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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.


Capacity Test Parameters:

Capacity Speed:
Is a measure of the maximum amount of throughput data expressed in bits per second that the connection can sustain. The maximum measure will be limited to the smallest capacity of any single part of the connection’s route between the client and the LiveVox cloud.

Capacity QoS:
Is a measure of how smoothly data packets are moving. If a connection is not congested or unregulated then every packet should flow at a rate that matches the maximum capacity of the slowest part of the connection’s route. If regulation of congestion causes this pattern to change then the data flow QoS should drop. Note if there are problems affecting packets but the impact is evenly spread, e.g. all or nearly all of packets are affected then the QoS may still be high.


Speed Test Parameters:

Application Speed:
Is a measure of the actual throughput speed for a TCP (which includes HTTP) application including the impact of the connection route latency between the client and the LiveVox cloud. When the latency of a connection exceeds the data consumption time for the slowest capacity of the route (usually the clients connection) then the throughput speed will drop below the capacity

Latency:
Is a measure of the time taken for a route testing packet to reach a particular hop on the route and return . By measuring each hop along the route to the destination, including the destination it is possible to see where high latency is possible causing degradation in throughput speed or dropping packets. Latency should only be higher if there is distance involved. For example a route from London to New York will have to cross the Atlantic Ocean, 3000 miles of will obviously cause higher latency fro that hop. If you see high latency for a route validating the geography is an important step to making sense of any potential routing issues.

Round Trip Time (RTT):
Is the time it takes for a packet to be sent end-to-end between the client and the LiveVox cloud and back. The length and consistency of the trip time ultimately defines the TCP throughput speed (See Route Speed). A long trip time will dramatically slow connection throughput speed. An erratic trip time is an early indication of regulation or congestion problems.