Overview of Wireless Virtual Access Point (VAP)

Feature/Application:

This article provides an introduction to the Virtual Access Point (VAP) feature for SonicWall network security appliances equipped with internal wireless radios.

• What Is a Virtual Access Point?
• Benefits of Using Virtual APs

Overview:

What Is a Virtual Access Point?

• Virtual Access Point is a multiplexed installation of a single physical Access Point (AP) so that it presents itself as multiple discrete Access Points. To wireless LAN clients, each Virtual AP appears to be an independent physical AP, when in actuality there is only a single physical AP.
• Before the evolution of the Virtual AP feature support, wireless networks were relegated to a One-to-One relationship between physical Access Points and wireless network security characteristics, such as authentication and encryption.
• In other words, an Access Point providing WPA-PSK security could not simultaneously offer Open or WPA-EAP connectivity to clients, and if the latter were required, they would had to have been provided by a separate, distinctly configured Access Points. This forced WLAN network administrators to find a solution to scale their existing wireless LAN infrastructure to provide differentiated levels of service.
  
• With the Virtual APs (VAP) feature, multiple VAPs can exist within a single physical AP in compliance with the IEEE 802.11 standard for the Media Access Control (MAC) protocol layer that includes a unique Basic Service Set Identifier (BSSID) and Service Set Identified (SSID). This allows for segmenting wireless network services within a single radio frequency footprint of a single physical access point device.
• VAPs allow the network administrator to control wireless user access and security settings by setting up multiple custom configurations on a single physical interface. Each of these custom configurations acts as a separate (virtual) access point, can be grouped and enforced on a single internal wireless radio.

Benefits of Using Virtual APs

>> Radio Channel Conservation

• Prevents building overlapped infrastructures by allowing a single Physical Access Point to be used for multiple purposes to avoid channel collision problem.
• Channel conservation.
• Multiple providers are becoming the norm within public spaces such as airports. Within an airport, it might be necessary to support an FAA network, one or more airline networks, and perhaps one or more Wireless ISPs. However, in the US and Europe, 802.11b networks can only support three usable (non-overlapping) channels, and in France and Japan only one channel is available. Once the channels are utilized by existing APs, additional APs will interfere with each other and reduce performance. By allowing a single network to be used for multiple purposes, Virtual APs conserve channels.

>> Optimize Wireless LAN Infrastructure

• Share the same Wireless LAN infrastructure among multiple providers, rather than building an overlapping infrastructure.
• Lower down the capital expenditure for installation and maintenance of your WLANs.