How Can VPN Affect VoIP Calls?

Nowadays, a work from home policy is a part of the usual workflow. In companies where VoIP is a vital part of the overall performance, IT engineers might decide to route VoIP traffic across VPN along with other data. However, because VoIP quality is so sensitive to the network functionality, you need to consider the following causes that can affect your calling experience:

• Poor VPN connection
  VPN suppliers may create their networks for internet surfing (browsing information, checking emails, using applications, etc.) but not VoIP needs. Transporting voice packets is different — it requires different protocols, and the majority of VPN configurations do not work for VoIP. It is crucial to make sure that your internet speed suits basic CommPeak requirements and that VoIP packets are delivered across VPN when it is enabled in your network.
• Latency issue
  Latency is the time delay before the speaker’s voice reaches the listener’s ear over a VoIP line. Everything will be a little slower over the VPN since the connection naturally makes several hops to and from a remote location. For example, you live in London, the VPN server is in the USA, and you connect to another London-located server. Then, the packets will have to go overseas and back. Depending on the connection quality, the delay might be quite noticeable.
  According to the International Telecommunications Union, the standard for the maximum latency is 150 milliseconds (ms) per call direction and 300 ms per round trip. 300 ms is long enough, and it may be challenging to have a conversation. Thus, the shorter the transit time is — the better result you achieve. The immense distance leads to having the latency higher than the metrics above.
• Jitter
  Jitter can make a voice call hard to understand. Jitter happens when packets arrive with differing latency. It means that packets may come out of order, some may be dropped, and some parts of the voice communication may have delays when others do not. Have you ever heard the caller's voice on the other end suddenly break up and make burbling sounds? That is what jitter sounds like.

If you want to proceed with VoIP usage through VPN, you need to make sure that:

1. Internet speed inside VPN supports basic requirements for the CommPeak VoIP traffic. You may check internet speed using the CommPeak Speed Test.
2. CommPeak provides the connection between the closest point of presence (CommPeak server) and the company’s location. If the office and VPN are on different continents, this aspect will affect call quality and cause latency issues. To minimize latency, make sure that your PBX location, selected from multiple destinations worldwide, is physically close to your NAT IP geolocation.
3. The number of hops is minimized from the source IP to the destination IP to avoid latency issues.
4. You prioritize VoIP packets in your local network to get optimal call quality and decrease jitter when using VPN.
5. You configure VLAN for Softphones/WebRTC or separate voice traffic from VLAN and use LAN only to prevent packet loss issues.