Performance Metrics of a VoIP Monitor
Once a Voice over Internet Protocol (VoIP) monitor is added, Site24x7 starts to collect performance metrics from both the source and the destination device to assess the quality of the calls made. You can also set thresholds for all these metrics to receive alerts when any of these limits are breached, ensuring that everything is under control during VoIP communication.
To touch up on the basics, the source is the IP address of the device that initiates the voice call, and the destination is the IP address of the device that receives the call. A call path is the WAN link between the source and destination of the VoIP call that you want to monitor.
The performance metrics are categorized as follows:
- Summary of the performance
- Destination and source metrics
- Packet error statistics
- Call path availability
Summary of the performance
| Metric | Description |
|---|---|
| Availability (%) | The percentage of time the VoIP monitor was up, running, and available over the selected time frame. |
| Mean Opinion Score (MOS) | The numerical measure of the human-judged overall quality of a call. |
| Round Trip Time (RTT) (ms) | How long it takes for a network request to go from a source to a destination and back again to the source, measured in milliseconds. |
| Jitter: Source to Destination (ms) | The variation in latency of packets carrying voice data over a call path from the source to the destination, measured in milliseconds. It is simply the inter-packet delay variance. |
| Jitter: Destination to Source (ms) | The variation in latency of packets carrying voice data over a call path from the destination back to the source, measured in milliseconds. |
| Latency: Source to Destination (ms) | Any delay in the data transfer that takes place in the communication from the source to the destination, measured in milliseconds. |
| Latency: Destination to Source (ms) | Any delay in the data transfer that takes place in the communication from the destination to the source, measured in milliseconds. |
| Packet Loss: Source to Destination (%) | The percentage of packets dropped in the call path from the source to the destination. |
| Packet Loss: Destination to Source (%) | The percentage of packets dropped in the call path from the destination to the source. |
Destination and source metrics
The following metrics are captured from the source to the destination and vice versa.
| Metric | Description |
|---|---|
| Positive Jitter (ms) | When the jitter, measured in milliseconds, is greater than the average time required to travel through the call path. |
| Negative Jitter (ms) | When the jitter, measured in milliseconds, is less than the average time required to travel through the call path. |
| Minimum Latency (ms) | The minimum delay in data transfer, measured in milliseconds. |
| Maximum Latency (ms) | The maximum delay in data transfer, measured in milliseconds. |
| Packet Loss Count | The total number of packets dropped during a call from source to destination, and destination to source. |
Packet error statistics
| Metric | Description |
|---|---|
| Delayed Packets | Packets that arrive with a delay. |
| Missing Packets | Packets that are missing in action (MIA). |
| Out-of-sequence Packets | Packets with a sequence number less than that of previously observed sequence numbers in that connection. |
Call path availability
| Metric | Description |
|---|---|
| Success (%) | The percentage of successful call paths. |
| Failure (%) | The percentage of failed call paths. |
| Busy (%) | The percentage of time when the call path was busy. |
| Errors (%) | The percentage of errors during the call path. |