The term VoIP Network Assessment is often used synonomously with QoS testing and validation. When companies make the right decision to perform a VoIP Network Assessment prior to implementing an IP based telephony system like Interactive Intelligence’s CIC platform, they often assume the the assessment will focus primarily on whether or not QoS is configured properly throughout their network. While it is true that QoS plays a huge role in quality VoIP delivery, many other factors and variables come in to play and all must be properly measured and benchmarked whent a VoIP Network Assessment is performed.
Any good VoIP Network Assessment will contain metrics collected on individual paths from the host collector to an endpoint such as an IP phone. One of the metrics reported on each path is latency. Latency refers to the time in between the moment a voice packet is transmitted and the moment it reaches its final destination. Delay and echo are the result of higher latency results. When latency exceeds 150 milliseconds, voice audio quality starts to degrade.
Mean Opinion Score (MOS) is a numerical method of expressing voice quality. MOS is a representative number of the perceived quality of the media received after it has been transmitted and eventually compressed using the different codecs. Values from 4.0-4.5 are generally regarded as “toll quality”. Typically degradation can be observed in voice quality below a score of 4.0 with a 3.5 score being unusable by most user’s standards.
Bandwidth of course is the pre requisite to any VoIP deployment. Many times, customers with overly sufficient bandwidth deem QoS as not needed simply because there is no contention on the wire between the voice and data packets. We still highly recommend QoS be configured simply because data bursting and growth are often not accounted for when going the “no QoS” route.
Many VoIP Assessment service providers also don’t take into account the specifics of what type VoIP application is to be installed. Sometimes things like media server, backup voice server and media gateway placement will have a bearing on overall VoIP delivery and locations of these resources should be of note and considered when summarizing the results. Different technologies use different schemes for offloading resources from the primary voice engine as well as varied backup and disaster recovery scenarios. Knowing the difference between a media server in an Interactive Intelligence installation versus a mediation server in a Microsoft Lync environement is key to providing an accurate and all encompassing report for instance.
These are but a few of the variables besides QoS that should be considered when contemplating a VoIP Network Assessment. Engage a vendor that is experienced in recognizing the importance of all this and has the ability to test these metrics properly and you’ll guarantee yourself piece of mind that the assessment has been done properly.
For more information on VoIP Network Assessment services from Interactive Connect, email us or call (972) 562-8035 today!
