3.3 Quality of Services (QoS) [1]¶
Quality of Services (QoS) refers to the API non-functional description, or the ability of the latter to meet the expectations of users.
Ensuring QoS on the Internet for interoperability purposes is a critical challenge due to the dynamic and constantly evolving nature of the technological environment. Changes in traffic patterns, the presence of critical transactions, the effects of network problems, the performance of network protocols and standards require an accurate and precise definition of the QoS offered by an API.
The key elements supporting QoS can be summarized as follows:
| Availability | The likelihood of an API being up and running in a random instant. Associated with the concept of availability is that of Time-To-Repair (TTR), which is the time it takes to restore an API once it becomes unavailable. The availability of an API should be able to be verified by exposing a monitoring API, dedicated and low impact (therefore highly available) |
| Accessibility | The ability of an API to be reachable at any instant of time |
| Performances | Usually measured against two values: throughput and latency. Throughput represents the number of requests satisfied in a given interval. Latency represents the amount of time that passes between sending a request and receiving a response (a well-performing API has high throughput and low latency) |
| Reliability | The ability of an API to function correctly and consistently, providing the same QoS despite malfunctions of different nature. It is usually expressed in terms of failures in a given time frame |
| Scalability | The ability to serve requests consistently, efficiently and effectively as their number increases or decreases. It is strictly connected to the concept of accessibility |
| Security | Aspects such as confidentiality, integrity, authorization and authentication |
| Transnationality | The ability of an operation to comply with transactional execution, where required, is part of the QoS |
The subjects (public or private) adhering to the TDH who make data and content available, must take all the necessary steps to guarantee the QoS requirements required by the case of use. This also includes the use of good practices, for example, to ensure performance and scalability, as well as the implementation of mechanisms that ensure the greatest possible bandwidth savings.
| [1] |
«Guidelines on the technical interoperability of Public Administrations» issued by AgID, referred to in paragraph 3.3 of the cited document (please refer to the «Reference Bibliography and Sitography» section at the end of the document for link with redirect to the document) |