In data networks, the most used protocol is the IP protocol and it is essentially the Web that has allowed the development of lntemet and IP Protocol. IP protocol provides flexibility, but today there is no tested mechanisms enabling to give a real Quality of Service (QoS). QoS is necessary for new applications such as Voice over IP (VolP) to enable transmission of voice through packet network. New architectures are developed to offer QoS for future telecommunications networks.