Compression of Textual Column-Oriented Data

Column-oriented data are well suited for compression. Since values of the same column are stored contiguously on disk, the information entropy is lower if compared to the physical data organization of conventional databases. There are many useful light-weight compression techniques targeted at specific data types and domains, like integers and small lists of distinct values, respectively. However, compression of textual values formed by skewed and high-cardinality words is usually restricted to variations of the LZ compression algorithm. So far there are no empirical evaluations that verify how other sophisticated compression methods address columnar data that store text. In this paper we shed a light on this subject by revisiting concepts of those algorithms. We also analyse how they behave in terms of compression and speed when dealing with textual columns where values appear in adjacent positions

On the design and development of emulation platforms for NFV-based infrastructures

Network Functions Virtualisation (NFV) presents several advantages over traditional network architectures, such as flexibility, security, and reduced CAPEX/OPEX. In traditional middleboxes, network functions are usually executed on specialised hardware (e.g., firewall, DPI). Virtual Network Functions (VNFs) on the other hand, are executed on commodity hardware, employing Software Defined Networking (SDN) technologies (e.g., OpenFlow, P4). Although platforms for prototyping NFV environments have emerged in recent years, they still present limitations that hinder the evaluation of NFV scenarios such as fog computing and heterogeneous networks. In this work, we present NIEP: a platform for designing and testing NFV-based infrastructures and VNFs. NIEP consists of a network emulator and a platform for Click-based VNFs development. NIEP provides a complete NFV emulation environment, allowing network operators to test their solutions in a controlled scenario prior to deployment in production networks

NIEP: NFV infrastructure emulation platform

Network Functions Virtualization (NFV) presents several advantages over traditional network architectures, such as flexibility, security, and reduced CAPEX/OPEX. However, virtualizing network functions usually executed on specialized hardware (e.g., firewall, DPI, load balancer) and employing innovative technologies (e.g., OpenFlow, P4) increases the challenges of designing, testing, and deploying network infrastructures and services. Although platforms for prototyping NFV environments have emerged in recent years, they still present limitations that hinder the evaluation of specific NFV scenarios, such as fog computing and heterogeneous networks. In this paper, we present NIEP: a platform for designing and testing NFV-based infrastructures and Virtualized Network Functions (VNFs) through the integration of a well-known network emulator (Mininet) and a novel platform for Click-based VNFs development (Click-on-OSv). NIEP provides a complete NFV emulation environment, allowing network operators to test their solutions in a controlled scenario prior to deployment in production networks. As main advantages, NIEP allows the emulation of heterogeneous scenarios, which can be easily migrated to production environments. An experimental scenario is defined to analyze NIEP's performance in terms of VNFs boot time and throughput. Further, NIEP's advantages and shortcomings are discussed and compared to existing emulation platforms