## 2 The Novel Effective DBA Algorithm for Implementation in NG-PON2 Networks  
The Effective Dynamic Bandwidth Algorithm (EDBA) works with the aim of wavelength allocation according to the traffic loading of ONU units. If the ONU traffic loading is higher, then the next wavelength will be assigned so that a transmission window for each wavelength is larger than the \(GT\) data space in this case. In another case, less wavelengths can be allocated for ONU units with reduced traffic loading. By this method, a number of allocated wavelengths for each ONU unit can be varied in different cycles depending on the reported bandwidth requests and assigned transmission window utilization. If the number of ONU units is small, a maximum upstream bandwidth for one ONU unit can be high-large. In this case, the effective EDBA algorithm is trying to allocate more wavelengths to ONU units. If a number of ONU units is high, then each ONU unit can contribute little to the network traffic loading. In this case, the effective EDBA algorithm can allocate fewer wavelengths to the ONU units based on the effective utilization of assigned transmission windows. By this method, the effective EDBA algorithm guarantees a sufficient bandwidth to each ONU unit and avoids wasteful bandwidth spending caused by redundant \(GT\) guard times [31; 32]. The effective DBA algorithm was introduced for consideration in the first next-generation passive optical networks, however, without the optimization of the decision criterion. No such kind of algorithm is introduced for NG-PON2 networks. Compared to the presented algorithms oriented on the effective bandwidth utilization, the novel EDBA algorithm does not determine fixed wavelengths allocated to all ONU units, but it allows the usage of a flexible number of wavelengths based on the bandwidth utilization of utilized wavelengths. So, the implementation of the novel EDBA algorithm in NG-PON2 networks is the novelty of this work. Moreover, the optimization of the decision criterion is an important part of this implementation due to its direct impact on the bandwidth utilization. Because this algorithm can be implemented in the OLT terminal to avoid upstream data collisions, it increases the upstream latency to an acceptable range. The EDBA algorithm can adaptively determine a bandwidth and wavelength allocation for each ONU unit based on the starting cycle time for each free wavelength and on the efficiency of the grant utilization on definitively assigned wavelength. The effective EDBA algorithm arranges wavelengths in the ascending order based on their starting time and begins to allocate a bandwidth to a wavelength with the earliest starting cycle time. The next wavelength will be assigned if the transmitting _TW_ size is larger than a difference _diff_(_i_) with the starting cycle time of adjacent wavelength and simultaneously the _TW_ size is larger compared to the _Rh_ decision criterion and the _GT_ data space, where the _Rh_ decision criterion is a real number used for defining a grant utilization efficiency [31; 32]. The novel EDBA algorithm in NG2-PON networks can be compared with two known DBA methods designed for these networks. For achieving a better bandwidth utilization of the dedicated wavelengths, this work is focused on the effective dynamic bandwidth allocation algorithm with an adaptive allocation of wavelengths to ONU units and on the optimization of the decision criterion that is used for defining a minimum bandwidth utilization of the actual wavelength necessary for possibly allocating the next wavelength. An identification of the optimum decision criterion significantly decreases a time for achievement the effective bandwidth utilization of utilized wavelengths and allows for the adjustment of the _Rh_ value at the wavelength allocation process according to the number of connected ONU units. The NG-PON2 network [29] has an architecture capable of the 40 Gbit/s total network capacity corresponding to four 10 Gbit/s symmetric downstream/upstream data rates available for each wavelength.