http://hdl.handle.net/2117/3132 2013-06-19T12:32:26Z http://hdl.handle.net/2117/19576 Title: Area and laser power scalability analysis in photonic networks-on-chip Authors: Abadal Cavalle, Sergi; Cabellos Aparicio, Alberto; Lázaro Villa, José Antonio; Nemirovsky, Mario; Alarcón Cot, Eduardo José; Solé Pareta, Josep Abstract: In the last decade, the field of microprocessor architecture has seen the rise of multicore processors, which consist of the interconnection of a set of independent processing units or cores in the same chip. As the number of cores per multiprocessor increases, the bandwidth and energy requirements for their interconnection networks grow exponentially and it is expected that conventional on-chip wires will not be able to meet such demands. Alternatively, nanophotonics has been regarded as a strong candidate for chip communication since it could provide high bandwidth with low area and energy footprints. However, issues such as the unavailability of efficient on-chip light sources or the difficulty of implementing all-optical buffering or header processing hinder the development of scalable photonic on-chip networks. In this paper, the area and laser power of several photonic on-chip network proposals is analytically modeled and its scalability is evaluated. Also, a graphene-based hybrid wireless/optical-wired approach is presented, aiming at enabling end-to-end photonic on-chip networks to scale beyond thousands of cores 2013-06-19T12:14:14Z http://hdl.handle.net/2117/19521 Title: A lightweight algorithm for traffic filtering over sliding windows Authors: Sanjuàs Cuxart, Josep; Barlet Ros, Pere; Solé Pareta, Josep; Andriuzzi, Gabriella Abstract: The problem of testing whether a packet belongs to a set of filtered addresses has been traditionally addressed using Bloom filters. They have a small memory footprint and require few memory accesses per query and insertion, while presenting a small probability of false positive. The problem of automatic eviction of filtered addresses after a pre-configured time window is more challenging, since it requires tracking insertion times for later removal. This has been achieved in the literature by replacing the Bloom filter's vector of bits for a vector of timestamps. This approach precisely expires old items from the filter, but has a large memory footprint. We present a novel Bloom filter based data structure that features approximate information expiration. This small extra source of error allows for a more compact filter representation, thus becoming more suitable to fit in more expensive, faster memory. Additionally, our data structure is more flexible in that it allows for balancing the trade-off between filtering and expiration accuracy. Our experiments show that this method can obtain up to orders of magnitude higher overall accuracy than the time-stamp approach using the same amount of memory. 2013-06-05T17:40:23Z http://hdl.handle.net/2117/19488 Title: CAPEX study for grid dependent multi-layer IP/MPLS-over-EON using relative BV-WSS costs Authors: Pedrola Escribà, Òscar; Velasco Esteban, Luis Domingo; Fernández-Palacios, Juan Pedro; Castro Casales, Alberto; Careglio, Davide; Junyent Giralt, Gabriel Abstract: The impact of the frequency grid on the CAPEX required to deploy a multi-layer IP/MPLS-over-EON is analyzed. Results showing significant savings at the electronic layer motivate the introduction of narrower grids with enhanced BV-WSS. 2013-06-03T10:25:47Z http://hdl.handle.net/2117/19438 Title: A comparative study of impairments aware optical networks planning tools Authors: Azodolmolky, Siamak; Angelou, Marianna; Tomkos, Ioannis; Morea, Annalisa; Pointurier, Yvan; Solé Pareta, Josep Abstract: Transparent and translucent optical networks are widely considered as the prime candidates for the core network technology of the future. These networks provide ultra high speed end-to-end connectivity with high quality of service (QoS) and resilience to failures. This will be achieved through appropriate network planning techniques. A downside of transparency, however, is the accumulation of physical layer impairments over long distances, which are difficult to mitigate using purely physical-layer techniques. Considering the impact of physical layer impairments on network planning and operation has received considerable attention from research community. A novel physical layer impairment aware network planning tool is presented in this paper. Its performance is quantitatively compared with results obtained by a state-of-the-art tool under a common network scenario. The differences between the two planning approaches are illustrated and discussed. 2013-05-29T08:12:34Z http://hdl.handle.net/2117/19311 Title: Energy-efficiency and security issues in the Cisco Nexus virtual distributed switching Authors: Peterson, Benjamin; Ricciardi, Sergio; Nin Guerrero, Jordi Abstract: Virtualization technologies have brought with them the promise of increased security and energy saving. Such was the case with the Cisco Nexus virtual switching environment. However, possible security issues of this environment have not been evaluated and the achievable energy savings have not been quantified yet. In particular, it was necessary to investigate whether the security vulnerabilities existing in physical switches had persisted into the virtual environment. This paper provides an evaluation of the energy saving and an analysis of the security implications of the Cisco Nexus virtual distributed switching environment. 