1. What are some of the factors affecting the VoIP QoS?
To understand the concept of VoIP, this refers to phone call sessions and transmissions over the Internet.
When making a Voice over IP (VoIP) phone call, the sound of your voice is broken into thousands of packets. These packets travel through the Internet to RingCentral, and on to their final destination. Many factors can affect packets and call quality. The three (3) most common issues that affect VoIP Quality of Service (QoS) are latency, jitter, and packet loss.
Latency refers to the time it takes a voice packet to reach its destination. Latency is measured in milliseconds (ms)—thousandths of a second. Latency of 150ms is barely noticeable and generally acceptable. Latency higher than 150ms adversely affects VoIP QoS, while latency higher than 300ms is generally unacceptable.
Jitter measures the variation of packet arrival times—or simply put, how much latency varies within the network. Jitter is often caused by network congestion, timing drift, or route changes. Jitter is measured in milliseconds (ms)—thousandths of a second. Jitter greater than 50ms can increase latency and result in packet loss.
• Packet Loss (also known as data loss)
Packets are sent over the Internet and reassembled at their destination. Packet loss occurs when some packets are dropped by congested network routers or switches, or discarded by the jitter buffer. If you miss one out of every 10 words, or 10 words all at once, chances are you won’t understand the conversation.
2. What are the top issues encountered with VoIP calls?
The top issues that you may encounter with VoIP calls are the following:
3. What cause these issues?
• There might be interference from another device which might either take contol of the line where calls end abruptly. Devices known to cause interference are alarm systems, answering machines, etc.
• Specific amount of time has been set on your service which causes dropping of connection.
• If using a router, quality of connection will depend on the number of devices connected within the network. Too many devices on the network will cause a lag and will affect VoIP connectivity.
• Inadequate allocation of bandwidth and issues with RTP protocol routing, which carries the voice/audio over the line.
• Physical connection
• Static handset device
• Electromagnetic interferences such as TV, microwave or devices emitting radio frequency
4. How do I resolve these issues?
• Make sure Internet connection is stable.
• Use the recommended routers by RingCentral, proven to provide good VoIP quality. To view the list of recommended routers, click here.
• Perform a Bandwidth and QoS test. Once the results are good, open ports on the router then change the port used on the online account. Contact your account and network administrator, for further assistance.
• Verify physical connection
• For handset devices, test if the call is still static when on speaker. If it is still static, the device is for replacement should the device have been provided by RingCentral.
• If the test call is successful while on speaker, only the handset device will be replaced should the device have been provided by RingCentral.
5. What is the recommended bandwidth to support VoIP service?
A good Internet connection is needed to ensure good voice quality. It is recommended to have high-speed DSL, cable or fiber connection with an upload speed of 90 kbps or greater. Perform a Bandwidth and QoS test to determine the current download and upload speed of your Internet connection.
NOTE: If you are not getting enough speed, contact your Internet Service Provider (ISP) to improve your Internet connectivity.