NXC5500/2500 Version 4.20 Edition 2, 02/2015 Application Note Smart Classroom Load Balancing Copyright 2015 ZyXEL Communications Corporation
Smart Classroom Load Balancing For wireless access service, the Smart Classroom requirements are far different from common office applications. Inter-action, real-time multimedia content access in high density environments e.g. 30~50 students simultaneously access digital education materials is a fundamental requirement in Smart Classroom scenario. ZyXEL s tailor-made Smart Classroom Load Balancing feature enables fast client load balancing between two access points deployed in one classroom, providing a reliable and non-stop wireless access service. This application note illustrates how to configure Smart Classroom Load Balancing step by step. Scenario To ensure an instant and non-stopping wireless access, two access points implementation in one smart classroom is fundamental and crucial for digital education. While students access the digital materials in class, the smart classroom load balancing feature distributes wireless traffic between 2 APs to relieve loading on the network, a fast user load balance is achieved between two access points to guarantee smooth multi-media lecturing. On the contrary, while one AP fails to serve, the other AP instantly takes over the access service and ensures a non-stop wireless access experience in smart classroom scenario. Purpose The AP would stop sending probe/association/auth response once the Max. Station Number is reached. Also, the AP would disconnect all excessive stations once by RSSI. Condition Two APs need to be in the same subnet and use same SSID, security and mode (2.4/5 GHz) to utilize the load balancing feature. 1
Benefits Fast reach of load balance Whenever there is a station that tries to associate, and if the AP is overloaded, it will check a neighbor table to see is there is a neighbor, if yes, then it will stop sending a probe/association/auth response, and disconnect over-threshold-stations every 20 sec based on the most idle/ poor RSSI status stations. Stations assigned to nearest AP All stations in the classroom are guaranteed a connection If there is no neighbor or the neighbor is aged, this AP performs as usual to accept any new station when the AP is in overloaded. 2
Topology 3
Configuration Goal: To create SSID, radio and AP group profiles for a third-grade classroom and apply the third-grade AP group profile to the two NWA5123-NI devices. 1. Create radio for 2.4 GHz band via CONFIGURATION > Object > AP Profile > Radio. 2. Create a radio profile for the 5 GHz band via CONFIGURATION > Object > AP Profile > Radio. The Channel Selection is set to Manual by default. 4
3. Create a security profile for the third-grade classroom via CONFIGURATION > Object > AP Profile > SSID > Security List. 5
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4. Create an SSID profile for the third-grade classroom via CONFIGURATION > Object > AP Profile > SSID List. 7
5. Create an AP group profile for the third-grade classroom via CONFIGURATION > Wireless > AP Management > AP Group. 5.1 Choose the configured 2.4 GHz band radio and SSID profile for the third-grade. 8
5.2 Choose the configured 5 GHz band radio and SSID profile for the third-grade. 6. Check the Enable Load Balancing box and set the Mode to By Smart Classroom. Max. Station Number is for each radio and Disassociate station when overloaded is enabled by default. 9
7. Since the available AP will be assigned to the default AP group by default, we need to move the available NWA5123-NI to the third-grade AP group as members. 10
Verification 1. Check the applied configured on the AP via MONITOR > Wireless > AP Information > AP List. 2. Check the applied configured on the AP via MONITOR > Wireless > AP Information > Radio List. 3. Check the connected stations assigned on each AP via MONITOR > Wireless > AP Information > AP List to see the Wi-Fi load balancing distributed wireless stations between the 2 APs. 11
Load Balancing Differences Station Number Traffic Level Smart Mode Mode Classroom Mode Connection Delay Delay Stop sending Assoc/Auth/Prob Assoc/Auth/Prob Assoc/Auth/Prob Kick STA Kick STA one by Kick STA one by one Kick excessive one mildly by Idle mildly by Idle STAs instantly by timeout, RSSI timeout, RSSI RSSI The disassociation is determined by the followings for Station Number mode and Traffic Level mode. Idle Timeout: STAs that have been idle the longest will be disassociated first. If no STAs are idle, the priority shifts to Signal Strength. Signal Strength: STAs with the weakest signal strength will be disassociated first. 12