2013-05-16T14:10:16Z http://hdl.handle.net/2117/19307 Title: Cuckoo sampling: robust collection of flow aggregates under a fixed memory budget Authors: Sanjuàs Cuxart, Josep; Barlet Ros, Pere; Duffield, Nick; Kompella, Ramana Abstract: Collecting per-flow aggregates in high-speed links is challenging and usually requires traffic sampling to hand le peak rates and extreme traffic mixes. Static selection of sam pling rates is problematic, since worst-case resource usage is or ders of magnitude higher than the average. To address this issue, adaptive schemes have been proposed in the last few years tha t periodically adjust packet sampling rates to network condi tions. However, such proposals rely on complex algorithms and data structures of costly maintenance. As a consequence, adapti ve sampling is still not widely implemented in routers. We present a novel flow sampling based measurement scheme called Cuckoo Sampling that efficiently collects per-flow ag gre- gates, while smoothly discarding information as it exceeds the available memory. After a measurement epoch, it provides a random sample of the input flows, at a close-to-maximum rate as allowed by the available memory budget. Our proposal relies on a very simple data structure, require s few per-packet operations, has a CPU cost that is independen t of the memory budget and traffic profile, and is suitable for hardware implementation. We back the theoretical analysis of the algorithm with experiments with both synthetic and real net work traffic, and show that our algorithm requires significantly l ess resources than existing adaptive sampling schemes 2013-05-16T13:38:48Z http://hdl.handle.net/2117/19281 Title: OSPF-TE extensions for green routing in optical networks Authors: Wang, Jiayuan; Ricciardi, Sergio; Manolova Vasileva, Anna; Ruepp, Sarah; Careglio, Davide; Dittmann, L. Abstract: This paper proposes extensions to the OSPF-TE protocol to enable green routing in GMPLS-controlled optical networks. Simulation results show a remarkable reduction in CO 2 emissions by preferring network elements powered by green energy sources in the connection routing. 2013-05-16T10:11:25Z http://hdl.handle.net/2117/19278 Title: GPON and EP2P: a techno-economic study Authors: Ricciardi, Sergio; Santos Boada, Germán; Careglio, Davide; Domingo Pascual, Jordi Abstract: New services like Video on demand/Internet Protocol Television, Voice over IP and high speed Internet access demand very high bandwidth to provide Triple Play services to the customers. The ADSL/ADLS2+ and the VDSL/VDSL2 copper- wire technologies deteriorate quickly with the distance and will be soon obsolete for supporting the ultra-high bandwidth requirements of the next future. One suitable long term solution for such a high bandwidth demand is employing optical fibers to customers premises (FTTH). In particular, two optical distribution network architectu res, GPON (gigabit passive optical network) and EP2P (E thernet point-to-point), are competing for the network access segment. This paper surveys the two technologies and evalua tes them from a quantitative techno-economic point of view, tr ying to identify which market scenarios are best served by EP2P and which are best served by GPON architectures for supporting the requirement of Triple Play applications . 2013-05-16T09:31:39Z http://hdl.handle.net/2117/19249 Title: Energy-aware routing optimization in dynamic GMPLS controlled optical networks Authors: Wang, J; Ricciardi, Sergio; Fagertun, A.M.; Ruepp, Sarah; Careglio, Davide; Dittmann, L. Abstract: In this paper, routing optimizations based on energy sources are proposed in dynamic GMPLS controlled optical networks. The influences of re-routing and load balancing factors on the algorithm are evaluated, with a focus on different re-routing thresholds. Results from dynamic network simulations show that re-routing strategies can lower CO2 emissions compared to the basic energy source routing scheme, and a lower re-routing threshold achieves more savings. The increased blocking probability brought by using re-routing schemes can be compensated by applying load balancing criteria. A trade-off between blocking probability and obtained CO2 savings is studied. 2013-05-15T13:06:09Z http://hdl.handle.net/2117/19247 Title: Detecting price and search discrimination on the Internet Authors: Mikians, Jakub; Gyarmati, Laszlo; Erramilli, Vijay; Laoutaris, Nikolaos Abstract: Price discrimination, setting the price of a given product for each customer individually according to his valuation for it, can benefit from extensive information collected online on the customers and thus contribute to the profitability of e-commerce services. Another way to discriminate among customers with different willingness to pay is to steer them towards different sets of products when they search within a product category (i.e., search discrimination). Our main contribution in this paper is to empirically demonstrate the existence of signs of both price and search discrimination on the Internet, and to uncover the information vectors used to facilitate them. Supported by our findings, we outline the design of a large-scale, distributed watchdog system that allows users to detect discriminatory practices. 