Deploying a VoIP infrastructure introduces a new set of challenges that do not exist in circuit-switched networks like the PSTN. Some of the common network problems encountered by providers deploying VoIP infrastructure include the following:
Voice Activity Detection (VAD)
1. Physical layer impairments: Noise, interference in the line, loose connectors, badly terminated punch-down block, and so on
2. Last-mile connection bandwidth: Low-speed connections, oversubscription of circuits resulting in congestion, and so on
3. Network resource overutilization: High CPU and memory utilization on network devices, oversubscription of IP links resulting in congestion, high number of input/output drops under interfaces, lack of QoS for voice, and so on
4. VoIP application issues: Poor software implementation on PC-based soft clients, lack of QoS and prioritization of resources for voice, and so on
All the above factors to be considered and verified while deploying VOIP infrastructure.
What are the common Voice Quality Problems in IP Networks?
The network problems listed above can seriously impact the quality of voice in an IP network. Some of the common voice quality issues experienced by providers include the following:
1. Noise: This is typically any noise on the line introduced by an analog source in addition to the voice signal. Noise will typically leave the conversation intelligible but still far from excellent. Static, hum, crosstalk, and intermittent popping tones are examples where the calling and called parties can understand each other, but with some effort. Some noises are so severe that the voice becomes unintelligible.
2. Voice distortion: This is typically any problem that affects the voice (RTP/media stream) itself.
3. Echoed voice: Echo voice is where the voice signal is repeated on the line. It can be heard at either end of the call, in varying degrees and with many combinations of delay and loss within the echoed signal.