ve evaluation of service quality by human end-users). One should note that different QoS parameters may also be interrelated (e.g. higher variation of the link capacity influences the delay variation for the affected services that use that link). 7.3 Interconnection and QoS Interconnection relates to connection links between autonomous network domains (i.e. different autonomous systems), which may belong to different network providers that provide access and/or transit. The interconnection by itself is an important part of QoS, which is needed to be properly dimensioned regarding the traffic requirements for all service types that go through the interconnection points. For example, the QoS sup- port at the interconnection for voice traffic over legacy fixed and mobile networks (i.e. TDM-based networks such as PSTN and PLMN) is based on traditional QoS voice parameters, such as limited end-to-end delays provided by guaranteed bitrates with TDM in each of the two voice directions, admission control (accepting new call when enough resources end-to-end, i.e. voice channels in both directions, can be established end-to-end, thorough all networks and interconnection points), etc. Besides voice, the interconnection is also important for the best-effort and network neutral Internet traffic. However, the interconnection of the best effort Internet traf- fic is harder to design than traditional interconnection for voice traffic. That is due to the variable bitrates of the aggregate Internet traffic, which results in Internet traffic being self-similar and bursty by nature [6], and hence unpredictable at a given time (unlike legacy voice traffic). Of course, interconnection at the Internet traffic exchanges 7 Broadband QoS Parameters, KPIs, and Measurements depends upon the volume of traffic that goes out of the originating network domain (the egress traffic), as well as number of interconnection links in parallel with other net- work domains and their capacities (for higher reliability as well as for ingress and egress Int