VoIP User Complaints? - Here Are Three Hidden Causes of VoIP Quality Issues

By Special Guest
Jason Chafee, senior product manager at NetScout
  |  June 01, 2016

VoIP has seen rapid adoption in the enterprise world, particularly in the last few years. According to analyst firm Infonetics (News - Alert), VoIP and its related unified communications applications market will grow to $88 billion by 2018.

The popularity of VoIP is driven by the impressive list of benefits it offers for businesses. Not only are costs for VoIP calls much lower than traditional PBX (News - Alert) calls, VoIP offers the ability to integrate a number of useful and complementary communications applications, like video, fax, collaboration applications such as whiteboarding, and email. For companies that operate globally or with a mobile workforce, VoIP makes it easier to provide a consistent, sophisticated, and rich platform for employee communication regardless of location.

Although VoIP call quality is improving, VoIP calls don’t always deliver the quality or reliability of traditional PBX phone communications. Nearly everyone who has participated in a VoIP call has experienced at least occasional issues with dropped calls, jittery voice transmission, delays, or strange echoes. Even the biggest Star Wars fans don’t appreciate it when their boss sounds like Darth Vader on a call! While VoIP usage has slashed communications costs at companies, users still expect their calls will be as good as their consistently positive experiences with traditional PBX calls.

Always-on, high-quality communications is an essential requirement for corporate success. It’s a primary means for delivering results in customer satisfaction, achieving sales success, advancing competiveness, building corporate credibility, and maintaining reputation. When call availability is intermittent or call quality is poor, the business consequences can be huge.

Whether a VoIP system resides on an on-premises network or it’s delivered by a hosted VoIP provider, most calls will depend on several networks and devices to be completed. Many of the critical elements needed to complete a voice call are not part of a company’s IT infrastructure at all. It can be a real challenge for a network manager or technician using traditional network diagnostic tools or hosted VoIP vendor reports to troubleshoot problems when a VoIP call goes south. The VoIP network’s complexity, the requirement for visibility beyond the corporate network, and the constantly shifting dynamics of the VoIP infrastructure make it hard for IT. Still, many of the issues that have caused quality problems for VoIP networks have been well documented.

Some Common VoIP issues

Most IT managers are familiar with the typical causes of VoIP issues: insufficient network bandwidth, or lack of prioritization for voice traffic. These are relatively easy-to-identify problems and with well-understood solutions. Some of the typical quality problems created include latency, jitter, and packet loss.

Latency is the time a packet takes (in milliseconds) to leave its originating point and arrive at its ultimate destination. Latency can result in audio quality problems like echo. It can also sound as if one party is speaking before the other party is finished, a problem known as talkover. Latency is also a culprit when there are missing parts of sentences or periods of dead silence, when part of the audio drops, then resumes, if callers experience garbled audio, or other unusual sounds. Network delays – whether due to traffic, slow network links, or other causes – cause latency.

Jitter is usually noticeable as a delay in the sound during a conversation, and it can be surprisingly disruptive to the communication process. Jitter occurs when packets of voice data are received at the wrong time. It is measured by the amount of lapsed time between the delivery of consecutive voice packets. Jitter can occur due to power surges, bandwidth congestion, or other irregularities in the system.

Packet loss occurs when a network connection becomes overloaded with data or traffic, or poor quality infrastructure wiring. Packet loss results in a conversation that echoes, similar to having a conversation in a big empty room.

Here are some lesser-known causes for VoIP issues.

Mobile usage

One of the benefits of VoIP telephony is how seamlessly it enables mobile workers to connect with other employees, customers, prospects, and partners. Employees can access identical interfaces and applications from the desktop handset, computer, laptop or mobile handset, improving productivity and efficiency.

Mobility introduces unknown variables into the VoIP call-quality equation. There are a whole host of issues that can arise outside of the corporate VoIP network when an employee is using VoIP remotely.  

Wi-Fi networks are optimized for data, not voice communication. While a home or office Wi-Fi network may be entirely suitable for most data applications, voice calling is much more demanding and sensitive to timing delays caused by bandwidth constraints or cabling problems. Off-premises Wi-Fi networks may be slow and connections can be plagued by faulty or old cabling, inappropriate routers, modems, or other hardware. A faulty mobile handset or router can cause VoIP quality issues that can be difficult to diagnose. Even alarm systems, answering machines, or separate caller ID devices can cause problems for VoIP calls. 

Hotel Wi-Fi networks are another hard-to-find VoIP quality culprit for mobile users. Hotels notoriously meter out network performance for guests. This metering can play havoc with voice performance, making a user’s conversation sound as if aliens have taken control of the call. These can't be monitored or diagnosed using typical network tools alone.


Unexpected Carrier Changes

VoIP call quality issues can also be traced to unanticipated carrier service or network changes.  While most carriers are careful to specify their service parameters at the outset of a VoIP deployment, any change has the potential to disrupt the reliability and quality of the service. Such changes can be a challenge to identify.

A customer reported significant VoIP quality issues after a long period of satisfactory performance. After weeks of troubleshooting using a set of diagnostic tools for its on-premises network, the customer’s IT group realized that its carrier had changed the designation of trusted ports so critical settings were not preserved across the network. The customer had not been properly notified of the changes and had, therefore, failed to make the corresponding changes in its VoIP system. This caused employees ongoing frustration as they tried to deal with poor call quality for weeks. Using a troubleshooting capability that extended beyond the on-premises network was critical to pinpointing the cause.

Integrated Communications

VoIP could be described in some companies as a victim of its own success. Some of the very benefits that enterprises sought when they deployed VoIP can affect the quality of VoIP calls.

VoIP is attractive to businesses because they can integrate many advanced methods of communication with voice. Using a company’s existing data network for these applications saves costs. However, many of these complementary communications applications, like video and whiteboarding collaboration, are bandwidth-intensive. When extended capabilities like these are deployed by employees at a rapid or unpredicted rate, it can take up the bandwidth that previously served to support perfectly acceptable VoIP performance. Suddenly, the VoIP network that was adequate becomes under-provisioned. IT planners may not realize that additional bandwidth is required to conduct both voice communications and increased use of value-added communications. There are numerous anecdotes about network bandwidth issues that occur during popular sporting events and period of breaking news because employees are streaming video. In fact, in some cases the combination of VoIP calling and converged network communications alone could be the culprit.

No Rest for IT: Ongoing VoIP Quality Monitoring

As VoIP adoption and deployment continues to gain momentum, VoIP quality issues and the steps that can be taken to prevent problems are better understood by IT. However the dynamic, complex, and flexible nature of converged networks means that the VoIP infrastructure is never stable. It requires constant monitoring to ensure that VoIP delivers the level of quality and reliability that large multinational corporations require. Using the right tools helps IT to predict problems before users experience them and to troubleshoot issues quickly and cost-effectively. Monitoring tools that give visibility to the network inside and outside of the company’s walls can help to reduce IT head scratching when a problem appears. 

Edited by Maurice Nagle