Given any complex directed network, a set of acyclic subgraphs can be extracted that will provide valuable information about its hierarchical structure. This Letter presents how the interpretation of the network weight matrix as a transition matrix allows the hierarchical backbone to be identified and characterized in terms of the concepts of hierarchical degree, which expresses the total weigh...

This paper presents a novel algorithm for the gateway placement problem in Backbone Wireless Mesh Networks (BWMNs). Different from existing algorithms, the new algorithm incrementally identifies gateways and assigns mesh routers to identified gateways. The new algorithm can guarantee to find a feasible gateway placement satisfying Quality-of-Service (QoS) constraints, including delay constraint...

An optimization of the energy consumption in network systems has been recently an important research issue. The main challenge is to design, develop and test novel technologies, integrated control strategies and mechanisms for network equipment enabling energy saving by adapting network capacities and resources to current traffic loads and user requirements, while ensuring end-toend Quality of ...

In recent years, overlay networks have emerged as an attractive alternative for supporting value-added services. Due to the difficulty of supporting end-to-end QoS purely in end-user overlays, backbone overlays for QoS support have been proposed. In this paper, we describe a backbone QoS overlay network architecture for scalable, efficient and practical QoS support. In this architecture, we adv...

In the first phase of the NSFNET Backbone, a 56Kbps infrastructure utilized routers based on Fuzzball software [2]. The Phase 1 Backbone used the Hello Protocol for interior routing. At the periphery of the Backbone, the client networks were typically connected by using a gatedaemon ("gated") interface to translate between the Backbone’s Hello Protocol and the interior gateway protocol (IGP) of...

We introduce and study backbone colorings, a variation on classical vertex colorings: Given a graph G = (V, E) and a spanning subgraph H of G (the backbone of G), a backbone coloring for G and H is a proper vertex coloring V → {1, 2, . . .} of G in which the colors assigned to adjacent vertices in H differ by at least two. We study the cases where the backbone is either a spanning tree or a spa...

A traffic matrix is required to design, plan, and manage a telecommunications network. A great deal of work has been carried out to infer such a matrix from link load measurements. Of these, the Tomogravity method has shown some promise. However, in this paper it will be demonstrated that, in many realistic cases, it is possible to obtain even better results using a new method that will be refe...

Introduction There are two major frameworks for providing service guarantees in IP-based networks: The Integrated Services (IS) architecture and the Differentiated Services (DS) architecture. While the IS framework provides service guarantees using a flow-based packet differentiation, the DS architecture differentiates the treatment of aggregates. Though IS is able to provide strong Quality of ...

The theme of this thesis is the enhancement of current IP backbone provisioning practices in the presence of additional network measurements. Current practices are heavily dependent on the intuition of the human operators. Traffic variability, scalability issues, lack of monitoring information, and complex interactions between interand intra-domain routing protocols result in network management...

In wireless ad hoc networks, due to the dynamic topology changes, multi hop communications and strict resource limitations, routing becomes the most challenging issue, and broadcasting is a common approach which is used to alleviate the routing problem. Global flooding is a straightforward broadcasting method which is used in almost all existing topology-based routing protocols and suffers from...