2013-05-15T12:45:19Z http://hdl.handle.net/2117/18977 Title: Demonstration of GMPLS-controlled device power management for next generation green optical networks Authors: Morea, Annalisa; Perelló Muntan, Jordi; Agraz Bujan, Fernando; Spadaro, Salvatore Abstract: We propose GMPLS protocol enhancements enabling dynamic power state management of optoelectronic network devices for setup-time-aware differentiated connection provisioning. Daily energy savings of 56% are demonstrated in a Pan-European-like network compared to always on scenarios. 2013-04-24T10:52:07Z http://hdl.handle.net/2117/18459 Title: ETSI STF 428 - Accelerating deployment of interoperable electronic signatures in Europe Authors: Cruellas Ibarz, Juan Carlos; Caccia, Andrea; Lanz, Konrad; Marzola, Giulianna; Rizzo, Luigi; Velez, Laurent Abstract: This paper provides background information on the strategy of ETSI regarding the production of an integral package of tools for accelerating the production of Interoperable Electronic Signatures across Europe, provides hints on how its different components will fit within the new rationalized framework of European Standards on Electronic Signatures, and finally outlines the main achievements of the ETSI STF-428 project (“Quick fixes to testing of electronic signatures standards“). 2013-03-21T18:46:14Z http://hdl.handle.net/2117/17930 Title: PCE algorithm for traffic grooming and QoS in multi-layer/multi-domain IP over WDM networks Authors: Sócrates Dantas, Joana; Careglio, Davide; Melo Silveira, Regina; Vicente Ruggiero, Wilson; Solé Pareta, Josep Abstract: Differentiated services provision according to clients or applications is an added feature that network operators ambition to fully provide. One of the possible approaches is to map DiffServ into MPLS based network. However in an IP over WDM (Wavelength Division Multiplexing) network data flow traverse multiple layers and, therefore, Class-Type information from the MPLS DiffServ layer is eventually lost. Besides, with the implement of a Path Computation Element (PCE) on multi-layer and multi-domain networks, the bandwidth constraints used to differentiate services are no longer applied. This paper presents a proposal for a QoS DiffServ approach applied on PCE as a traffic grooming technique for WDM core networks and the problematic involved on the application of this technology on multilayer and multi-domain networks. 2013-02-22T11:31:20Z http://hdl.handle.net/2117/17927 Title: Experimental study on the impact of regenerator placement strategies when dynamically provisioning in translucent GMPLS WSON networks Authors: Martínez, Ricardo; Casellas, Ramon; Muñoz, Raul; García Manrubia, Bélen; Pavón Mariño, Pablo; Klinkowski, Miroslaw; Careglio, Davide Abstract: The impact of the regenerator placement strategies when dynamically provisioning connections in translucent WSON is studied. The evaluation is experimentally conducted in the ADRENALINE testbed in terms of the connection blocking. 2013-02-22T10:59:20Z http://hdl.handle.net/2117/17926 Title: Dynamic compact multicast routing on power-law graphs Authors: Pedroso, Pedro; Papadimitriou, Dimitri; Careglio, Davide Abstract: Compact routing schemes address the fundamental tradeoff between the memory space required to store the routing table entries and the length of the routing paths that these schemes produce. This paper introduces the first known name-independent, leaf-initiated dynamic compact routing scheme that allows the distribution of traffic from any source to any set of leaf nodes along a multicast routing path that defines a distribution tree. By means of the proposed scheme, a multicast distribution tree dynamically evolves according to the arrival of leaf-initiated join/leave requests. To evaluate the performance we consider the following metrics: the stretch of the produced routing paths, the size and the number of routing table entries, and the communication cost. The results obtained by simulation on synthetic power law graphs (modeling the Internet topology) show that our scheme can successfully handle leaf-initiated dynamic setup of multicast distribution trees. Two reference multicast routing schemes (the Shortest Path Tree and the Steiner Tree algorithm) are used to compare the performance of the proposed scheme. While increasing the communication cost compared to the Shortest Path Tree, the proposed scheme achieves considerable reduction of the routing table size compared to both reference schemes. Moreover, the stretch of the resulting multicast routing paths show limited deterioration compared to the minimum value obtained with Steiner Trees. 2013-02-22T10:37:56Z