![](bg8.png)
the spectrum is very high. This performance opens
the possibility of applying a de-fragmentation method
like the ones found in (Velasco et al., 2017) or mod-
ifying the RP-RMLSA formulation to minimize the
network fragmentation.
5 CONCLUSIONS
In this work, we propose a BLP formulation to jointly
solve the regeneration placement, routing, modulation
format, and spectrum assignment problems (known as
RP–RMLSA). The RP–RMLSA model formulated is
both complete and straightforward, considering every
characteristic of the elastic optical network architec-
tures, and regeneration devices. We show through dif-
ferent instances that the optimal number of regenera-
tion sites is one or none, located on different network
nodes depending on the topology. Finally, when re-
generation occurs on a given source–destination node,
it will also regenerate the same node pair but transmit-
ting on the opposite side, solving the problems sym-
metrically.
Future work intends to include a cost of frag-
mentation to the RP–RMLSA formulation, seeking
to minimize both the regeneration cost and the spec-
trum usage on the network links. Also, we intend to
test the model with larger networks trying to reduce
the execution time with OR techniques aiming to face
the computational complexity of the problem. Finally,
formulate an RP algorithm to reach a similar solution
found in the RP–RMLSA model but with consider-
ably lower running time, assessing the trade–off be-
tween complexity and optimality, and compare it with
the hierarchical modeling approach.
ACKNOWLEDGEMENTS
This work received financial support from PI
LII
2020 74, and DGIIP masters scholarship program
from USM, as well as ANID FONDECYT Iniciaci
´
on
11201024.
REFERENCES
Brasileiro,
´
I., Valdemir, J., and Soares, A. (2019). Regen-
erator assignment with circuit invigorating. Optical
Switching and Networking, 34:58–66.
Calder
´
on, F. I., Lozada, A., B
´
orquez-Paredes, D., Olivares,
R., Davalos, E. J., Saavedra, G., Jara, N., and Leiva,
A. (2020). Ber-adaptive rmlsa algorithm for wide-area
flexible optical networks. IEEE Access, 8:128018–
128031.
Chaves, D. A., Carvalho, R. V., Pereira, H. A., Bastos-Filho,
C. J., and Martins-Filho, J. F. (2012). Novel strate-
gies for sparse regenerator placement in translucent
optical networks. Photonic Network Communications,
24(3):237–251.
Chaves, D. A., da Silva, E. F., Bastos-Filho, C. J., Pereira,
H. A., and Almeida, R. C. (2015). Heuristic algo-
rithms for regenerator assignment in dynamic translu-
cent elastic optical networks. In 2015 17th Interna-
tional Conference on Transparent Optical Networks
(ICTON), pages 1–4. IEEE.
Ellis, A. D., Mac Suibhne, N., Saad, D., and Payne, D. N.
(2016). Communication networks beyond the capac-
ity crunch. Philosophical Transactions of the Royal
Society A: Mathematical, Physical and Engineering
Sciences, 374(2062).
Fontinele, A., Santos, I., Dur
˜
aes, G., and Soares, A. (2016).
Achievement of fair and efficient regenerator alloca-
tions in translucent optical networks using the novel
regenerator assignment algorithm. Optical Switching
and Networking, 19:22–39.
ITU-T (2012). Spectral grids for wdm applications: Dwdm
frequency grid. ITU-T G.694.1, Telecommunication
Standardization Sector of ITU, Ginebra, Switzerland.
Kahya, A. (2013). Routing, spectrum allocation and re-
generator placement in flexible-grid optical networks.
PhD thesis, bilkent university.
Klinkowski, M. (2012). On the effect of regenerator place-
ment on spectrum usage in translucent elastic optical
networks. In 2012 14th International Conference on
Transparent Optical Networks (ICTON), pages 1–6.
IEEE.
Poggiolini, P., Bosco, G., Carena, A., Curri, V., Jiang, Y.,
and Forghieri, F. (2014). The gn-model of fiber non-
linear propagation and its applications. Journal of
Lightwave Technology, 32:694–721.
Talebi, S., Alam, F., Katib, I., Khamis, M., Salama, R., and
Rouskas, G. N. (2014). Spectrum management tech-
niques for elastic optical networks: A survey. Optical
Switching and Networking, 13:34–48.
TeleGeography (2020). The state of the network 2020 edi-
tion.
Velasco, L., Vela, A. P., Morales, F., and Ruiz, M. (2017).
Designing, operating, and reoptimizing elastic op-
tical networks. Journal of Lightwave Technology,
35(3):513–526.
Waldman, H. (2018). The Impending Optical Network Ca-
pacity Crunch. Sbfoton Conference, pages 1–3.
Wang, X., Brandt-Pearce, M., and Subramaniam, S. (2015).
Impact of wavelength and modulation conversion
on translucent elastic optical networks using milp.
Journal of Optical Communications and Networking,
7(7):644–655.
Yaghubi-Namaad, M., Rahbar, A. G., and Alizadeh, B.
(2018). Adaptive modulation and flexible resource al-
location in space-division-multiplexed elastic optical
networks. Journal of Optical Communications and
Networking, 10(3):240–251.
Yıldız, B. and Karas¸an, O. E. (2017). Regenerator loca-
tion problem in flexible optical networks. Operations
Research, 65(3):595–620.
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