Server resource dimensioning and routing of service function chain in NFV network architectures

The Network Function Virtualization (NFV) technology aims at virtualizing the network service with the execution of the single service components in Virtual Machines activated on Commercial-off-the-shelf (COTS) servers. Any service is represented by the Service Function Chain (SFC) that is a set of VNFs to be executed according to a given order. The running of VNFs needs the instantiation of VNF instances (VNFI) that in general are software components executed on Virtual Machines. In this paper we cope with the routing and resource dimensioning problem in NFV architectures. We formulate the optimization problem and due to its NP-hard complexity, heuristics are proposed for both cases of offline and online traffic demand. We show how the heuristics works correctly by guaranteeing a uniform occupancy of the server processing capacity and the network link bandwidth. A consolidation algorithm for the power consumption minimization is also proposed. The application of the consolidation algorithm allows for a high power consumption saving that however is to be paid with an increase in SFC blocking probability

Migration energy aware reconfigurations of virtual network function instances in NFV architectures

Network function virtualization (NFV) is a new network architecture framework that implements network functions in software running on a pool of shared commodity servers. NFV can provide the infrastructure flexibility and agility needed to successfully compete in today's evolving communications landscape. Any service is represented by a service function chain (SFC) that is a set of VNFs to be executed according to a given order. The running of VNFs needs the instantiation of VNF instances (VNFIs) that are software modules executed on virtual machines. This paper deals with the migration problem of the VNFIs needed in the low traffic periods to turn OFF servers and consequently to save energy consumption. Though the consolidation allows for energy saving, it has also negative effects as the quality of service degradation or the energy consumption needed for moving the memories associated to the VNFI to be migrated. We focus on cold migration in which virtual machines are redundant and suspended before performing migration. We propose a migration policy that determines when and where to migrate VNFI in response to changes to SFC request intensity. The objective is to minimize the total energy consumption given by the sum of the consolidation and migration energies. We formulate the energy aware VNFI migration problem and after proving that it is NP-hard, we propose a heuristic based on the Viterbi algorithm able to determine the migration policy with low computational complexity. The results obtained by the proposed heuristic show how the introduced policy allows for a reduction of the migration energy and consequently lower total energy consumption with respect to the traditional policies. The energy saving can be on the order of 40% with respect to a policy in which migration is not performed

Optical communications and networking solutions for the support of C-RAN in a 5G environment

The widespread availability of mobile devices such as tablets and smartphones has led to fast-increasing mobile data traffic in the last few years [...

Effectiveness of segment routing technology in reducing the bandwidth and cloud resources provisioning times in network function virtualization architectures

Network Function Virtualization is a new technology allowing for a elastic cloud and bandwidth resource allocation. The technology requires an orchestrator whose role is the service and resource orchestration. It receives service requests, each one characterized by a Service Function Chain, which is a set of service functions to be executed according to a given order. It implements an algorithm for deciding where both to allocate the cloud and bandwidth resources and to route the SFCs. In a traditional orchestration algorithm, the orchestrator has a detailed knowledge of the cloud and network infrastructures and that can lead to high computational complexity of the SFC Routing and Cloud and Bandwidth resource Allocation (SRCBA) algorithm. In this paper, we propose and evaluate the effectiveness of a scalable orchestration architecture inherited by the one proposed within the European Telecommunications Standards Institute (ETSI) and based on the functional separation of an NFV orchestrator in Resource Orchestrator (RO) and Network Service Orchestrator (NSO). Each cloud domain is equipped with an RO whose task is to provide a simple and abstract representation of the cloud infrastructure. These representations are notified of the NSO that can apply a simplified and less complex SRCBA algorithm. In addition, we show how the segment routing technology can help to simplify the SFC routing by means of an effective addressing of the service functions. The scalable orchestration solution has been investigated and compared to the one of a traditional orchestrator in some network scenarios and varying the number of cloud domains. We have verified that the execution time of the SRCBA algorithm can be drastically reduced without degrading the performance in terms of cloud and bandwidth resource costs

Trade-off between power and bandwidth consumption in a reconfigurable xhaul network architecture

The increasing number of wireless devices, the high required traffic bandwidth, and power consumption will lead to a revolution of mobile access networks, which is not a simple evolution of traditional ones. Cloud radio access network technologies are seen as promising solution in order to deal with the heavy requirements defined for 5G mobile networks. The introduction of the common public radio interface (CPRI) technology allows for a centralization in BaseBand unit (BBU) of some access functions with advantages in terms of power consumption saving when switching off algorithms are implemented. Unfortunately, the advantages of the CPRI technology are to be paid with an increase in required bandwidth to carry the traffic between the BBU and the radio remote unit (RRU), in which only the radio functions are implemented. For this reason, a tradeoff solution between power and bandwidth consumption is proposed and evaluated. The proposed solution consists of: 1) handling the traffic generated by the users through both RRU and traditional radio base stations (RBS) and 2) carrying the traffic generated by the RRU and RBS (CPRI and Ethernet flows) with a reconfigurable network. The proposed solution is investigated under the lognormal spatial traffic distribution assumption. After proposing resource dimensioning analytical models validated by simulation, we show how the sum of the bandwidth and power consumption may be minimized with the deployment of a given percentage of RRU. For instance we show how in 5G traffic scenarios this percentage can vary from 30% to 50% according to total traffic amount handled by a switching node of the reconfigurable network

