VoIP & Voice Quality


http image

With VoIP today, deployment problems many times show themselves as “quality of voice” issues.    There is plenty of information on the web, including articles which offer advice on solving VoIP voice quality problems, and discuss jitter, latency and MOS scores.

Some of the ways in which we recognize voice quality problems are distorted voice, or choppy voice.  In most cases, all the words can still be understood, though you may have broken words, or dead air.  Sometimes broken words may have to be repeated.  The most severe problems are demonstrated by very distorted and choppy voice, lost sentences, extended silence, and even dropped calls.  If you are experiencing any of the problems, here is a short list of common causes:

Poor Internet Service:  VoIP is sensitive to problems in the Internet and many ISPs do not take care that they provide a reliable circuit.  These networks consist of myriad routers that connect and handoff traffic.  Each hop has some potential for creating congestion which may be fine for normal data traffic but will cause problems for VoIP, as delays tend to manifest with poor voice quality. The more circuitous the route, the greater potential for problems. Many times, you may have a faulty cable modem, possibly an outside connection that needs upgrade, an overloaded node, or other causes.   Internet service faults should be investigated for speed, ping times, packet loss, and in many cases, the network equipment (modem) needs upgrade.

Voice Priority:  Most Internet connections run over Cable today.  These connections typically offer more bandwidth from the Internet (download) than to it (upload).  Because the upload speed is smaller, voice packets usually need to be prioritized going out to the Internet.  Setting up voice prioritization for outbound calls is a great way to ensure these packets take priority over normal data transmission.  Most routers include this capability so it is recommended that it be implemented if possible. In Spectrum areas, the use of Wi-Fi over the cable modem has also been known to interfere with VoIP traffic, so it is recommended that clients use separate Wi-Fi access point(s) for wireless. Click below for our paper on common VoIP performance impacts.