ZyXEL Communications NWA-3163 & NWA-3166 User Manual

Chapter 21 Load Balancing

NWA-3160 Series User’s Guide

Imagine a coffee shop in a crowded business district that offers free wireless 
connectivity to its customers. The coffee shop owner can’t possibly know how 
many connections his NWA will have at any given moment. As such, he decides to 
put a limit on the bandwidth that is available to his customers but not on the 
actual number of connections he allows. This means anyone can connect to his 
wireless network as long as the NWA has the bandwidth to spare. If too many 
people connect and the NWA hits its bandwidth cap then all new connections must 
basically wait for their turn or get shunted to the nearest identical AP.

The following figure depicts an NWA with a hard bandwidth limit of 6 Megabits per 
second (Mbps). Bandwidth up to 6 Mbps is considered “balanced”. More than that 
and it becomes “overloaded”; the AP must then work harder to serve each client.

Figure 162   Load Balancing by Traffic Level Example

The yellow (Y), green (G) and blue (B) laptops are each using approximately 2 
Mbps. Altogether, they consume the AP’s entire “balanced” bandwidth allotment. 
When the red (R) laptop tries to make a connection, the AP (which does not want 
to overload itself) denies it if an identical AP is in range that can take on the 
burden of the new connection.

Note: If no other APs with matching settings are in range of the NWA, then it will still 

accept the connection despite becoming overloaded.