When using Aircall with an SFR Box 7, call quality issues such as jitter and packet loss may occur. These issues are often linked to the SIP ALG feature, which is enabled by default on this device. Adjusting this setting can significantly improve VoIP performance.

Understanding the issue

The SFR Box 7 includes a SIP ALG feature that is activated by default. While SIP ALG is designed to help manage SIP traffic, its implementation on this device can negatively impact Aircall and other VoIP applications.

On the SFR Box 7, SIP ALG appears to:

  • Perform systematic scanning of common Voice UDP and RTP ports
  • Consume significant CPU resources on the device

This behavior can lead to degraded call quality.

Note: The issue is not caused by the SIP ALG mechanism itself. On most routers, SIP ALG works correctly with Aircall. Aircall does not use SIP TCP port 5060 or UDP port 5060.

Disable SIP ALG on SFR Box 7

To resolve call quality issues, disable the SIP ALG setting in the SFR Box 7 admin interface.

Steps:

  1. Log in to the SFR Box 7 Admin interface
  2. Locate the SIP ALG setting (refer to your device interface for exact placement)
  3. Disable the setting
  4. Save your changes

Reboot the device

After applying the change, a full restart is required.

  1. Restart the SFR Box 7 from the admin interface main page
  2. Restart your computer
Important: Always restart the SFR Box from its admin interface. This ensures that configuration changes are applied correctly and allows any pending firmware updates to be installed.

Additional recommendation

Some SFR Box models include a Filter option. If you continue to experience issues, it is recommended to turn this option off.

Tip: Disabling both SIP ALG and the Filter option can help stabilize VoIP performance when using Aircall.