Facing the Issue of VoIP Call Drops? Know The Right Treatment Options

VoIP call drops

Is your business experiencing an undesirable level of dropped calls? Dropped business calls not only create a communication halt but can also be embarrassing sometimes. If your business is experiencing frequent dropped VoIP calls, it is vital to find out the root cause and solve the issue immediately. In this blog, you will get a clear picture of the key reasons and solutions to VoIP call drops

What do you understand by dropping VoIP calls?

In today’s time, VoIP calling has emerged as a primary method of communication for several companies worldwide. The reason behind the growing usage of VoIP calling services is numerous like it is an advanced technology, cloud-based system that is highly flexible and scalable, and much more cost-effective as compared to traditional calling methods. However, there are a few shortcomings as well and one such issue with VoIP calls is the dropped calls. 

A dropped VoIP call is simply the call that disconnects from the network. When making several outbound calls on a high-volume network, one can experience the issue of dropped calls. However, the good thing is that this issue can be resolved if you are able to determine the key cause behind dropped calls. 

What makes VoIP calls to be cut off?

Dropped VoIP calls can be the result of using softphones or IP terminals with Session Initiation Protocol (SIP).  This happens because as per the SIP protocol, the phone must respond with an ACK to specify that it has received and answered the incoming call properly. This updates the call server about any in-progress communication. In case, the PBX or call server doesn’t receive such confirmation, it may result in the end of the call after a certain time. There can be several reasons why the confirmation signal sent by the SIP terminal doesn’t reach back to the PBX. However, the most common issue can be the SIP ALG. Some routers or carrier firewalls use the SIP ALG feature which is basically designed to enhance the functionality of NAT in SIP communication. In many cases, it breaks the SIP protocol, which leads to several issues like:

  • Call drops after a few seconds
  • Incoming calls that do not ring
  • One-way audio, etc. 

Other reasons for dropped VoIP calls can be: 

Call duration limit: VoIP calls can drop suddenly if a limit is placed on the call duration by the affiliated carrier or the ISP. This feature usually comes as a built-in feature to save users from huge billing charges. SO, if you are facing the issue of dropped calls, you can check the duration limit and if required, you can make the necessary changes in the call duration. 

Talk-off issue: Sometimes, the system may inappropriately identify a human voice as a DTMF tone. These are the control signals that are produced when the user presses a key on the phone keypad. When the remote server or PBX detector is triggered by human speech frequencies, it may result in a talk-off. This signal misinterpretation may lead to a call drop or call on hold. 

Connection failure: Connection failure can also be the reason for dropped VoIP calls. It can happen when:

  • There are routing issues from Internet Service Provider (ISP)
  • There is an issue in the local exchange on the receiver end

Any of these reasons can affect the system’s capacity to connect inbound phone calls. 

Breakdown of SIP Session Timer (SST): Sometimes there can be an issue with the connection cable. In such a case, the system may not send the ‘end of call’ signal immediately. However, the SIP Sessions Times (SST) stops the calls after a particular period of time. The SST system keeps on sending ‘keep alive’ messages between the endpoints at regular intervals. When the message doesn’t arrive at a particular time, the system automatically assumes that the connection has ended at the other end and it disconnects the call, resulting in a dropped VoIP call. 

Broken audio stream: If the audio stream is broken, it will lead to VoIP call audio cut in either direction. The reasons for VoIP call audio drops can be:

  • Packet loss or ISP network latency due to peak use periods
  • Bandwidth insufficiency due to a router or modem issue

How to resolve dropped VoIP calls issue?

To solve the issue of dropped VoIP calls, it is advisable to stop using the SIP ALG protocol in routers or firewalls wherever possible. Other ways to resolve dropped calls issues can be:

  • Perform speed tests using a reliable site to assure that you have enough bandwidth
  • Get an excellent quality router and set QoS.
  • Make use of advanced tools to show routes on the WAN that may be causing the issues.
  • If using VoIP networks with several locations, make sure that each location has sufficient bandwidth and is set up properly. 
  • Use SD-WAN to manage cloud service


Dropped business calls are one of the key concerns faced by several VoIP users. VoIP call drops not only affect the efficiency of business processes but may also create a bad impression about a business if this issue happens more frequently. To get rid of this embarrassing situation and to reduce this unacceptable level of dropped calls, get the required details about the nature of the dropped calls and take the help of your networking service provider to resolve the issue immediately.

Recent Posts