Key Quality Considerations for VoIP Networks

Jun 28, 2020

Question: Voice over IP (VoIP) carries digital voice calls through the Internet. What are the key quality and availability issues of VoIP compared to the legacy telephony system and the probable causes?

Answer: Legacy telephone systems have their own dedicated network to operate on.

This network was “fine tuned” to for voice only and worked really well.

The problem with this 100+ year approach is it doesn’t allow nicely for other integrations to take place.

And that’s why we see other technologies like gateways which work to integrate media and other forms of communication to a legacy network.

With VoIP, that completely changes.

Early in my journey, I learned that VoIP is seen as another application on the network.

It took a while for me to really grasp this concept.

But it’s completely accurate.

Whereas voice was the only application on a legacy telephone network, VoIP is one of many applications on a IP based network.

Since IP based networks weren’t designed with voice in mind, it has to be tuned for it.

Tuning for VoIP includes:

• Prioritizing voice traffic over other using Quality of Service (QoS).

• Ensuring the network has no packet loss. Losing packets will affect the quality of voice calls and increase dissatisfaction among your customers.

• One way latency no more than 150 milliseconds (the lower the better).

• Jitter less than 30 milliseconds.

• Having enough bandwidth for voice and all other applications (voice doesn’t need a lot).

If one or more areas mentioned aren’t properly addressed, then users of a VoIP network will experience any range of audio quality problems.

From robotic voice to calls dropping completely.

There are entire books dedicated to this subject and I won’t attempt to recreate that in this answer.

But these are the key quality and availability issues with VoIP compared to legacy telephone networks.