Voice communications over wireless LAN (VoFi) is a very compelling proposition for today's enterprises. The benefits are numerous -- both from a cost point of view and from an organization point of view. However, the number of enterprises rushing to add VoFi to their networks may not be as high as some would guess.
Infonetics Research recently released the results of s survey of user organizations deploying VoIP ("User Plans for VoIP: North America 2006"), The survey indicates that only 5% of the respondents have already deployed VoIP on a wireless LAN. The total is forecast to increase to 20% by 2008. Infonetics suggests that a majority of the respondents to the survey may lack the confidence in the currently available range of offerings that support voice over wireless LAN.
VoIP on a wireless LAN does present some real technical challenges. First, there's the continuing issue of low latency/jitter/delay for a VoIP on a wireless LAN. Plus, there is the additional requirement for roaming between access points. And voice performance is the critical factor when enterprises consider deploying VoIP over a wireless LAN.
Infonetics found in its 2004 survey that 77% of the respondents rated QoS as 'very important' as a factor in evaluating whether to run VoFi. Concurrently, 71% rated IP network performance as 'very important'. In other words, voice quality must be good, but voice traffic must not degrade the network's performance.
Infonetics also found that 49% of the respondents rated VoIP management tools as 'very important.' That could be interpreted that half of the enterprises considering deploying VoIP on a wireless LAN are concerned that the management tools are not available.
There have been few tools made available specifically for VoFi testing and analysis. One of the first was VeriWave's WaveTest hardware and PC Manager software. WaveTest is capable of gathering and analyzing a wide variety of wireless LAN, and also has the ability to compute R-values.
Recently, VeriWave augmented WaveTest with VoIP QoS Service Assurance Test, a suite of tests designed to validate and ensure SLAs in high performance, VoFi networks.
'Until now, equipment manufacturers, service providers, and enterprises have not been able to verify voice traffic quality differentiation and SLAs,' said Eran Karoly, vice president of marketing for VeriWave. 'The VoIP QoS service assurance test suite lets these measurements be taken on a large scale and to enterprise standards, thus accelerating the availability of a new call of WLAN switches and Access Points'.
One of the issues that has been raised is that performance analysis of a network must not come at the cost of the actual performance of the network. Some of the available performance analysis tools have required that network encryption to be turned off when the network is being analyzed. Therefore, when troubleshooting a fault, the network is vulnerable to security threats. Even putting the security aspects aside, it can be argued that any network performance measurements or fault diagnoses that are done while traffic encryption is off will not give a true depiction of how the network really performs, because encryption, itself, can affect network performance.
Earlier last month AirMagnet shipped the first VoFi analysis instrument for encrypted networks. AT&T is one of the first customers to test AirMagnet's VoFi analyzer. AT&T's networking engineering and performance analysis lab has been using the VoFi analyzer to test its VoIP networks and to ensure the performance and security of the wireless networking technology used within its customer network designs.
'Voice-over-WLAN is a very new technology that presents its own unique set of challenges, and it's critical to be able to predict and troubleshoot issues that may arise as VoWLAN is mass deployed,' said Ron Howell, senior network architect at AT&T. 'By giving users the ability to track calls and call quality, and pinpoint the source of call issues, the AirMagnet VoFi Analyzer delivers the highest level of visibility into VoWLAN.
Now with more test tools available, the rush to add VoFi to enterprise networks will accelerate.