Quality of Service (QoS) management is an important element of any unified communications (UC) deployment. Network engineers employ a variety of QoS methods to ensure that delay-sensitive voice and video traffic doesn’t suffer degradations while running alongside best-effort data packets. However, QoS implementation can be challenging, requiring a variety of manual interventions.
Voice quality monitoring (VQM) tools can be extremely valuable supplements to traditional QoS practices. VQM software and appliances provide detailed monitoring of traffic streams, allowing network engineers to see issues in real time through easy-to-use graphical interfaces.
Because UC traffic is generally encrypted for security and confidentiality reasons, network administrators haven’t had much visibility into this traffic. As a result, they must resort to complex and error-prone manual networking provisioning to prioritize voice traffic with path selection, bandwidth reservations and other QoS services.
For example, all voice and video packets must have appropriate header markings that identify them as high-priority network traffic — and all switches and routers along the path must be manually configured to recognize those markings. Additionally, engineers must populate network devices with tables that map these header markings to precise Class of Service (CoS) values for differentiating payloads.
However, it is difficult to extend the process beyond internal networks. Service providers generally have their own QoS requirements and don’t trust header markings coming from beyond their “trust boundaries.” Providing UC over a wireless LAN creates more complexity because WLANs require different CoS tags and traffic-prioritization standards than wired networks.
Given the complex interplay between devices across wired and wireless networks, configuration changes often have a domino effect. Any change to the network requires multiple updates to protocol-based mechanisms using device-level management tools. Changes can take days or weeks, making it difficult to maintain a consistent set of QoS settings.
Over time continual changes can cause what’s known as “configuration drift” — a state of inconsistent configuration that creates management problems and can lead to availability issues. This can make it difficult to isolate problems. Administrators must try to determine if quality issues are being caused by hardware failure, circuit issues, bandwidth restrictions or any of a number of possible glitches.
Used in conjunction with traditional QoS measures, VQM improves UC visibility and allows much faster problem resolution. These tools allow administrators to examine the full data stream and identify problem areas down to the packet level. Often, they can pinpoint the trouble and resolve it before end-users ever notice a problem.
VQM tools collect data on a variety of metrics, including jitter, delay and packet loss. They’ll also let you search and filter call records to identify calls that had connectivity issues at the beginning, dropped calls, crosstalk and other quality issues. This is not particularly new. However, older applications that gathered such data typically presented it in basic spreadsheets with little to no context. Newer products reduce the time and effort involved in reading and interpreting the data.
Troubleshooting UC issues can be a complex process. VQM tools reduces the time and effort involved in spotting and resolving problems by increasing visibility, improving understanding and speeding response time. Studies show that companies who use VQM tools also have lower operating costs than those who rely entirely upon QoS and network optimization tools.