. latency), jitter (i.e. delay variation), and packet loss (e.g. it is important for real-time services such as voice). The important quality criterion is to avoid degrada- tion of IAS for provision of specialized services, which can be accomplished by having sufficient network capacity (for carrying the highest volume of traffic during the day). What is sufficient network capacity? It is network capacity on each link and on each path that can transfer IP traffic with no more than 70% load in the peak hour (due to statistical multiplexing of bursty Internet traffic), without noticeable congestion. Suffi- cient capacity for IAS is assessed by performing QoS measurements with and without specialized services over a given broadband/ultra-broadband network. 8.2 Degradations of Internet Access Service Network neutrality refers directly to IAS and therefore the main regulatory issues concerning QoS are related to detection of its potential degradation. For that purpose 8.2 Degradations of Internet Access Service Transit provider Transit provider Transit Transit Transit ISP-A provider provider ISP-B provider Transit provider Access Interconnection part Access between ISP-A and ISP-B ISP - Internet service provider Figure 8.1 End-to-end Internet communication model. appropriate tools for monitoring the IAS are required, to know its quality [4]. Internet communication in general refers to end-to-end communication over the public Inter- net, which includes ISPs on both ends and an interconnection leg between them which may consist of one or more transit networks (Figure 8.1). Considering the end-to-end Internet communication model, there are two main types of degradation of IAS: Degradation of IAS as a whole. This refers to IAS provided by telecom operators to the end customer, which however is the basis for all OTT (i.e. data) services used by the end-user. To identify possible cases of IAS as a whole degradation requires monitoring the service quality of the IAS in fixed and mobile networks by measuring the main IP netwo