Optimizing the Cloud Resources, Bandwidth and Deployment Costs in Multi-Providers Network Function Virtualization Environment

The introduction of network function virtualization (NFV) leads to a new business model in which the Telecommunication Service Provider needs to rent cloud resources to infrastructure provider (InP) at prices as low as possible. Lowest prices can be achieved if the cloud resources can be rented in advance by allocating long-term virtual machines (VM). This is in contrast with the short-term VMs that are rented on demand and have higher costs. For this reason, we propose a proactive solution in which the cloud resource rent is planned in advance based on peak traffic knowledge. We illustrate the problem of determining the cloud resources in cloud infrastructures managed by different InPs and so as to minimize the sum of cloud resource, bandwidth and deployment costs. We formulate an integer linear problem (ILP) and due to its complexity, we introduce an efficient heuristic approach allowing for a remarkable computational complexity reduction. We compare our solution to a reactive solution in which the cloud resources are rented on demand and dimensioned according to the current traffic. Though the proposed proactive solution needs more cloud and bandwidth resources due to its peak allocation, its total resources cost may be lower than the one achieved when a reactive solution is applied. That is a consequence of the higher cost of short-term VMs. For instance, when a reactive solution is applied with traffic variation times of ten minutes, our proactive solution allows for lower total costs when the long-term VM rent is lower than the short-term VM one by 33%

Experimental investigation on beach morphodynamical process near river mouth

Physical model study on wave influences on river-mouth depositional process is presented. Experiments were performed in a wave basin in order to determine erosion and accretion area due to the combined wave - current flows. An inflow glass channel was designed to reproduce a river mouth model in a 3D wave basin made with a sand bottom. The tests were carried out under three different conditions: River current, waves, wave -current interaction. Measurements of wave heights, beach profiles and bathymetric profiles were made. The results show that in the presence of combined wave-current flows, erosion areas are more evident in vicinity of a mouth with depth and width values greater than depth and width values of inflow channel

Bismuth-based quadruple therapy following H. Pylori eradication failures: A multicenter study in clinical practice

Background & Aims: Helicobacter pylori (H. pylori) eradication in patients who failed one or more therapeutic attempts remains challenging. This study aimed to assess the efficacy of three-in-one capsules bismuth-based quadruple therapy (Pylera®) in these patients managed in clinical practice. Methods: This was a prospective, open-label, multicenter study enrolling consecutive, adult patients with persistent H. pylori infection following at least one standard therapy. All patients received a rescue quadruple therapy with Pylera (3 capsules four times daily) and esomeprazole 20 mg (1 tablet twice daily) for 10 days. H. pylori eradication was assessed by using Urea Breath Test 4-6 weeks following therapy ending. H. pylori eradication rates, compliance, and side-effects were calculated. Results: A total of 208 patients in the 9 participating centres were enrolled. Overall, 180 patients were successfully cured from the infection, accounting for 86.5% (95% CI 81.9-91.2) and 92.3% (95% CI 88.6-96.1) eradication rates at intention-to-treat analysis and at per protocol analysis, respectively. Cure rates were similar across patients who failed one to three previous therapy attempts, but the success rate fell to 67% after 4 or more therapy failures. Compliance to therapy was good in 198 (95.2%) patients, whilst in 7 (5.3%) cases the therapy was interrupted within 5 days due to side effects. A total of 97 (46.6%) patients complained of at least one side effect; nausea, diarrhea and vomiting were the most frequently reported. Conclusions: Our study found that this bismuth-based quadruple therapy is highly effective as second-line and rescue therapy for H. pylori eradication in clinical practic

Bismuth-based quadruple therapy following H. Pylori eradication failures: A multicenter study in clinical practice

Background & Aims: Helicobacter pylori (H. pylori) eradication in patients who failed one or more therapeutic attempts remains challenging. This study aimed to assess the efficacy of three-in-one capsules bismuth-based quadruple therapy (Pylera®) in these patients managed in clinical practice. Methods: This was a prospective, open-label, multicenter study enrolling consecutive, adult patients with persistent H. pylori infection following at least one standard therapy. All patients received a rescue quadruple therapy with Pylera (3 capsules four times daily) and esomeprazole 20 mg (1 tablet twice daily) for 10 days. H. pylori eradication was assessed by using Urea Breath Test 4-6 weeks following therapy ending. H. pylori eradication rates, compliance, and side-effects were calculated. Results: A total of 208 patients in the 9 participating centres were enrolled. Overall, 180 patients were successfully cured from the infection, accounting for 86.5% (95% CI 81.9-91.2) and 92.3% (95% CI 88.6-96.1) eradication rates at intention-to-treat analysis and at per protocol analysis, respectively. Cure rates were similar across patients who failed one to three previous therapy attempts, but the success rate fell to 67% after 4 or more therapy failures. Compliance to therapy was good in 198 (95.2%) patients, whilst in 7 (5.3%) cases the therapy was interrupted within 5 days due to side effects. A total of 97 (46.6%) patients complained of at least one side effect; nausea, diarrhea and vomiting were the most frequently reported. Conclusions: Our study found that this bismuth-based quadruple therapy is highly effective as second-line and rescue therapy for H. pylori eradication in clinical practic