Mary Luz Mouronte

TOPOLOGICAL ANALYSIS OF COMPLEX OPTICAL TRANSPORT NETWORKS

SDH (Synchronous Digital Hierarchy) is the standard technology for information transmission in broadband optical networks. Unlike the Internet, SDH networks are strictly planned — rings, meshes, stars or tree-branches topologies are designed to connect their basic elements. In this work we show that the SDH network operated by Telefonica in Spain presents a power-law scaling in the degree distribution (P(k) ~ k-γ) both at the national and provincial levels. The empirically obtained scaling exponents γ are consistent with those observed in other heterogeneous complex networks. The Spanish SDH network also displays small world properties with a high clustering and short path length similar to the Internet routers network. The province subnetworks experience similar traits with regards to such properties. Considering factors such as network design policies, user demand, geographical location and types of equipment, we propose an ad hoc computational model in order to reproduce these topological properties.

A Model for the Complex Topology of SDH Telecommunication Networks

SDH (Synchronous Digital Hierarchy) is the standard technology for the information transmission in broadband optical networks. Taking into account geographical and technological variables that affect the engineering planning,we propose an ad-hoc model that reproduces the complex topology observed in the Spanish SDH network.

On the topology of optical transport networks

Synchronous Digital Hierarchy (SDH) is the standard technology for information transmission in broadband optical networks. Unlike systems with unplanned growth, such as those of natural origin or the Internet network, the SDH systems are strictly planned as rings, meshes, stars or tree-branches structures designed to connect different equipments. In spite of that, we have found that the SDH network operated by Telef?nica in Spain shares remarkable topological properties with other real complex networks as a product of its evolution since 1992. In fact, we have found power-law scaling in the degree distribution (N?P(k) = k??) and small-world networks properties. The complexity found in SDH systems was reproduced by two models of complex networks, one of them considers real planning directives that take into account geographical and technological variables and the other one is based in the compatibility among SDH equipments.

Global Behaviour of Fixed-Pathways Dynamics in Technological Networks

Complex technological networks usually present distinct characteristics that strongly affect some of its properties.One of them is the fact that the dynamical processes that develop in these networks are usually along predefined pathways, with limited capabilities of seeking alternative routes. One example are large corporation software networks,where several flow processes take place and most of them have predefined paths. In the present work, we propose a simple model to describe the global characteristics of this kind of dynamical interacting processes, where interactions are described as zero-sum games between node pairs. We find that our model delivers interesting and unexpected emerging properties, namely a type of bifurcation transition of the number of efficient processes as a function of the total network load.

Modification Propagation in Complex Networks

To keep up with rapidly changing conditions, business systems and their associated networks are growing increasingly intricate as never before. By doing this, network management and operation costs not only rise, but are difficult even to measure. This fact must be regarded as a major constraint to system optimization initiatives, as well as a setback to derived economic benefits. In this work we introduce a simple model in order to estimate the relative cost associated to modification propagation in complex architectures. Our model can be used to anticipate costs caused by network evolution, as well as for planning and evaluating future architecture development while providing benefit optimization.

Complexity in the Systems Network of a Telecommunication Operator

Complex networks of a technological nature have much importance in modern life. In many cases, the large amount of components and their intricate interrelationship can affect some properties, such as their reliability, stability or security. One example of such networks is the highly interconnected systems that provide support to operations and business in large organizations, such as companies or corporations. This paper analyzes the complexity in the systems network of Telefónica España (TE); we propose a model to understand its behaviour and evolution. The results allow us to establish mechanisms, which ensure the reliability and determine the effect of the modifications into the network.

Ambient Intelligence in Network Management

This paper presents a technical method for solving the main provisioning problems on transmission networks automatically: communications, naming, misalignments, etc. This solution incorporates users’ experience and business knowledge in expert agents which execute specific actions on the Network Management System (NMS) when an error occurs. The human intervention is reduced so that OPEX and network management are improved.