Voice over IP (VoIP) is a fairly old technology, brought into prominence during the 90s as an alternative to the hegemony of public switched telephone network (PSTN) telephony providers in the market. While VoIP was an alternative to normal telephone at that time, it soon led to a cascade of technological developments that changed the IT landscape.

In a modern IT organization, VoIP-based technologies are indispensable. Internal company communications happen over VoIP, important meetings are held over VoIP-based video conferences, employees share their screens, hold webinars, and message each other over VoIP-based technologies. Modern unified communications platforms (UCaaS) offer VoIP and VoIP-based services in their product bundles.

VoIP is also used for external communications, either for sales and support reps to connect with clients, or between home users using popular VoIP providers like WhatsApp. It’s clear that the use of VoIP or VoIP-based technologies is widespread in both domestic and organizational settings. Now that we know just how important VoIP is, let’s go over the basics.

What is VoIP?

VoIP is simply analog voice signals traveling over IP based networks. The user’s voice is converted into IP packets which are then transported through IP-based networks like the internet. Unlike the traditional circuit switched networks which use fixed phone lines, VoIP uses the network to travel. The path isn’t always fixed and usually takes the shortest route between the source and the destination.

VoIP has several advantages over traditional telephony. VoIP is usually less expensive, more flexible, and it can integrate other features like video calling, and screen sharing. VoIP also has some disadvantages like reduced sound quality, dependence on power availability, and unpredictable quality. Nevertheless, VoIP is a mainstay in most organizations and often carries out important operations.

Why is VoIP monitoring necessary?

It’s quite clear that something like VoIP needs oversight. One of the biggest disadvantages of VoIP is the questions regarding its quality. Depending on network speed and available bandwidth, VoIP quality can drop, leading to voice distortions and failed calls. Features like voice calling, video streaming, and video calling can afford very little delay. VoIP monitoring ensures that any issues with VoIP calls are detected and alerted to the admin so service can be improved.

VoIP service providers monitor VoIP services to ensure that their service-level agreements (SLAs) are met. SLAs detail a minimum quality of service (QoS) for the VoIP service. This quality is measured using some metrics. VoIP monitoring is performed to measure these metrics.

QoS metrics for VoIP includes jitter, Mean Opinion Score (MOS), round-trip time (RTT), latency, and other performance factors. These metrics usually measure different aspects of the call. For instance, latency and RTT both refer to the delay in IP packets going between source and destination. Similarly, jitter and MOS are measures of the call quality. 

SLAs denote the maximum value a metric can have over a period of time. For instance, the jitter performance for a VoIP service taken as an average for a period of one month should not exceed one millisecond. If this term is violated, then the consumer can avail compensatory credit from the provider.

SLA terms are becoming more stringent in modern IT, and as they do, so does the cost of breaking them. This puts VoIP monitoring as vital for organizations to ensure ideal VoIP performance.

Active vs. passive VoIP monitoring

There are two ways to perform VoIP monitoring. Passive VoIP monitoring involves directly monitoring the VoIP traffic between two devices to obtain real-time metrics. Active VoIP monitoring involves creating synthetic traffic between a source and a destination to collect metrics.

Active VoIP monitoring is performed using Cisco’s IPSLA technology. Here, an IPSLA-enabled router generates VoIP traffic to a designated destination device. The destination device need not be VoIP enabled itself, but having an IPSLA-enabled destination ensures more in-depth VoIP monitoring.

Both means of VoIP monitoring have their advantages. However, active VoIP monitoring using IPSLA is more proactive compared to passive VoIP monitoring. Therefore, it is preferred. Active VoIP monitoring tools uses Cisco IPSLA to collect QoS metrics and alert IT admins when these metrics cross a preset threshold.

VoIP monitoring with OpManager

ManageEngine OpManager is a network monitoring solution that features a very strong Cisco IPSLA monitoring toolkit. Among its many capabilities, OpManager can monitor VoIP metrics, generate multiple severity alerts, and create graphs and reports using historical data to analyze VoIP performance and monitor SLA violations. Let’s see how OpManager monitors VoIP links.

Discovering VoIP links: The first step in VoIP monitoring is discovering the VoIP link. Adding a VoIP link in OpManager is easy. You can select the existing routers from your discovered inventory and enter details like source port, source interface, and destination IP address. With a VoIP link discovered, OpManager uses Cisco IPSLA to monitor VoIP status at preset intervals which can be configured by you.

VoIP monitoring snapshot: A VoIP monitoring snapshot is a repository of metrics collected from the VoIP links presented in different formats. At the top, VoIP metrics are detailed, like source-destination jitter, destination-source jitter, RTT, packet loss and latency. These values are updated with every poll so that you can view the latest status in your VoIP links. 

You can also view historical VoIP data in the graphs, charts, and bars. This includes VoIP availability, MOS history, positive and negative jitter, latency, call path availability, packet error statistics, RTT, and packet loss. Source to destination, and destination to source graphs are available for relevant metrics. Going through historical data, you can view when SLA metrics were violated, and correlate dips in the graph with other information that OpManager collects.

As mentioned earlier, being proactive is key for VoIP monitoring. You can set alerts for monitored metrics to achieve this. Upper and lower limits are specified for each monitored metric, and when the value drops out of this region, OpManager alerts you promptly. You can set thresholds and view the alerts from the snapshot page for easy accessibility. Moreover, you can set notification profiles for different alerts to be notified via email, SMS, slack, webhooks, etc.

VoIP reports: OpManager provides an arsenal of reports which can be leveraged to gain a complete overview about whatever it monitors, and VoIP is no exception. OpManager has extensive reports for each of the monitored metrics. You can view reports for different source-destination links and for different periods of time. You can export all reports to PDF or excel format.

VoIP reports in OpManager includes history reports for latency, RTT, jitter, packet loss, VoIP errors, MOS, top N call paths by jitter, packet loss, latency, etc. You can also create custom reports for specific metrics, or request new report templates in future releases.

Monitoring WAN links and video: OpManager can also use Cisco IPSLA to monitor WAN links and video streaming. Metrics like latency, packet loss, response time, and jitter are measured for these. Reporting WAN RTT is also available with OpManager.

When it comes to VoIP monitoring, ManageEngine OpManager covers all bases. This is complemented by its advanced network performance monitoring features. You can use OpManager to monitor the entirety of your network infrastructure, download OpManager or try our free 30-day trial to experience it yourself.