The following definitions will help you to understand some of the technical paramaters used to measure the VoIP quality, speed and capacity of your connection.
VoIP Test Parameters:
Jitter: In an ideal world it would be nice if each packet sent took exactly the same time to travel between the client and LiveVox cloud (0% jitter) but in reality this is seldom the case and packets vary in the length of time (Latency) it takes to reach the destination which on a bad connection can be very larger. Jitter is a way to call this variance of time.
Packet Loss:Is a measure of how many packets did not reach the destination for one reason or another, expressed as a percentage of the total number of packets. Any packet loss is bad and affects the quality of applications.
Packet Loss Distribution: Is a measure of the packet loss distribution across the timeline. If a test of 1000 packets lost 1% (10 packets) then if that one packet in every 100 the distribution would be 1%. However if the loss was 10 packets in just one window of 100 packets. The loss will remain 1% (10 packets) but the distribution would be 10%. A high distribution percentage means that all the lost packets are in a small window of time causing a bigger quality problem for the application.
Mean Opinion Score (MOS): Is a measure of the quality perception of audio in a call, from 1 (being the worst) to 5 (being the best). MOS is quite subjective, as it originated from the phone companies and used human input from related quality tests. Software applications have adopted the MOS score and scale, namely 5 – Clear as if in a real face to face conversation; 4 – Fair, small interference but sound still clear. Cell phones are a good example of an everyday; 3 – Not fair, enough interference to start to annoy; 2 – Poor, very annoying and almost unusable; 1 – Not fit for purpose.
SIP ALG: ALG or Application Layer Gateway is a software component that manages specific application protocols, such as SIP (Session Initiation Protocol) and FTP (File Transfer Protocol). An ALG acts as an intermediary between the Internet and an application LiveVox cloud that can understand the application protocol. The ALG appears as an endpoint LiveVox cloud and controls whether to allow or deny traffic to the application LiveVox cloud. This is done by intercepting and analyzing the specified traffic, allocating resources, and defining dynamic policies to allow traffic to pass through the gateway.
In some the cases, ALG can be disruptive with SIP traffic as it changes the source ports after the analysis of the packets is done, so it is recommended to disable this feautre if possible.