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What Is SIP ALG and Why VoIP Users Should Disable It

What is SIP ALG and why VoIP users should disable it

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In this post, we discuss what SIP ALG is and how it can affect the quality of your VoIP phone calls. Disable SIP ALG to improve VoIP call quality and ensure there are fewer interruptions.

What is SIP ALG?

Session Initiation Protocol (SIP) is an internet protocol with voice data packets that initiates, maintains, and terminates voice communication between two users. SIP is used for voice calling over LTE and VoIP phone systems.

Routers used to connect to the internet also segment the provider and your internal network through Network Address Translation (NAT). This is to add an additional layer of security through a firewall allowing only authorized systems access as they connect with a network’s computers and devices.

The main purpose of SIP ALG — Application Layer Gateway — is to prevent problems caused by a router’s firewall. ALG prevents these issues by keeping an eye on the VoIP traffic (voice data packets mentioned earlier) and modifying them, when necessary. ALG works as a proxy to rewrite the destination for these packets. By doing this, ALG can improve connectivity.

Why VoIP Users Should Disable SIP ALG

Many routers have the SIP ALG feature turned on by default. With this feature on, VoIP traffic (voice data packets) can get lost due to router firewalls when transferred between the phone and the VoIP provider.

And because of this, it can lead to multiple VoIP problems, including:

  • One-way audio
  • Phones not ringing on incoming calls
  • Calls sent directly to voicemail, especially when not set to do so
  • Dropped calls, even after connecting

This is why one of the best ways to improve VoIP call quality, among others, is to disable the SIP ALG feature.

How to Disable SIP ALG in your VoIP System

Disabling SIP ALG is quick and easy, and depends on the type of modem your business uses. For most routers, you will need to:

  • Log into your router’s control panel.
  • Navigate to Advanced or Security settings.
  • Locate SIP, ALG, or Firewall settings (depends on your router’s set-up).
  • Uncheck the SIP or ALG box.
  • Save and reboot/restart your router.

If your router’s settings are not as clear, you can always reach out to your provider and ask for specific instructions.

Protect and Maintain VoIP Call Quality

Disabling SIP ALG is a common way of troubleshooting VoIP issues. However, there are other VoIP call quality issues such as jitter, packet loss, and latency that can affect the way your business communicates with its customers. Most of these issues stem from low-quality internet or insufficient bandwidth. Speak with our representatives today to learn how your internet bandwidth can affect your VoIP phone system. Call us at 1 (877) 898 8646 or chat with us online today.

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