, security control; QoS mapping between the core and access networks (and vice versa); as well as the possibility for traffic management over Ethernet (needed to guarantee QoS). 3 QoS in NGN and Future Networks Internet access IPTV with service loT with VolP with services Ethernet-based core networks (with QoS) Mobile Business broadband Ethernet broadband access customer networks access networks networks (with QoS) Residential Small business fixed broadband customer networks access networks QoS - Quality of service NGN - Next generation network loT - Internet of Things VolP - Voice over IP IPTV - IP television VPN - Virtual private networks Figure 3.8 Ethernet-based NGN architecture. The interface between different operator networks is the Ethernet Network-Network Interface (E-NNI). The Ethernet User to Network Interface (E-UNI) includes the IEEE 802.1Q standard. The Carrier Ethernet uses Ethernet virtual connections (EVCs) in one of three possible service types: Ethernet line (E-line): point-to-point EVC Ethernet local area network (E-LAN): multipoint-to-multipoint EVC Ethernet tree (E-tree): routed multipoint EVC. In Ethernet-based NGNs the EVC extends between two E-UNIs. Overall, the EVC- based services are provisioned by using several IEEE standards, from which the most important for Carrier Ethernet are the following three: IEEE 802.1 for virtual LAN [16]: each virtual local area network (VLAN) is uniquely identified within the given Ethernet network by a Q-tag (it is also referred to as VLAN ID). The Q-tag field (i.e. VLAN ID) has a length of 12 bits, which results in 4096 different values (from which two are reserved for network administration). IEEE 802.1ad for provider bridges [17]: these add a tag in the Ethernet frame, called an S-tag. Similar to the Q-tag, its length is 12 bits, which results in 4094 possible instances (2 of 4096 values for the S-tag are reserved also for administration). IEEE 802. lah for provider backbone bridges (PBBs) [18]: they give additional source and destination medium access