Catálogo de publicaciones - libros

Reliability of active measurement results is an omnipresent issue in all existing measurement tools. Till this day, no reference point exists that would enable to compare measurement methods in efficiency and reliability. Partially, this is due to inability to attribute any particular probability model to both probing results as well as to the traffic probes interfere with. This paper proposed to analyze spectrum of measurement results in search for a reliable reference point. It is discovered that spectrum distribution of probing results are linearly dependent to linear changes in traffic.

When multiple flows using different versions of TCP exist together on the network, they are influenced seriously between each other. One of methods to overcome this problem is to control such flows individually by identifying the TCP versions of each flow. Thus, this process needs a method to identify online which TCP version is used for each flow. In this paper, we first focus on the increase speed of the congestion window in two different versions of TCP, which are TCP Reno and HSTCP (High Speed TCP). We also show that increasing rate of congestion window has remarkable characteristics in each TCP version. We then propose a method to identify flow by using the characteristics. We show that TCP Reno and HSTCP can be completely identified by using our proposed method.

End-to-End (E2E) flow monitoring is useful for observing performance of networks such as throughput, jitter and delay. Typically, E2E flow monitoring is carried out at end hosts with known tools such as iperf. However, the end-host approach may not be easily deployed in a large-scale network because of high cost and administrative overhead. Therefore, in this paper, we propose a new E2E flow monitoring method based on IP Flow Information eXport (IPFIX) that could provide QoS metrics such as throughput, retransmission rate, delay, and jitter for TCP flows and SIP-signalled RTP flows. We have extended the IPFIX templates for carrying QoS-related fields, and developed the E2E flow monitoring function with the open source that could be embedded into routers. From experiments, it was shown that the performance of TCP and RTP flows could be easily examined with the IPFIX-based approach.

IPTV just has been spread throughout the world. For the success of IPTV service, it is a key feature to satisfy QoS (Quality of Services) of total IPTV solution, such as tolerable channel zapping time.A related work reduces IPTV channel zapping time using a home gateway to take a role of IGMP-proxy. However, the related work considers the only case that a subscriber selects an adjacent channel of the current one. Additionally the related work requires a home gateway for each subscriber. In this paper, we propose a solution for the two problems using rating server without home gateway.Settop boxes instead of home gateways join or leave the adjacent channel groups for fast changes to the adjacent channels. Additionally settop boxes obtain an expected channel list by sending a query message to rating server and join the expected multicast groups in advance.

Network services, resources, protocols, and communication technologies give rise to multiple dimensions of heterogeneity in an enterprise, resulting in a complex administration and management operation. The administrative challenge is further exacerbated by the fact that multiple enterprises share resources and users, giving rise to semantic conflicts. While Policy-Based Network Management (PBNM) provides an effective means of automating and simplifying administrative tasks, it can also cause conflicts between policies meant for separate network entities, consequently giving rise to policy heterogeneity. In order to address issues of network and policy heterogeneity, we propose a policy engineering framework using the tried and tested system development methodologies from Software Development Life Cycle (SDLC) and apply it to PBNM language engineering. We present an XML based policy specification language, X-Enterprise, its corresponding UML meta-model along with a context sensitive and adaptive implementation framework. Use of XML and UML affords an open standard for cross-architecture implementation and use of existing UML tools for consistency and conflict analysis.

Traditional telecommunications service providers are undergoing a transition to a shared infrastructure in which multiple services will be delivered by peer and server computers interconnected by IP networks. IP transport networks that can transfer packets according to differentiated levels of QoS, availability and price are a key element to generating revenue through a rich offering of services. Automated service and network management are essential to creating and maintaining a flexible and agile service delivery infrastructure that also has much lower operations expense than existing systems. In this paper we focus on the SLA-based IP packet transport service on a core network infrastructure and we argue that the above requirements can be met by a self-management system based on autonomic computing and virtual network concepts. We present a control and management system architecture based on this approach.

This work presents the design and validation of a new hybrid Heuristic-Genetic Algorithm (HGA) for the management of the Survivability Dynamic Routed and Wavelength Assignment (S-DRWA), based on lightpath protection sharing, and applied on a IP/WDM transport network.

The use of Internet as an ubiquitous communication platform puts a strong demand on service providers regarding the assurance of multiple service levels consistently. Designing flexible and simple service-oriented management strategies is crucial to support multiconstained applications conveniently and to obtain a deployable and sustainable service quality offer in multiservice IP networks. In this context, this paper proposes the use of a self-adaptive QoS and SLS management strategy sustained by a service-oriented traffic admission control scheme to ensure the negotiated quality levels. A proof-of-concept of the proposed strategy is provided, illustrating its ability to self-adapt and control efficiently distinct QoS requirements in multiservice IP networks.

This paper presents a component framework for rapidly building and operating the visual interfaces for network management. It can easily and dynamically assemble visual components that can monitor and control their target network devices or sub-systems into an active document as a visual interface for the whole network. Since each visual component is an autonomous programmable entity, it can define network management protocols in addition to its visual interface inside it. End-users or administrators can manually customize smart spaces through user-friendly GUI-based manipulations for editing documents. This paper presents the design for this framework and describes its implementation and a practical application already being used for sensor networks in the real world.

The multi-homing technology can provide an extended coverage area via distinct access technologies. Also, it is able to redirect a flow from one interface to another without reinitiating the flow. However, there is no suitable multi-homing technology for ubiquitous network environment at the moment. To provide multi-homing schemes into the ubiquitous environment, various related researches should be studied. Therefore, we proposed primary path selection algorithm which can provide a ubiquitous access and Flow redirection.