Squeezed Protection in Elastic Optical Networks Subject to Multiple Link
Failures
Abstract
Elastic optical network (EON) is fast becoming a key solution for
designing optical network with better usage of spectrum resources or
other objectives of interest to tenant and/or operators. A primary
concern of EONs is to protect the network against failures of its
elements, because this kind of event can provoke the loss of substantial
amount of traffic. In this paper, we propose a new mixed integer linear
programming (MILP) formulation for protecting the network traffic
against multiple link failures. The key idea is to use bandwidth
squeezing together with grooming capability to provide few extra traffic
for protection and guarantee a minimum bandwidth for each
source–destination node pair under multiple failure events. The
proposed formulation solves the virtual topology design problem jointly
with the grooming, routing, modulation and spectrum allocation (RMSA)
tasks. Due to the non-deterministic polynomial time (NP-hard) nature of
the proposed MILP formulation, a heuristic strategy (referred to as
two-step MILP) for large networks is also proposed. The solutions and
performance of the proposed MILP formulation and two-step MILP analyzed
through case studies in a small network. In addition, the performance of
three large networks is assessed for cases scenarios where connections
are under different service-level agreement (SLA). In view of proposed
formulation and two-step MILP, it is possible to identify the
configurations that ensure better usage of spectrum resources with
different kinds of protection against single or multiple link failures.