Measurement Results in Qosium

Qosium has four types of results: Average, flow, packet, and pcap results.

1. Overview #

Qosium produces various statistics that can be evaluated in real-time, e.g., with Qosium Scope. The results can also be printed into files for later analysis. During measurement, the results can be injected directly to separate results servers, such as Kaitotek’s Qosium Storage or any software that implements the QMCPQoS Measurement Control Protocol
Kaitotek’s proprietary protocol for controlling measurements and gathering measurement results. Listener interface. Further, if you have implemented the QMCP Controlling interface, you can control Qosium measurements and gather all the results directly in your software.

It is important to understand how statistics and their direction are dependent on the measurement points. The figure below opens this a bit. As seen, QoSPalvelunlaatu (Quality of Service)
Tiedonsiirtoon liittyessään palvelunlaatu kuvaa tiedonsiirtoyhteyden/verkon kykyä palvella sitä hyödyntäviä sovelluksia. and (QoEQuality of Experience
Indicates the overall performance of a network application, and how user’s experience is affected by the network conditions. statistics are always two-point statistics. Think, for example, delay/latency: network-wise, it does not exist in a single point. Instead, delay tells how long it takes for a data packet to travel from one point to another. In contrast, traffic statistics (and some general statistics and physical layer statistics as well) are calculated in single points only. Bear in mind also that sent traffic for the primary measurement point is received traffic from the perspective of the secondary measurement point.

2. Result Files #

The results file formats are the same between different Qosium components. Thus, e.g., an average results file generated by Qosium Storage can be read and analyzed using Qosium Scope. The only thing to notice is that the results files evolve with Qosium versions. This does not happen often, but sometimes. Thus, sometimes an older Qosium Scope cannot read results files generated using a newer Qosium component. In this case, please ask Kaitotek to update your Qosium.

The results files are in CSVComma-Separated Values
Originally CSV was only about values that were separated by commas, but nowadays the separation mark can also be something else like a semicolon. format, allowing easy import to external statistical tools (e.g., Excel, MATLAB, and R). Absence of a result in a file is notated as N/A.

3. Result Types #

Qosium can produce four types of results:

• Average results - Average results are averaged over Averaging Interval, which is a parameter you can define. The average results constitute the most important statistic set with over 50 specific statistics to be evaluated.
• Packet results - In a two-point measurement, Packet results give accurate QoS statistics for every single measured data packet. They are useful, e.g., in solving flickering QoS problems. In a single-point measurement, these results provide packet basic information.
• Flow results - Flow results give a straightforward view of who is communicating with who, how, and how much traffic there is flowing. Flows consuming high bandwidth are easily detected.
• Pcap results - These results provide you with full packet captures of desired traffic in the popular Pcap format, allowing you further to analyze the details with protocol analyzers such as Wireshark. This is an optional feature.

Most of the Qosium’s statistics are unidirectional, so they are available for received (downlink) and sent (uplink) directions.

4. Average Results #

4.1. General Statistics #

This category includes general measurement-level statistics that are informative rather than directly related to the networking performance.

4.2. Single-Point General Statistics #

This category includes single-point general statistics that are Probe-specific.

4.3. Physical Layer Statistics #

This category includes single-point Probe-specific statistics related to the physical layer properties, typically radio interface, including signal performance, cell information, etc. The availability of these statistics is dependent on the platform where Qosium Probe is running.

4.4. Traffic Statistics #

Traffic information that the single-point measurement can provide includes load, packet sizes, etc. These statistics are available from both primary and secondary Probe.

4.5. QoS Statistics #

QoS statistics are mostly two-point statistics that are calculated for a flow over a network path. They describe the flow’s behavior over the network path and include important statistics like delay, packet loss, etc. Some of the QoS statistics can also be calculated in a single-point measurement for a restricted set of protocols (e.g., RTP and MPEG-2 TS).

All the QoS statistics Qosium produces are one-way statistics between the measurement points.
These statistics are available in a two-point measurement only.

4.6. QoE Statistics #

This category includes higher-level statistics refined typically from the QoS statistics. The Quality of Experience (QoE) is closer to the user’s observations than the pure QoS. These statistics are available only for certain applications.

5. Packet Results #

5.1. Packet Statistics #

These are single-point statistics, giving general information on captured packets. Why not always evaluate full Pcap traces instead, since Qosium also provides them? First, taking Pcap traces from a remote point generates a control load roughly equal to the amount of measured traffic. Getting Qosium’s Packet statistics generates only a fraction of that. The same goes for the required storage space as well. Second, Qosium can be used in sensitive environments, where full packet capturing is not even allowed. In many cases, the general packet information is enough, and full captures are taken only when really needed.

5.2. Packet QoS Statistics #

In the Qosium results file, the Delivery information is coded as follows:

• 0 - The packet was delivered correctly.
• 1 - The packet was lost.
  • The packet is calculated in the Packet loss ratio statistic.
  • Reception timestamp is missing (because the packet was never received).
  • QoS values are missing.
• 2 - The packet’s sent information is not found.
  • The packet is calculated in the Sent info not found statistic.
  • The sent timestamp is missing (because the packet was never marked as sent).
  • QoS values are missing.
  • Read this for more information.

6. Flow Results #

The flow results present captured traffic as conversations between source and destination hosts. What constitutes a conversation is determined by 3 - 5 identifiers:

• Source address (and port, when available)
• Destination address (and port, when available)
• Protocol

When a packet is captured, these identifiers are compared to each existing flow’s identifiers. If none of the flows in the current flow results have the exact same identifiers, then a new flow is created instead. If no packets are detected in the given flow for the duration of the Flow timeout parameter, then Qosium determines that the flow has ended and it is removed.

7. Pcap Results #

Qosium can capture and save full packet captures as Pcap files. While Qosium itself doesn’t have a way to view these files’ contents, they can be opened with any packet analyzer tool that supports a well-known Pcap file format. For more information, see How to Take Packet Capture?.