ific delay time (also called equalization delay) for each of the con- nected ONTs. Another tool for improving QoS in the uplink direction is the dynamic bandwidth assignment (DBA), which enhances the uplink utilization of PON ports by providing the possibility for higher-bandwidth services for users who require greater change in the allocated bandwidth. DBA is based on service priorities, where the prior- ities are set separately for each ONT, as well as minimum and maximum bandwidth for each ONT. Typically, higher-priority service is voice, then video, and after that data ser- vices (data services typically refer to network-neutral Internet access service). The QoS specifics for different services are specified in the service level agreements. The OLT on Table 4.5 QoS types for GPON. QoS type Bandwidth (T-CONT type) QoS requirements Traffic type T-CONT type 1 Jitter = 0, very low delay Fixed Constant Bit Rate (CBR) traffic such as voice T-CONT type 2 Higher delay than Assured Committed Information T-CONT 1 Rate (CIR) traffic such as TV T-CONT type 3 Does not guarantee delay Non-assured Variable Bit Rate (VBR) traffic such as video T-CONT type 4 Best effort approach Best-effort Web browsing, FTP, email, etc. (Internet access) T-CONT type 5 Mix of the previous four Best-effort General traffic types of T-CONT types 4 QoS for Fixed Ultra-Broadband the operator's side grants the bandwidth based on the SLA, service priorities, and the current state of the ONT. Higher priority refers primarily to lower delay (necessary for voice services, for example) or higher assured bandwidth (e.g. for IPTV, which is TV broadcast over the IP network with guaranteed QoS). The first NG-PON1 refers to 10 Gbit/s PON, i.e. XG-PON. It was created to support multiple services across multiple market segments, which included the consumer segment, business services, and the mobile backhaul network. Such services in G-PON and XG-PON include Internet access, IPTV, and VoIP, as well as certain legacy services, such as digital telephony (i.e. pla