Overview

Seamless wireless data and voice communication is fast becoming a reality. In fact, the technology to enable one phone number for broadband wireless data and voice communication is available now. The remaining issues facing handset designers, carriers and service providers as well as enterprise and residential network designers relate to questions of deployment, configuration and network architecture. One key capability in the next-generation wireless world will be Voice over Internet Protocol (VoIP) using 802.11 wireless local area networks (WLANs).

For wireless equipment manufacturers, service providers and enterprise/home network designers, VoIP over WLANs raises several deployment and planning issues concerning quality-of-service (QoS), call control, network capacity, provisioning, architecture and others. In addition, if the performance of each individual WLAN is to be optimized, these deployment issues must be addressed individually on a WLAN-by-WLAN basis. The requirements of the three main segments making up the WLAN marketplace also will have an effect on the deployment parameters of WLANs. These three market segments are:

• Residential/SOHO (small office, home office) cordless phones or scaled-down PBXs that will function as part of an integrated gateway
• Enterprise mobile VoIP WLAN network (private network)
• Cellular off-load network (VoIP over WLAN in hot spots, which in turn interfaces to the public telephone network)

WLAN technology and support resources are capable of providing advanced solutions tha taddress the entire market's critical requirements.

This tutorial offers an overview of VoIP over WLAN applications and explains several critical deployment issues. Crucial to the success of VoIP over WLAN applications will be the ability of WLAN technology to support and provision QoS capabilities. Further, voice services inherently involve call control signaling that requires a high level of priority in order to meet the timing constraints of interfaces to external networks, such as the wireless cellular network or the public switched telephone network (PSTN).

While deployment of the infrastructure needed for VoIP over WLAN applications will take some time to be put in place, the following diagram illustrates the goal of an IP-integrated network. Such a network would allow seamless multiple access options for most of the more prevalent voice and data services.

Figure 1.