Even when call quality is generally acceptable for long periods, unexpected call disconnections may still occur on some networks and for many different reasons. In some cases, calls may be dropped because of accumulated factors that cause network congestion, an unreliable internet connection, or an unexpected interference in the call stream that the application cannot recover from.

This article explains some of the most common causes of dropped calls when using Aircall.

Upload and download restrictions

Aircall calls work similarly to any streamed content, but with a key difference in how data is sent.

When you watch a movie on Netflix or listen to music on Spotify, most of the data is sent to your device from a remote location, and very little data is sent in the opposite direction. Aircall calls are bi-directional, which means your device sends data and that it receives data in roughly equal amounts.

This bi-directional format can cause issues with typical home-based internet connections. Unlike many corporate internet tariffs, it is common for home internet connections to have much lower upload throughput compared to download throughput.

As a result:

  • Upload congestion may occur even when the internet is only being used minimally on the network.
  • If this congestion accumulates, it can lead to eventual call disconnections.

Software interruptions

Some call drops may occur due to software running on the same device.

This can happen, for example, during conflicts with resource acquisition, when two different software applications each attempt to forcibly acquire physical peripherals and device resources at the same time.

Experimenting with closing commonly open applications on the device may help improve call connection stability.

NAT and firewall settings

Routers and firewalls often come preconfigured in ways that disrupt VoIP-related traffic, which can lead to poor call quality and dropped calls.

The NAT (Network Address Translator) physically modifies the headers of VoIP packets. This can lead to problems if the NAT is configured with:

  • Port forwarding
  • SIP ALG (Application Layer Gateway)

If dropped calls occur regularly on your network, try disabling these features.

An additional issue with NATs is related to the peer-to-peer (P2P) nature of VoIP calls. Due to historically abused P2P technologies, such as torrent-based file sharing, some networks may be configured to hinder such network throughput.

This can have a relative effect on VoIP call connections. If your calls appear to disconnect after a seemingly fixed duration, this behavior may be related to how P2P traffic is being treated on the network.

Drop source

The source of a call drop is not always your own device or network. The other party on the call may also have their own connection difficulties that lead to disconnection.

At Aircall, it may be possible to detect whether the cause of the dropped call originated from your device or from the call recipient.

If call disconnections occur frequently and you would like help investigating, please contact Aircall Support so the issue can be reviewed.