Dynamic Virtual Network Restoration with Optimal Standby Virtual Router Selection

Title form PDF of title page, viewed on September 4, 2015Dissertation advisor: Deep MedhiVitaIncludes bibliographic references (pages 141-157)Thesis (Ph.D.)--School of Computing and Engineering and Department of Mathematics and Statistics. University of Missouri--Kansas City, 2015Network virtualization technologies allow service providers to request partitioned, QoS guaranteed and fault-tolerant virtual networks provisioned by the substrate network provider (i.e., physical infrastructure provider). A virtualized networking environment (VNE) has common features such as partition, flexibility, etc., but fault-tolerance requires additional efforts to provide survivability against failures on either virtual networks or the substrate network. Two common survivability paradigms are protection (proactive) and restoration (reactive). In the protection scheme, the substrate network provider (SNP) allocates redundant resources (e.g., nodes, paths, bandwidths, etc) to protect against potential failures in the VNE. In the restoration scheme, the SNP dynamically allocates resources to restore the networks, and it usually occurs after the failure is detected. In this dissertation, we design a restoration scheme that can be dynamically implemented in a centralized manner by an SNP to achieve survivability against node failures in the VNE. The proposed restoration scheme is designed to be integrated with a protection scheme, where the SNP allocates spare virtual routers (VRs) as standbys for the virtual networks (VN) and they are ready to serve in the restoration scheme after a node failure has been identified. These standby virtual routers (S-VR) are reserved as a sharedbackup for any single node failure, and during the restoration procedure, one of the S-VR will be selected to replace the failed VR. In this work, we present an optimal S-VR selection approach to simultaneously restore multiple VNs affected by failed VRs, where these VRs may be affected by failures within themselves or at their substrate host (i.e., power outage, hardware failures, maintenance, etc.). Furthermore, the restoration scheme is embedded into a dynamic reconfiguration scheme (DRS), so that the affected VNs can be dynamically restored by a centralized virtual network manager (VNM). We first introduce a dynamic reconfiguration scheme (DRS) against node failures in a VNE, and then present an experimental study by implementing this DRS over a realistic VNE using GpENI testbed. For this experimental study, we ran the DRS to restore one VN with a single-VR failure, and the results showed that with a proper S-VR selection, the performance of the affected VN could be well restored. Next, we proposed an Mixed-Integer Linear Programming (MILP) model with dual–goals to optimally select S-VRs to restore all VNs affected by VR failures while load balancing. We also present a heuristic algorithm based on the model. By considering a number of factors, we present numerical studies to show how the optimal selection is affected. The results show that the proposed heuristic’s performance is close to the optimization model when there were sufficient standby virtual routers for each virtual network and the substrate nodes have the capability to support multiple standby virtual routers to be in service simultaneously. Finally, we present the design of a software-defined resilient VNE with the optimal S-VR selection model, and discuss a prototype implementation on the GENI testbed.Introduction -- Literature survey -- Dynamic reconfiguration scheme in a VNE -- An experimental study on GpENI-VNI -- Optimal standby virtual router selection model -- Prototype design and implementation on GENI -- Conclusion and future work -- Appendix A. Resource Specification (RSpec) in GENI -- Appendix B. Optimal S-VR Selection Model in AMP

Schemes for building an efficient all-optical virtual private network.

