This article presents an advanced framework for Dynamic Traffic Management (DTM), significantly extending our prior work on minimizing inter-domain traffic costs. The main extension enables cost optimization among multiple sending and multiple receiving domains. The mechanism works for volume and 95thpercentile tariffs. The main paradigm of DTM operation remains unchanged: DTM reacts dynamically on traffic changes on inter-domain links shifting some part of traffic (manageable traffic) from one link to another. This mechanism is based on flow load-balancing, it is centrally controlled by SDN controllers. It requires cooperation between operators receiving and generating traffic. Communication between domain operators is realized by SDN controllers (inter-domain SDN). DTM has been applied to inter-cloud communication for DCs located in different ISP domains. The experiments conducted in the hardware testbed, involving numerous sending and receiving sites, demonstrate that DTM can save up to 36% of the transfer cost.

This article introduces the concept, implementation and evaluation of Dynamic Traffic Management (DTM). This management mechanism minimizes traffic transfer costs on interdomain links. It works for volume and 95 h percentile tariffs. DTM reacts dynamically to traffic changes on inter-domain links shifting some part of traffic (manageable traffic) from one link to another. The management mechanism works in a distributed way. It requires cooperation between operators, namely Internet Service Providers (ISPs), receiving and generating traffic. Communication between ISPs is realized by SDN controllers (inter-domain SDN). DTM has been applied to intercloud communication for Data Centers (DCs) located in different ISP domains. Moreover, it is cloud-agnostic, i.e., DTM does not engage Cloud Service Providers (CSPs) into management procedures. Evaluation performed in the testbed shows that DTM is capable of decreasing ISP costs of transit traffic up to 29%.

Information technology is widely used in processes vital to enterprises.Therefore, IT systems must meet at least the same level of security as required from the business processes supported by these systems.In this paper, we present a view on cybersecurity management as an enterprise-centered process, and we advocate the use of enterprise architecture in security management.Activities such as risk assessment, selection of security controls, as well as their deployment and monitoring should be carried out as a part of enterprise architecture activity.A set of useful frameworks and tools is presented and discussed.

This paper proposes a dynamic traffic management mechanism which addresses the problem of cost-optimal distribution of inevitable inter-domain traffic on multiple links, and enables dynamic overlay traffic management and adaptation to constantly changing traffic patterns to meet cost optimization goals. The mechanism allows for the management of traffic generated by overlay applications such as content delivery platforms, online storage systems, or P2P.

The paper presents a concept of a rating algorithm aiming at overall peer-to-peer traffic reduction (and locality awareness) and decrease of load on costly links, thus diminishing operator's costs. The rating algorithm is not only performed by a sole Oracle, as is typically proposed, but its operation is also supported by a similar entity located in other domains. Due to this concept, a usually omitted fact that the inter-domain routes are asymmetrical is properly dealt with. Simulations performed on a real topology show the usefulness of the presented approach.

The paper presents a concept of the peer-to-peer related traffic optimization. The mechanism is based on the Oracle idea, where a peer is informed on closely located P2P nodes suggesting connection to them. The Oracle gains the relevant information on the basis of BGP databases, where the important extension is related to using a cooperation mechanism between different operators' domains.

The paper presents an analytical modular model of a DiffServ network supporting assured forwarding PHB. Individual DiffServ network elements such as meter/markers and droppers are modeled separately. Additional equations make it possible to describe behavior of a complex DiffServ network in mathematical terms. The modular model makes it possible to calculate several network performance parameters under various configurations and traffic volume. The model can be used for designing networks, is helpful in initial setting of configuration parameters and enables quick evaluation of network performance.

The paper proposes analytical models of two types of multi-RED queues, WRED and RIO-C, serving as droppers in DiffServ networks. Both are scrutinized under two types of configuration of threshold parameters: staggered and overlapped. The proposed analysis uses the M(n)/M/1/K and M(n)/D/1/K queuing models (queuing systems with balking). Additionally, in the case of RIO-C, a Bernoulli scheme is adopted in the model. The models are validated under two types of traffic: ftp-like and web-like. Recommendations on the selection of the most appropriate model are provided.

The paper presents mathematical models for meter/markers serving as DiffServ node elements. Models for two types of token bucket based meter/markers: single rate three color marker and two rate three color marker and a model for a rate estimator based meter/marker, i.e. time sliding window three color marker, are provided. Experimental validation of these models is also presented.

The paper presents a mathematical model of the TCP behavior in a DiffServ network and its empirical validation. The assured forwarding per hop behavior is modeled. The model is modular - individual components of DiffServ nodes are described by separate sets of equations. It makes it easy to develop a model of a system consisting of various types of DiffServ node elements (meters/markers, shaper/droppers) just by changing some of the equations. The input traffic is divided into several traffic aggregates each having a part of a bottleneck capacity dedicated to it.