NetPDL: An Extensible XML-Based Language for Packet Header Description

Although several applications need to know the format of network packets to perform their tasks, till now, each application uses its own packet description database. This paper addresses this problem by proposing the NetPDL, an XML-based language for describing packet headers, which has the potential of enabling the realization of a common, application-independent protocol description database that can be shared among several applications. Further, common functionalities related to the protocol database can be implemented in a library, which can be a basic building block for implementing networking applications

SME food suppliers versus large retailers: perspectives in the international supply chains

none3noThe market share of international retail chains substantially increased from the beginning of the nineties. The supplier’s market has been adapted to the evolutions of retailers’ market in terms of modified purchasing processes. The concentration of large food retailers has been much faster than the same process among manufacturers. Due to these changes, the requirements towards food industry suppliers grew in number and quality. Thus it is generally true that the nature of the buyer-supplier relationship in retailing has been undergoing dramatic changes. Important literature has described these emerging relationships as "partnerships" or "strategic alliances," as opposed to the traditional "arm's length" type of associations. But these conditions are likely to change especially in the relationships between small and medium suppliers and large retailers. The paper shows how the relationships between suppliers and retailers are experiencing several important changes, above all at international level. In particular, the analysis is focused on the Italian food SME suppliers related with international large retailers. Considering the focus of this paper, in-depth interviews to 28 Italian food SME suppliers have been conducted in early 2007. Results have been analyzed and compared to the retailers’ point of view, resulting from public reports (such as Annual report, CSR report, etc.) to understand retail companies’ approach to SME suppliers. Considering the main topics of such relations and the selection criteria used by retailers, one of the main results of the analysis is that the unbalance of power in the relation is not necessarily a negative condition, as the growth of SME suppliers is stimulated by an improving attitude to operate with large retailers. Retailers reserve a wide space on their shelves to SME references because they contribute to increase the variety of merchandising and ensure a more tight control on the supply chain (traceability). At the same time, the strong pressure on price and the required organizational qualifications lead to a selection process, in which smaller manufacturers seem to be the more vulnerable actors.openC. Pepe; F. Musso; M. RissoC., Pepe; Musso, Fabio; M., Riss

Modeling Complex Packet Filters with Finite State Automata

Designing an efficient and scalable packet filter for modern computer networks becomes each day more challenging: faster link speeds, the steady increase in the number of encapsulation rules (e.g., tunneling) and the necessity to precisely isolate a given subset of traffic cause filtering expressions to become more complex than in the past. Most of current packet filtering mechanisms cannot deal with those requirements because their optimization algorithms either cannot scale with the increased size of the filtering code, or exploit simple domain-specific optimizations that cannot guarantee to operate properly in case of complex filters. This paper presents pFSA, a new model that transforms packet filters into Finite State Automata and guarantees the optimal number of checks on the packet, also in case of multiple filters composition, hence enabling efficiency and scalability without sacrificing filtering computation time

CrownLabs - A Collaborative Environment to Deliver Remote Computing Laboratories

The coronavirus pandemic hit the entire education sector hard. All students were sent home and lectures started to be delivered through video-conferencing systems. CrownLabs is an open-source project providing an answer to the problem of delivering remote computing laboratories. Simplicity is one of its main characteristics, requiring nothing but a simple web browser to interact with the system and being all heavyweight computations performed at the university premises. Cooperation and mentoring are also encouraged through parallel access to the same remote desktop. The entire system is built up using components from the Kubernetes ecosystem, to replicate a "cloud grade" infrastructure, coupled with custom software implementing the core business logic. To this end, most of the complexity has been delegated to the infrastructure, to speed up the development process and reduce the maintenance burden. An extensive evaluation has been performed in both real and simulated scenarios to validate the overall performance: the results are encouraging, as well as the feedback from the early adopters of the system

On the Efficiency of Packet Telephony

This paper presents a study on the efficiency of packet switching in providing toll quality telephone services. Packet switching is appealing for the implementation of a commercial telephone network because it features lower cost and higher manageability than circuit switching, and enables integration of real-time and non real-time services. This work compares the real-time efficiency of packet switching and circuit switching, i.e., the volume of voice traffic being guaranteed deterministic quality related to the amount of network resources used. For this purpose, we developed a call level simulator which allows a general topology network to be studied. The simulator performs call admission control according to the availability of the resources required to provide a deterministic delay bound for each call. Statistical data on accepted and rejected calls are the simulation output. Results show that packet size - possibly constrained by the protocol in use - is a key factor in determining the real-time efficiency. The packet size which maximizes real-time efficiency is devised analytically

