Two of the hottest networking trends in the enterprise, VOIP and WLANs, are about to collide. However, while voice/data seems like a natural, it's not quite that simple. Voice places a number of demands on WLANs that data does not, and since WLANs and the standards behind them were originally designed to be data-only networks, adding voice is not child’s play. To integrate voice effectively, you should keep these five fundamental issues in mind:
Handset Availability
Annual global sales mobile phones that can connect to a Wi-Fi network are projected to exceed 100 million by 2010. By then, you will be able to start a phone call at work, continue it in the car, and finish it up at work. All the while, your phone will detect and shift between various Wi-Fi and cellular networks. That's the vision but problems still persist. Many service providers have not invested in the Voice over WLAN (VoWLAN) because they think it threatens their traditional revenues. Other problems, like session persistence, roaming, and the need for multiple accounts for multiple networks could also slow growth.
Broadband Standards
The current choice is between 802.11b/g and 802.11a. With 802.11g you get the advantage of greater range and legacy support. 802.11a, on the other hand offers as many as 20 available channels, as opposed to the three channels offered by 802.11b/g. The choice is essentially between coverage and capacity
Quality of Broadband Service
In the data world, since applications simply reassemble the packets as they arrive, minimal packet delays don't degrade the end-user experience. Voice, on the other hand, demands a steady stream of uninterrupted packets to ensure a quality call. Even a slight interruption in the flow will degrade call quality. In WLAN traffic not only are packets delayed, they are also often lost entirely. With a voice call, the applications cannot recover when too many packets are lost, and the call is dropped.
Roaming
Poor battery life is the main reason that handset manufacturers have been slow to commit to Wi-Fi. Intra-WLAN roaming from AP (Access Point)-to-AP is responsible. Much of the battery-life problem is related to how clients roam in today's WLANs. Point to point roaming puts a heavy burden on the client, since it's up to the client to scan the network and determine where to go next, consuming a lot of power. VOW offers many advantages, but if you’re thinking of taking advantage of this powerful broadband technology, you would be wise to weigh the current risks against the potential gains before you decide to commit.
