VOIP – BEFORE YOU IMPLEMENT
With Voice over internet protocol becoming the preferred method of transmitting streaming conversations during a phone call, it is essential that a network be properly configured for optimum audio quality.
Prioritizing voice traffic on a network is critical to quality audio during phone calls. The network will simply try to resend data during times of network congestion when transferring or sending data. Data is usually very forgiving and will pick up where it left off when the bottleneck clears. In the case of a voice conversation, this particular strategy results in garbled conversation because of latency, delay, and jitter. The voice data packets must be reassembled on the receiving end in the order in which they were transmitted. Since data is sent over multiple channels by choosing the best route based on current network traffic, it is essential that the data packets be reassembled on the receiving end in a specific order and that they are not subject to the time delays seen during times of heavy network congestion.
This is accomplished through network prioritization. All voice traffic is given priority on the network through the use of QOS. This configuration acts in much the same way as a police officer directing traffic in a busy city. When the amount of data comes close to or exceeds the available bandwidth on a network, QOS will stop all data traffic while allowing voice traffic to continue on. In this way, you’re telling your network data packets that are designated as voice packets are always given priority for routing.
Before introducing Voice over internet protocol technology into your network, it is essential that a network assessment be completed prior to implementation. Depending on the expected call volume and the current level of utilization on the network, it might be necessary to add additional bandwidth to accommodate voice traffic. Depending on the average number of calls per day, you could see a significant demand on network bandwidth. If the amount of bandwidth is inadequate, voice quality will suffer with garbled audio and poor performance.
Although inadequate bandwidth is a common problem with Voice over internet protocol audio quality, there are other factors in the network that can affect the quality of a Voice over internet protocol call. Some networks simply have too many hops or transfers from router to router. Each of these hops can create delay because each router has to read the packet to determine its destination and then route to the next point in the route. Obviously, the greater the number of times that this occurs the greater the delay the packet will experience before reaching its destination. Whenever possible, Voice over internet protocol traffic should be routed in as direct a line as possible with a minimal number of hops. This can be accomplished by designating a VLAN or virtual local area network exclusively for Voice over internet protocol traffic. The VLAN can be configured to route voice data in a more direct line than the rest of the data being transmitted on the network.