by Tam Scott Kin Lun.Thesis submitted in: October 2005.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.Includes bibliographical references (leaves 58-64).Abstracts in English and Chinese.Chapter 1. --- Introduction --- p.1Chapter 1.1. --- Optical Networks --- p.1Chapter 1.1.1. --- IP over Optical Networks --- p.1Chapter 1.1.2. --- Challenges in Optical Networks --- p.4Chapter 1.2. --- Virtual Private Networks (VPN) --- p.5Chapter 1.2.1. --- CE Based VPN --- p.6Chapter 1.2.2. --- Network Based VPN --- p.7Chapter 1.2.2.1. --- MPLS Layer 2 VPN --- p.8Chapter 1.2.2.2. --- MPLS Layer 3 VPN --- p.9Chapter 1.2.3. --- Optical VPN --- p.9Chapter 1.2.4. --- Challenges in VPN Technologies --- p.11Chapter 1.3. --- Objective of this Thesis --- p.11Chapter 1.4. --- Outline of this Thesis --- p.12Chapter 2. --- Architecture of an All-Optical VPN --- p.13Chapter 2.1. --- Introduction --- p.13Chapter 2.2. --- Networking Vendor Activities --- p.13Chapter 2.3. --- Service Provider Activities --- p.15Chapter 2.4. --- Standard Bodies Activities --- p.16Chapter 2.5. --- Requirements for All-Optical VPN --- p.17Chapter 2.6. --- Reconfigurability of an All-Optical VPN --- p.19Chapter 2.7. --- Switching Methods in All-Optical VPN --- p.20Chapter 2.8. --- Survivability of an All-Optical VPN --- p.23Chapter 3. --- Maximizing the Utilization Of A Survivable Multi-Ring WDM Network --- p.25Chapter 3.1. --- Introduction --- p.25Chapter 3.2. --- Background --- p.25Chapter 3.3. --- Method --- p.26Chapter 3.3.1. --- Effect on packet based services --- p.28Chapter 3.3.2. --- Effect on optical circuit based services --- p.28Chapter 3.4. --- Simulation results --- p.29Chapter 3.5. --- Chapter Summary --- p.36Chapter 4. --- Design of an All-Optical VPN Processing Engine --- p.37Chapter 4.1. --- Introduction --- p.37Chapter 4.2. --- Concepts of Optical Processors --- p.38Chapter 4.3. --- Design Principles of the All-Optical VPN Processing Engine --- p.40Chapter 4.3.1. --- Systolic System --- p.41Chapter 4.3.2. --- Design Considerations of an Optical Processing Cell --- p.42Chapter 4.3.2.1. --- Mach-Zehnder Structures --- p.43Chapter 4.3.2.2. --- Vertical Cavity Semiconductor Optical Amplifier --- p.43Chapter 4.3.2.3. --- The Optical Processing Cell --- p.44Chapter 4.3.3. --- All-Optical VPN Processing Engine --- p.47Chapter 4.4. --- Design Evaluation --- p.49Chapter 4.5. --- Application Example --- p.50Chapter 4.6. --- Chapter Summary --- p.54Chapter 5. --- Conclusion --- p.55Chapter 5.1. --- Summary of the Thesis --- p.55Chapter 5.2. --- Future Works --- p.56Chapter 6. --- References --- p.5

Resilient virtual topologies in optical networks and clouds

Optical networks play a crucial role in the development of Internet by providing a high speed infrastructure to cope with the rapid expansion of high bandwidth demand applications such as video, HDTV, teleconferencing, cloud computing, and so on. Network virtualization has been proposed as a key enabler for the next generation networks and the future Internet because it allows diversification the underlying architecture of Internet and lets multiple heterogeneous network architectures coexist. Physical network failures often come from natural disasters or human errors, and thus cannot be fully avoided. Today, with the increase of network traffic and the popularity of virtualization and cloud computing, due to the sharing nature of network virtualization, one single failure in the underlying physical network can affect thousands of customers and cost millions of dollars in revenue. Providing resilience for virtual network topology over optical network infrastructure thus becomes of prime importance. This thesis focuses on resilient virtual topologies in optical networks and cloud computing. We aim at finding more scalable models to solve the problem of designing survivable logical topologies for more realistic and meaningful network instances while meeting the requirements on bandwidth, security, as well as other quality of service such as recovery time. To address the scalability issue, we present a model based on a column generation decomposition. We apply the cutset theorem with a decomposition framework and lazy constraints. We are able to solve for much larger network instances than the ones in literature. We extend the model to address the survivability problem in the context of optical networks where the characteristics of optical networks such as lightpaths and wavelength continuity and traffic grooming are taken into account. We analyze and compare the bandwidth requirement between the two main approaches in providing resiliency for logical topologies. In the first approach, called optical protection, the resilient mechanism is provided by the optical layer. In the second one, called logical restoration, the resilient mechanism is done at the virtual layer. Next, we extend the survivability problem into the context of cloud computing where the major complexity arises from the anycast principle. We are able to solve the problem for much larger network instances than in the previous studies. Moreover, our model is more comprehensive that takes into account other QoS criteria, such that recovery time and delay requirement

