## 5 Results  
### Simulation Setup  
We ran simulations for two realistic large network topologies: the European backbone network called Euro28 (28 nodes, 84 links, average link length of 625 km) and the US national network called US26 (26 nodes, 82 links, average link length of 755 km) [30]. Both topologies are shown in Figure 5. We assumed that each network link was a bundle of 7 SMFs (single-mode fibers) and each fiber offered 4 THz spectrum (320 slices of 12.5 GHz width each). The general assumptions on the SS-FON architecture were similar as in References [11; 12]. In particular, we considered four modulation formats, namely, BPSK, QPSK, 8-QAM, and 16-QAM. Based on the data presented in References [26; 27], we assumed that coherent transponders transmitted/received the signals of 3 slices (i.e., 37.5 GHz). The bit rates supported by a transponder depended on the applied modulation format and are presented in Table 1. In the case where the requested bit rate exceeded the transponder capacity using a particular modulation format, the request was served within one spectral Sch allocated via an adequate number of adjacent slices. For instance, if the request bit rate was 300 Gb/s, using the QPSK modulation format, 3 transponders were required with a spectral Sch consisting of 9 slices. In turn, if the 8-QAM modulation format was selected, the same 300 Gb/s request would need 2 transponders with 6 slices. Each established Sch was separated from neighboring SChs by 1 slice (12.5 GHz) guard-band. The transmission reaches of the modulation formats were taken from References [27] and are reported in Table 1. However, we want to stress that the presented network model (Section 3) and algorithms (Section 4) are generic, and they can be easily adapted to other parameters describing the applied modulation formats. According to our previous experiments reported in Reference [11], the following three numbers of transponders that can be predeployed in the network have been selected for the simulations: 10,000; 15,000; and 20,000. It should be noted that in the considered SS-FON scenario, bandwidth blocking probability can occur due to the fact of two reasons: lack of spectrum resources or lack of transponders. The three selected numbers of transponders assure that we would be able to analyze the three different cases in the simulations: (i) the blocking was mostly due to the lack of transponders (budget of 10,000 transponders); the blocking was due to the lack of both transponders and spectrum (budget of 15,000 transponders); and (iii) the blocking was mostly due to the lack of spectrum (budget of 20,000 transponders). For dynamic routing (i.e., establishing the arriving request in the network), we applied the ARBR algorithm proposed in Reference [11] with the tuning parameter \(\alpha\) = 0.8, according to the tuning process presented in Reference [11]. We use \(k\) = 5 shortest paths applied to generate candidate lightpaths including routing and regeneration configurations. Traffic requests were generated randomly with bit rates from 50 Gb/s to 1 Tb/s, changing with a 50 Gb/s granularity. The requests arrived at the network according to a Poisson process with an average arrival rate of \(\lambda\) requests per time-unit. In turn, the lifetime of each request followed a negative exponential distribution with an average of \(1/\mu\). Consequently, the offered total traffic load was \(\lambda/\mu\) normalized traffic units (NTUs). As the average bit rate of a single request was 525 Gb/s, 100 NTUs corresponded to about 52.5 Tb/s of the offered traffic load. For each of the simulated traffic load given in NTUs, we generated a set of 60,000 requests; however, the first 5000 requests were not included in the analysis in order to allow the network to reach a stable condition. Most of the previous works that examine dynamic routing in optical network considered only one traffic profile assuming uniform traffic distribution among all network nodes.