User:Elisavetgrig/sandbox

Experience Level Agreement
As defined in, the “Experience Level Agreement (ELA) is a specified type of Service Level Agreement (SLA) designed to establish a common understanding of the quality levels that the customer will experience through the use of the service, in terms that are clearly understandable to the customer and to which he or she can relate.” ELAs are between providers and end-users, considering the user-centric perspective on service quality. It could be like a common SLA in terms of syntax. However, SLAs include various low-level metrics related to performance of a service, e.g., packet loss rate, throughput, bandwidth, etc. Differently, ELAs transfer the performance of a service in terms of Quality of Experience (QoE). The metrics linked with ELA could include, e.g. Mean Opinion Score (MOS) for a user perceived service. In general, ELAs and SLAs have to coexist side-by-side in an end-to-end system. ELA enables new business opportunities for the service providers because they can offer different QoE levels at convenient prices. Following this approach, some customers will to pay more for better quality. Thus, if a price differentiation like this will implement by the service provider, the user must be sure that the service worth his money.

Currently, there are two possible scenarios where ELAs are used:
 * 1) Specific service contract.
 * 2) Service-independent agreements.

ELAs and SLAs coexist at an end-to-end system. In this system, the role of SLA is to be the interface with the service and the content provider. However, the role of ELA is to be the interface with the end-users. A constrained related to ELAs is the general applicability of QoE-differentiated services. Thus, there is a need to focus on services that QoS or/and QoE measurements can be done at user`s premises at peak times for the service and translate the QoS parameters to ELA. After that, the ELA is handled via the client software used and is specific for the service. In first scenario, the case is specific for Over-The-Top (OTT) services. The transition to QoE marketization via explicit ELAs is easier in that case. In the second scenario, there are more generic arrangements that are going to be enabled at later points.

''This article was edited/created in the scope of the [QoE-NET] project, a Marie Skłodowska-Curie Initial Training Network funded by the European Commission. The changes have been co-authored or internally reviewed by senior scientists in the respective field, including [Prof.Luigi Atzori (University of Cagliari)]. In case there are questions or concerns about these edits, please leave a message with the author. Elisavetgrig (talk) 10:54, 27 January 2017 (UTC)''