Scalable algorithms for QoS-aware virtual network mapping for cloud services

Both business and consumer applications increasingly depend on cloud solutions. Yet, many are still reluctant to move to cloud-based solutions, mainly due to concerns of service quality and reliability. Since cloud platforms depend both on IT resources (located in data centers, DCs) and network infrastructure connecting to it, both QoS and resilience should be offered with end-to-end guarantees up to and including the server resources. The latter currently is largely impeded by the fact that the network and cloud DC domains are typically operated by disjoint entities. Network virtualization, together with combined control of network and IT resources can solve that problem. Here, we formally state the combined network and IT provisioning problem for a set of virtual networks, incorporating resilience as well as QoS in physical and virtual layers. We provide a scalable column generation model, to address real world network sizes. We analyze the latter in extensive case studies, to answer the question at which layer to provision QoS and resilience in virtual networks for cloud services

Survivable Cloud Networking Services

Cloud computing paradigms are seeing very strong traction today and are being propelled by advances in multi-core processor, storage, and high-bandwidth networking technologies. Now as this growth unfolds, there is a growing need to distribute cloud services over multiple data-center sites in order to improve speed, responsiveness, as well as reliability. Overall, this trend is pushing the need for virtual network (VN) embedding support at the underlying network layer. Moreover, as more and more mission-critical end-user applications move to the cloud, associated VN survivability concerns are also becoming a key requirement in order to guarantee user service level agreements. Overall, several different types of survivable VN embedding schemes have been developed in recent years. Broadly, these schemes offer resiliency guarantees by pre-provisioning backup resources at service setup time. However, most of these solutions are only geared towards handling isolated single link or single node failures. As such, these designs are largely ineffective against larger regional stressors that can result in multiple system failures. In particular, many cloud service providers are very concerned about catastrophic disaster events such as earthquakes, floods, hurricanes, cascading power outages, and even malicious weapons of mass destruction attacks. Hence there is a pressing need to develop more robust cloud recovery schemes for disaster recovery that leverage underlying distributed networking capabilities. In light of the above, this dissertation proposes a range of solutions to address cloud networking services recovery under multi-failure stressors. First, a novel failure region-disjoint VN protection scheme is proposed to achieve improved efficiency for pre-provisioned protection. Next, enhanced VN mapping schemes are studied with probabilistic considerations to minimize risk for VN requests under stochastic failure scenarios. Finally, novel post-fault VN restoration schemes are also developed to provide viable last-gap recovery mechanisms using partial and full VN remapping strategies. The performance of these various solutions is evaluated using discrete event simulation and is also compared to existing strategies

QoS Design Consideration for Enterprise and Provider’s Network at Ingress and Egress Router for VoIP protocols

Compliance with the Service Level Agreement (SLA) metric is a major challenge in a Multiprotocol Label Switching Virtual Private Network (MPLS VPN) because mandatory models must be maintained on both sides of the MPLS VPN in order to achieve end-to-end service levels. The end-to-end service of an MPLS VPN can be degraded owing to various issues such as distributed denial of service (DDoS), and Random Early Detection (RED) that prevents congestion and differentiates between legitimate and illegitimate user traffic. In this study, we propose a centralized solution that uses a SLA Violation Detector (SLAVD) and intrusion detection to prevent SLA violation

Resilience options for provisioning anycast cloud services with virtual optical networks

Optical networks are crucial to support increasingly demanding cloud services. Delivering the requested quality of services (in particular latency) is key to successfully provisioning end-to-end services in clouds. Therefore, as for traditional optical network services, it is of utter importance to guarantee that clouds are resilient to any failure of either network infrastructure (links and/or nodes) or data centers. A crucial concept in establishing cloud services is that of network virtualization: the physical infrastructure is logically partitioned in separate virtual networks. To guarantee end-to-end resilience for cloud services in such a set-up, we need to simultaneously route the services and map the virtual network, in such a way that an alternate routing in case of physical resource failures is always available. Note that combined control of the network and data center resources is exploited, and the anycast routing concept applies: we can choose the data center to provide server resources requested by the customer to optimize resource usage and/or resiliency. This paper investigates the design of scalable optimization models to perform the virtual network mapping resiliently. We compare various resilience options, and analyze their compromise between bandwidth requirements and resiliency quality