2. Service quality

The term "quality of service" covers a multitude of notions

• It can refer to any behavior that voluntarily deviates from the default behavior of a network in order to improve its performance, or that of a particular application.

• This can involve providing applications with guarantees on throughput, delay and transmission jitter. These are known as "strict guarantees".

• In general, it's more a matter of defining several traffic classes to which applications will adhere according to their needs.