Dropped Calls with VoIP and How to Correct the Issue
Dropped
calls directly to a fast busy.
In this scenario an established call is made and connected, after which the call goes directly to a fast-busy signal. There is no evidence of break-up or choppiness, or fading.
Some common issues that are most likely the cause. These can be:
- If the line is an RJ11 telephone line to an ATA gateway device check that another device is not taking control of the line and subsequently ending the call or introducing a voltage. This would be more prevalent when a mix of analog and VoIP exists and older equipment is still being used, such as Caller ID devices, alarms seizing a line, etc.
- A broken wire, jack or connector.
- Multiple routers on the network that cause the call to terminate.
Dropped calls that go to dead air.
The loss of audio, especially outbound audio, can be caused by insufficient bandwidth for the RTP data. It may come back with periods of choppiness or broken voice, which is a further indication of not enough bandwidth or other applications grabbing the bandwidth. Dropped calls can also be caused by routing issues with voice data over the WAN Internet traffic on the ISP or other peering networks.
Network issues that are most likely the cause. These can be:
- Insufficient bandwidth, no QoS configured to prioritize VoIP.
- ISP and WAN router congestion and/or malfunctions. (These events are usually temporary and will clear up in a matter of hours or a day.)
- Calls to cell phones that are losing signal and disconnect. This is quite common in some cases and even when a person says that they are not talking to a cell number as they called a known office number, in many cases the calls are being forwarded onto a cell phone, which adds that next cell phone route.
- Multiple ATA devices on the same network that are signaling on the same SIP port and errantly sending a disconnect.
Correcting Dropped Calls with VoIP
- Do speed tests from a reliable site (Speedtest DSLReports) to make sure you have sufficient bandwidth and maintain that bandwidth for the calls.
- Get a better router and set QoS.
- Use tools like PingPlotter to show routes on the WAN that may be causing the issues.
- For VoIP networks with multiple locations, ensure each location has enough bandwidth and is setup properly. Use SD-WAN to manage cloud services.
Calls that do not complete or go through.
Making a call and getting a fast busy right away or an intercept message from the provider that the number does not exist (it may or may not be a valid number) or can't be made, means that the call was never established and could not be completed for one of several reasons. Always as a first step, check the number and redial.
Some common issues that are most likely the cause. These can be:
- If ongoing (not a temporary one or two time event), then most likely the issue is with the way the call is being handled by your provider or another carrier. This includes peering issues with a number from one carrier to another. These issues would require a trouble ticket to be opened with the provider.
- On International calls, especially to certain cell phones in less developed countries, the provider may not choose to route the call.
- On very busy times like holidays, the cause would most likely be capacity issues and should work at another hour in the day.