1 research outputs found
Regenerator placement in optical networks
Cataloged from PDF version of article.Increase in the number of users and resources consumed by modern applications
results in an explosive growth in the traffic on the Internet. Optical networks
with higher bandwidths offer faster and more reliable transmission of data and
allows transmission of more data. Fiber optical cables have these advantages over
the traditional copper wires. So it is expected that optical networks will have a
wide application area.
However, there are some physical impairments and optical layer constraints
in optical networks. One of these is signal degradation which limits the range of
optical signals. Signals are degraded during transmission and below a threshold
the signals become useless. In order to prevent this, regenerators which are
capable of re-amplifying optical signals are used. Since regeneration is a costly
process, it is important to decrease the number of regenerators used in an optical
network.
To increase the reliability of the network, two edge-disjoint paths between
each terminal on the network are to be constructed. So the second path could
be used in case of a failure in transmitting data on an edge of the first path.
Considering these requirements, selecting the nodes on which regenerators are to
be placed is an important decision.
In this thesis, we discuss the problem of placing signal regenerators on optical
networks with restoration. An integer linear program is formulated for this problem.
Due to the huge size and other problems of the formulation, it is impractical
to use it on large networks. For this reason, a fast heuristic algorithm is proposed
to solve this problem. Three methods are proposed to check the feasibility when
a fixed set of regenerators are placed on specific nodes. Additionally, a branch
and bound algorithm which employs the proposed heuristic is developed to find the optimal solution of our problem. Performance of both the heuristics and
the branch and bound method are evaluated in terms of number of regenerators
placed and solution times of the algorithms.Özkök, OnurM.S