good signal strength. There are two inefficiencies that result:

  1. Resource Sharing – When 30 clients are on a single AP, the AP’s resources are divided 30 ways, and not always evenly. Overall it would be better if the clients were distributed over the three neighboring APs, even though 20 clients will connect to APs with lower signal strengths.
  2. Contention Loss – There is no coordination between devices, so when 31 devices (30 clients and one AP) are transmitting at the same time, there will be collisions. This contention penalty increases and compounds with the number of devices.
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Clients per AP Clients Choose Load Balanced
AP 1 30 10
AP 2 0 10
AP 3 0 10

 

How Smart Client Load Balancing Helps

Smart client load balancing distributes the client load between neighboring APs, improving overall operational efficiency. Overall and individual client throughput increases when the 30 clients are evenly distributed, even when some of the clients connect at a lower data rate (signal strength), because there is much less contention, and each client gets a larger share of its AP’s time.

For more information and directions on how to load balance your clients, read the Smart Client Load Balancing application note in the Mojo Support portal. Or click below to read about Mojo Wireless Manager, which controls load balancing.

Check out Mojo Wireless Manager

Topics: Mojo Wireless Manager, Smart client load balancing, WLAN