A network model for routing-fault-free wavelength selection in WRONoCs design

Abstract

Emerging technologies in on-chip communication domain bring about new combinatorial optimization problems at design automation. We address the Wavelength Selection Problem in Wavelength-Routed Optical Networks-on-Chip (WRONoCs), where wavelengths act as signal carriers for initiator-to-target communication, so that signals are the least interfering and routing faults are prevented. We present this novel engineering problem and model it as a constrained shortest path on acyclic networks, propose a graph-based mathematical formulation and an iterative procedure on incremental graphs to solve the model on realistic data.

Logic programming approaches for routing fault-free and maximally parallel wavelength-routed optical networks-on-chip (Application paper)

“…The second problem (Nonato et al 2017) comes from the observation that, once the maximum parallelism level is found, it is also of interest to design the WRONoC in the safest way, despite small variations that might occur in the fabrication process. In order to maximize the probability that the device is able to function correctly, the selected wavelengths used as carriers have to be as far as possible one from the other.…”

“…In order to maximize the probability that the device is able to function correctly, the selected wavelengths used as carriers have to be as far as possible one from the other. Such problem was approached in (Nonato et al 2017) through a MILP formulation. In this work, we presented a Constraint Logic Programming on Finite Domains (CLP(FD)) program, showed that it has performances competitive with the MILP approach and found that it is easier to modify it to take into consideration further aspects in the WRONoC design.…”

“…In fact, in order to minimize the likelihood of routing faults, a selected resonance M r,i should be as far as possible not only from the other selected resonances M s, j , but also from all the resonance wavelengths of the selected radii (λ R,i for all the selected R and all i), independently from the fact that they are also selected as carriers or not. Considering this effect, the MILP model in (Nonato et al 2017) can no longer be used and a major rewriting is required, because the problem can no longer be modeled as a constrained shortest path.…”

“…After finding the maximum obtainable parallelism n λ , one has to choose a suitable solution among the (possibly, many) solutions providing the same optimal value of parallelism. In the paper by Nonato et al (2017), it was found that the wavelengths found when solving the first problem could be unevenly spread in the available spectrum. This introduced a second problem: given n R and n λ , find n R radii values and n R × n λ wavelengths (n λ per radius) such that the selected wavelengths are as evenly spread as possible.…”

“…We detail the ASP program used to solve the problem, and experimentally compare its performance with a Mixed-Integer Linear Programming (MILP) model. Another related problem was solved in (Nonato et al 2017) through a MILP formulation. In this paper, we address the same problem in another logic language, namely Constraint Logic Programming on Finite Domains (CLP(FD)), and show that the CLP(FD) formulation is competitive with MILP and that it is easier to modify.…”