Network function virtualization (NFV) is a concept aimed at achieving telecom grade cloud ecosystem for new‐generation networks focusing on capital and operational expenditure (CAPEX and OPEX) savings. This study introduces empirical throughput prediction model for the virtual network function (VNF) and network function virtualization infrastructure (NFVI) architectures based on Linux kernel. The model arises from the methodology for performance evaluation and modeling based on execution area (EA) distribution by CPU core pinning. EA is defined as a software execution unit that can run isolated on a compute resource (CPU core). EAs are derived from the elements and packet processing principles in NFVIs and VNFs based on Linux kernel. Performing measurements and observing linearity of the measured results open the possibility to apply model calibration technique to achieve general VNF and NFVI architecture model with performance prediction and environment setup optimization. The modeling parameters are derived from the cumulative packet processing cost obtained by measurements for collocated EAs on the CPU core hosting the bottleneck EA. The VNF and NFVI architecture model with performance prediction is successfully validated against the measurement results obtained in emulated environment and used to predict optimal system configurations and maximal throughput results for different CPUs.

Background. The effects of different practices on fault distributions in evolving complex software systems is not fully understood. Software reuse and unit verification are practices used to improve system reliability by minimising the number of late faults. Reused software benefits from already being verified while unit verification aims to find faults early.Aims. We want to study effects of software reuse and unit verification on future modifications, fault densities of software units, and fault distributions.Method. We applied statistical analysis to a sample of 520 units that were reused and modified within four sequential projects from one product line in the telecommunication domain.Results. In reused units, the results of unit verification are correlated to a smaller degree of modifications and decreased fault densities.Conclusion. Unit verification in complex systems may improve system evolution in terms of smaller modifications and decrease of fault densities. The unit verification faults in reused components may be used as predictors of component modification and fault density.

This work-in-progress paper introduces the EU FP7 STREP CloudScale. The contribution of this paper is an overall description of CloudScale's engineering approach for the design and evolution of scalable cloud applications and services. An Electronic Health Record (EHR) system serves as a motivation scenario. The overall CloudScale method describes how CloudScale will identify and gradually solve scalability problems in this existing applications. CloudScale will also enable the modelling of design alternatives and the analysis of their effect on scalability and cost. Best practices for scalability will further guide the design process. The CloudScale method is supported by three integrated tools and a scalability description modelling language. CloudScale will be validated by two case studies.

Background: Software engineering is searching for general principles that apply across contexts, for example, to help guide software quality assurance. Fenton and Ohlsson presented such observations on fault distributions, which have been replicated once. Objectives: We aimed to replicate their study again to assess the robustness of the findings in a new environment, five years later. Method: We conducted a literal replication, collecting defect data from five consecutive releases of a large software system in the telecommunications domain, and conducted the same analysis as in the original study. Results: The replication confirms results on unevenly distributed faults over modules, and that fault proneness distributions persist over test phases. Size measures are not useful as predictors of fault proneness, while fault densities are of the same order of magnitude across releases and contexts. Conclusions: This replication confirms that the uneven distribution of defects motivates uneven distribution of quality assurance efforts, although predictors for such distribution of efforts are not sufficiently precise.

The paper deals with a method developed for software maintenance called remote maintenance shell. It allows software installation, modification and verification on the remote target system without suspending its regular operation. The method is based on remote operations performed by mobile agents. The role of remote maintenance shell in software maintenance is elaborated, as well as its architecture. A case study on version replacement of an object-oriented application is included.

Distributed processing has become inevitable in many areas today. It can be found in localized systems like multiprocessor computers, in client-server network configurations, in computer clusters or in widely dispersed systems like the Internet. Development of effective techniques for task distribution is considered as one of the biggest issues in parallel and distributed operating environment. Over the past years, a number of load balancing methods has been proposed. This paper describes simulation used for methods comparison. Contrary to the vast of known methods, which are based on client/server technology, a few recent methods are based on mobile agents. This article gives short review of achievements in this area and describes simulation used for agents based load balancing methods comparison. The paper also suggests enhancement in load balancing: mobile agents could include fresh node into the system by installing and starting necessary software components.

Fast introduction of new functionality into the existing telecommunication nodes is very important task for software and system designers. One effective way to do this is to move part of the functionality to an additional external platform. By creating generic application components and putting them together, new functionality is introduced into the network. A framework for introduction of new application services for serving multiprotocol communications is discussed.