1 research outputs found
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