When data is sent across the internet, it is broken into small chunks called packets. These packets travel from one end of the connection to the other, in both directions.

When you experience high packet loss and high latency, some of these packets are not successfully reaching their destination. This can cause, or at least contribute to, increased latency and visible call quality issues.

In many cases, this is related to congestion or routing problems on the network. This article explains common causes and what to check in your environment.

How packet loss and latency are related

In typical packet loss scenarios, the most common cause is network congestion.

Modern networks are designed to manage congestion intelligently. When too much traffic builds up:

  • Some packets may be intentionally dropped to relieve congestion.

  • Not all packets are dropped, so some still arrive, but they may take longer to process.

  • These delayed packets appear as high latency.

High latency can also be caused by routing issues, where packets take an inefficient path or are lost altogether.

Software conditions

Your device operating system is the first step in each packet's journey across the internet. If the device is not operating optimally, connectivity may be affected.

Keeping your devices updated to the latest operating system helps ensure that system bugs do not cause packet loss or other network issues.

For information about device, headset and software recommendations, please visit the article Device and headset recommendations.

Hardware conditions

Faulty or low-quality hardware can also lead to packet loss.

Common areas to check:

  • Router quality: Make sure your router is reliable and in good working condition.

  • Cabling: Use short, well maintained Ethernet cables and ensure there is no visible damage.

  • Cable type: Use Cat 6 cabling where possible; Cat 5 has lower capability limits.

Restarting your router or connected device may also improve connectivity.

VPN (Virtual Private Networks)

Using a VPN increases the complexity of the network path.

This can:

  • Mislead the VoIP network about the true source location of packets

  • Lead to increased latency and packet loss, because routing may not follow a predictable or optimal path

If you are experiencing issues, consider whether a VPN is in use and, if possible, test without it.

Wifi Connectivity

If you are using WiFi, consider switching to a physically connected Ethernet connection.

WiFi is less reliable than Ethernet and may:

  • Introduce more variability in packet delivery

  • Produce inadequate call quality due to packet loss

For broader guidance on network setup and stability, please visit the article Network requirements and recommendations.

Connection Interference

Strong electrical interference can affect both physical and wireless connections.

To reduce interference:

  • Keep strongly electrical devices, such as cameras, speakers, power supplies, and phones, away from:

    • Your router

    • Network cabling

    • The device running Aircall

Use QoS when available

Some modern routers include a Quality of Service feature (QoS) feature.

QoS allows the router to:

  • Prioritize VoIP call packets over other internet traffic

  • Help ensure improved communication quality when the network is busy

Check whether your router supports QoS and enable it if present to help reduce the impact of congestion on call quality.