The increasing effect of digital convergence and the undoubted cost and other benefits of VoIP networks has led to their widespread adoption in all sizes and types of business. However, as with all things, there are two sides to the coin, and maintenance of an acceptable level of service for your VoIP system is of paramount importance.
Before looking at monitoring techniques it is important to see what we are looking for.
Typical complaints and their cause include:
This is the common experience of a call abruptly terminating with no apparent reason. The reason is often insufficient bandwidth, incorrectly configured Quality of Service parameters, or something as simple as a defective handset.
This is one of the most common VoIP issues. The usual symptom is callers hearing their words repeated, often with a slight delay. The reason is usually that the handset volume is set too high, the microphone hears the incoming call from the earpiece and rebroadcasts it.
The obvious cure is to turn down the handset volume at one or both ends. Another resolution is to use a headset.
This often described as “breaking up”. Each caller loses whole or parts of words or sentences, often making a conversation impossible. This is caused by the network losing voice information. Voice conversations are carried in data packets, and if the connection is unstable and packets arrive in the wrong order, (“jitter”) the conversation becomes scrambled with missing information.
A common cause on office networks is insufficient bandwidth, either inherent or following use of video-conferencing or streaming video.
Delays are basically lagging in the voice information There is an excessive gap between the caller speaking and the words being heard. This can result in callers speaking over each other or interrupting each other.
Delays usually result from high latency, causing packets to take too long to reach their destination.
The key to a successful VoIP implementation is to monitor call quality to ensure an acceptable level of service to users of the VoIP system.
Here are five suggestions on how to monitor a VoIP implementation to address the issues outlined above.
Good Monitoring Software
The key phrase is “If you can’t measure it, you can’t manage it”. Addressing hearsay complaints about call quality is made much easier by using network monitoring software. There are several software applications available that run either in-house or in the cloud that can monitor the immense amount of data generated by VoIP activity in real-time and produce meaningful information about calls.
Key metrics include latency, jitter, and packet loss.
- Latency should be less than 150 milliseconds.
- Jitter is the latency of arriving packets. This must be minimised to ensure that packets arrive in the correct order.
- Packet loss. Packet loss is a specialised form of jitter, in that there must be a minimum of lost packets. If a packet is lost, the audio is recreated without the missing packets, thereby creating choppiness.
When calls are transmitted, they are compressed, digitised and made into packets. The formula used to do this is called a Codec. The wrong Codec can degrade call quality, particularly if the organisation is reaching its bandwidth limit.
If call quality is degrading, checking the Codec and if necessary choosing a more bandwidth-efficient codec can alleviate and possibly remove call quality issues.
The prudent operator will check their Internet connection equipment configuration router to ensure that VoIP traffic has priority.
Network Equipment Configuration
Networks are not static. They require monitoring and from time to time to be reconfigured particularly after equipment or software upgrades.
This consideration also applies to the overall configuration of the corporate network. It is essential to ensure that Quality of Service has been configured to prioritise VoIP, and regular monitoring of equipment upgrades and replacement to ensure that this situation is maintained is essential. Increases in complaints in a particular network segment is an indicator of misconfigured equipment.
Your Service Provider
Not all VoIP problems are internal. It is essential to monitor the performance of external service providers such as your Internet Connection provider. Once voice traffic leaves your network, you have no control over its route or if their configuration prioritises voice traffic.
You need to agree and check regularly with your service provider that VoIP traffic has priority over data traffic. This is one of the more difficult problems to resolve.