Unilateral leg swelling in a newborn

A female neonate was born with asymmetric lower limbs, the right leg appearing enlarged, with thickened, reddish-purple skin and ectasic superficial reticulum (figure 1A,B). Limb pulses were present and symmetrical. The girl's family history and prenatal scans were unremarkable. Laboratory findings were within the normal range, except for a mild thrombocytopenia (90 000/μL), which spontaneously resolved during the next few days. A leg X-ray and the Doppler analysis ruled out the presence of calcifications and venous varices, respectively. Ultrasound showed significant skin thickening, with marked dermal hypertrophy and hyperechogenicity. Magnetic resonance showed circumferential thickening of the derma, with mild hypertrophy of some perforating vessels (figure 2). A biopsy of the right thigh showed capillary malformations on histology. edpract;archdischild-2020-320450v1/BLKF1F1BLK_F1Figure 1(A, B) Hypertrophy of the right lower limb, with large capillary malformation extending to the gluteus and the external genitalia. edpract;archdischild-2020-320450v1/BLKF2F2BLK_F2Figure 2Axial THRIVE magnetic resonance scan of the thighs' proximal third, showing circumferential dermal thickening and inhomogeneity of the right leg's subcutaneous tissue. QUESTIONS: Based on the clinical picture and investigations results, which is the most likely diagnosis?Beckwith-WiedemannCLOVES syndromeKlippel-Trenaunay syndromeKaposiform hemangioendotheliomaHow can the diagnosis be confirmed?CT with PETLymphoscintigraphyGenetic testingNone of the above, the diagnosis is clinicalWhat is the mainstay of management?Conservative with follow-upPharmacotherapySclerotherapySurgeryWhich of the following complications can occur?ScoliosisGlaucomaUrinary and gastrointestinal bleedingAll of the above Answers can be found on page 02

An Efficient Data Exchange Algorithm for Chained Network Functions

In-network function chaining often involves the deployment of multiple applications into a single, possibly multi-tenant, middlebox. This approach has gained much interest since new network paradigms, such as Software Defined Networking (SDN) and Network Function Virtualization (NFV), have been proposed to virtualize resources as well as network functions. In this scenario, it is very common to move data (e.g., packets) from an application to another by means of a switching module that is in charge of chaining network functions in the correct order, also ensuring an adequate level of isolation between any two virtualized components. With this purpose in mind, this paper proposes an efficient algorithm to handle the communication between the internal soft-switch and the heterogeneous network functions that are executed on the same server. Our proposal is designed with the aim of dealing with high speed packet processing, hence an extensive performance evaluation is also provided to prove the goodness of our solution in this context

Transient numerical assessment of race car dry-sump oil under different maneuvers

A numerical assessment of a dry-sump oil system was performed by Computational Fluid Dynamics (CFD). Unlike conventional cars, race cars are subjected to high accelerations that induce oil sloshing. Hence, dry-sump oil systems are required to collect the oil outside of the engine prior to be pumped inside of it again. To avoid engine malfunctions, the dry-sump must guarantee continuously oil suction in every maneuver. To perform such simulations, the model was subjected to different car maneuvers extracted from data acquisition available from real race car, showing that single and combined maneuvers, such as acceleration, braking and turnings can induce downward, upward and lateral accelerations higher than 2g during several seconds. Therefore, four different single maneuvers (acceleration, deceleration, turn right and turn left) as well as a set of contaminated maneuvers (braking and turning) were studied. Simulations were achieved by mean of the Volume of Fluid Method (VOF) for a air-oil system. The influence of the turbulence modeling was also investigated. First a forerunner design was analyzed and both the race car tests and CFD simulations showed that for the most extreme maneuvers (pure braking and combined with braking with turning right) the original design failed before the end of the maneuvers by air suction in the pump inlet. In consequence, the dry-sump was redesigned and assessed under these extreme conditions until to ensure stable oil aspiration.Publicado en: Mecánica Computacional vol. XXXV, no. 7.Facultad de Ingenierí