ld note that IP packets are not individually transferred through the intercon- nection points (i.e. IPXs). Typically, a given telecom operator (as network provider) first aggregates IP packets (based on previous packet classification) into VPNs. So, there can be separate VPN tunnels created for carrier-grade VoIP, for signaling (i.e. control) traf- fic, for business services traffic, for network neutral Internet traffic, for traffic between CDN points of presence (CDN POPs), etc. Such VPN tunnels are established between the two end-peers which can be gateway nodes (or edge routers) placed on the border between each of the two networks that interconnect. So, all traffic to/from telecom operator networks traverses through national and inter- national IPXs. Therefore, the IPXs are the most appropriate place to enforce end-to-end QoS provisioning, besides the need for QoS encouragement and/or enforcement at the broadband/ultra-broadband fixed and/or mobile access networks. KPIs for Real-Time Services The most important QoS parameters which are important to all parties (customers, service providers, telecom operators, NRAs, and the public) are referred to as KPIs. However, they are primarily performance indicators which are derived by using network 7 Broadband QoS Parameters, KPIs, and Measurements performance metrics (when KPIs are related to service utilization). Such indicators are measured on the basis on various network counters (e.g. in routers, switches, user equip- ment) and are essential for operation and maintenance of services and for support of the ICT service business models (e.g. selected KPIs optionally or mandatory may be speci- fied in the contractual agreements between the services providers and the customers). Defining KPIs is targeted to help in reporting, auditing and other efforts related to QoS (and for long-term QoS sustainability of ICT services sold to the customers). However, KPIs must be used in context with a certain service or part of its delivery, otherwise they may become meaningless. B