Editing Quality of service (section)

==Mobile (cellular) QoS==
{{main|Mobile QoS}}
Mobile cellular service providers may offer [[mobile QoS]] to customers just as the wired [[public switched telephone network]] services providers and [[Internet service provider]]s may offer QoS. QoS mechanisms are always provided for [[circuit switched]] services, and are essential for inelastic services, for example [[streaming multimedia]].

Mobility adds complications to QoS mechanisms. A phone call or other session may be interrupted after a [[handover]] if the new [[base station]] is overloaded. Unpredictable handovers make it impossible to give an absolute QoS guarantee during the session initiation phase.