|[Nikolay Stanchev](mailto:ns17@it-innovation.soton.ac.uk)|[University of Southampton, IT Innovation Centre](http://www.it-innovation.soton.ac.uk)|
### **Assumptions**
* Network measurement - assumption is that we have a measurement for the network link delays, called **network_delays**, providing the following information:
| path (tag) | delay | time |
| --- | --- | --- |
| path identifier | e2e delay for the given path | time of measurement |
Here, the **path** tag value is the identifier of the path between two nodes in the network topology obtained from FLIPS. The assumption is that those identifiers
will be structured in such a way that we can obtain the source and target endpoint IDs from the path identifier itself. For example:
We can easily split the string on **'---'** and, thus, find the source endpoint is **endpoint1.ms-A.ict-flame.eu**, while the target endpoint is
**endpoint2.ms-A.ict-flame.eu**.
The delay field value is the network end-to-end delay in milliseconds for the path identified in the tag value.
* A response will traverse the same network path as the request, but in reverse direction.
* Media service measurement - assumption is that we have a measurement for media services' response time, called **service_delays**, providing the following information:
| media service FQDN | ID of the service function instance | endpoint identifier | response time for the media service (s) | time of measurement |
Here, the **FQDN**, **sf_instance** and **endpoint** tag values identify a unique response time measurement. The response time field value is the
response time (measured in seconds) for the media service only, and it does not take into account any of the network measurements.
## E2E Model
Readers of this document are assumed to have at least read the [CLMC information model](clmc-information-model.md). Here we explore the requirements which inform the definition of metrics that determine *'end-to-end'* media service performance. Before continuing, some terms are defined:
...
...
@@ -104,32 +131,6 @@ understand both end-to-end and round-trip performance of a media service. This i
the data from both measurements on a given sample period, e.g. every 10 seconds. The script then posts the aggregated data back to Influx in a new measurement.
### **Assumptions**
* Network measurement - assumption is that we have a measurement for the network link delays, called **network_delays**, providing the following information:
| path (tag) | delay | time |
| --- | --- | --- |
| path identifier | e2e delay for the given path | time of measurement |
Here, the **path** tag value is the identifier of the path between two nodes in the network topology obtained from FLIPS. The assumption is that those identifiers
will be structured in such a way that we can obtain the source and target endpoint IDs from the path identifier itself. For example:
We can easily split the string on **'---'** and, thus, find the source endpoint is **endpoint1.ms-A.ict-flame.eu**, while the target endpoint is
**endpoint2.ms-A.ict-flame.eu**.
The delay field value is the network end-to-end delay in milliseconds for the path identified in the tag value.
* A response will traverse the same network path as the request, but in reverse direction.
* Media service measurement - assumption is that we have a measurement for media services' response time, called **service_delays**, providing the following information:
