ZyXEL Communications G-3000H Manuel D’Utilisation

G-3000H User’s Guide

Chapter 7 Multiple ESS, SSID and VLAN

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This chapter describes how to use configure multiple ESS, SSID and VLAN on your ZyAIR.

See the Wizard Setup and Wireless LAN chapters for some basic WLAN scenarios and 
terminology.

Traditionally, you needed different APs to configure different ESSs. As well as the cost of 
buying extra APs, there was also the possibility of channel interference. The ZyAIR’s 
Multiple ESS (Multi-ESS) function allows multiple ESSs to be configured on just one access 
point (the ZyAIR).

Wireless stations can use different ESS IDs to associate with the same AP. Only wireless 
stations with the same ESS ID can communicate with each other. This allows the AP to 
logically group wireless stations in a manner similar to VLAN (Virtual LAN).

With Multi-ESS, the ZyAIR ignores the ToS in the header of data packets and uses a single 
QoS priority level for all of an ESS’s traffic. 

• A maximum of eight ESSs are allowed on one AP.
• Each ESS has its own MAC filter set; see the MAC filter set section for more 

information.

• When you enable Multi-ESS on the ZyAIR, you need to configure separate Unicast and 

Multicast/Broadcast keys for each ESS. A Unicast transmission is from one sender to one 
recipient. A broadcast transmission is from one sender to everybody on the network. A 
Multicast transmission is from one sender to a group of hosts on the network.

• You must use different WEP keys for different ESSs. If two stations have different ESS 

IDs (they are in different ESSs), but have the same WEP keys, they may hear each other’s 
communications (but not communicate with each other).

• When you enable Multi-ESS, ESS IDs are automatically hidden (so site survey tools 

cannot find other station ESS IDs).

• Multi-ESS should not replace but rather be used in conjunction with 802.1x security.