ETSI - EG 202 009-2
User Group; Quality of telecom services; Part 2: User related indicators on a service specific basis
|Publication Date:||1 December 2014|
In the current competitive world, Quality of Service (QoS) is becoming, jointly with cost, a key parameter in selling and buying telecommunications services. At the same time, technology and liberalization trends are raising new types of concerns unknown with the Plain Old Telephony Services (POTS) using switched connections provided by a single monopoly supplier.
Nowadays, there are several standards describing QoS measurements but the question of which indicators are the most interesting to be monitored from the users point of view and which values they should meet is still open. The present document proposes a reference model to evaluate the Quality of Service from the users point of view, defining the following concepts:
a) the appropriate indicators for a QoS assessment from the user point of view, i.e. KQI and SLO (see ETSI EG 202 009-1 [i.11], clause 4.3);
b) the methods to acquire the indicator values (KQI) needed to assess the quality of service.
The main principles for these definitions are:
- To define the services according to the applications performed by the user and not by the technical solution: for example, voice over IP is one of the many technical solutions to communicate between subscribers of the world-wide telephone network; ATM, frame Relay, IP are some of the many technical solutions to ensure a data transmission service between a terminal and a server or between networks. The quality criteria are the same, only the Service Level achieved can be different.
- To define the quality criteria with respect of usage and not technique. In speech quality, users are more interested in intelligibility than in bandwidth, distortion, signal to noise ratio or lost packets. Quality criteria should be defined as SLO (KQI), then translated into technical criteria (KPI). This means that providers may use different performance indicators to quantify and monitor the quality, depending on the technology used to match a particular SLO.
Therefore, the present document does not intend to describe measurement techniques since several ETSI TCs are dealing with such techniques and have the appropriate technical knowledge to develop standards in this area. ETSI EG 202 009-1 [i.11] gives guidance in identifying the indicators relevant from the user requirement point of view. If these metrics and indicators are used in a Service Level Agreements (SLA), it is crucial to define, at least for the most important ones, the agreed quality targets. If the aim is a comparison of the respective providers' performances, then quality targets can be provided as guidance for the general public to assess if the QoS of the results achieved is satisfactory or not. The preferred values and the means to aggregate them are provided in a separate document ETSI EG 202 934 [i.17].
The present document intends to define user related service specific KQI as far as possible using formal standards while ETSI EG 202 009-3 [i.12] proposes a template for a SLA dealing with all service aspects, including penalties, escalation procedures, areas of responsibility, etc. where these metrics and indicators can be used.
The purpose of the present document is to use the methodology described in ETSI EG 202 009-1 [i.11] to define, for each QoS criterion, the relevant metrics and indicators (KQI) for a choice of services and for each step of the customer relationship course. Hence each customer can have a comprehensive information on the features of the service he intends to buy according to the various providers. This will enable him to select the best suited to his needs.