2 research outputs found
Reliable Slicing of 5G Transport Networks with Dedicated Protection
In 5G networks, slicing allows partitioning of network resources to meet
stringent end-to-end service requirements across multiple network segments,
from access to transport. These requirements are shaping technical evolution in
each of these segments. In particular, the transport segment is currently
evolving in the direction of the so-called elastic optical networks (EONs), a
new generation of optical networks supporting a flexible optical-spectrum grid
and novel elastic transponder capabilities. In this paper, we focus on the
reliability of 5G transport-network slices in EON. Specifically, we consider
the problem of slicing 5G transport networks, i.e., establishing virtual
networks on 5G transport, while providing dedicated protection. As dedicated
protection requires large amount of backup resources, our proposed solution
incorporates two techniques to reduce backup resources: (i) bandwidth
squeezing, i.e., providing a reduced protection bandwidth with respect to the
original request; and (ii) survivable multi-path provisioning. We leverage the
capability of EONs to fine tune spectrum allocation and adapt modulation format
and Forward Error Correction (FEC) for allocating rightsize spectrum resources
to network slices. Our numerical evaluation over realistic case-study network
topologies quantifies the spectrum savings achieved by employing EON over
traditional fixed-grid optical networks, and provides new insights on the
impact of bandwidth squeezing and multi-path provisioning on spectrum
utilization
Research on Survivability Strategies of Virtual Network
Virtualization facilitates heterogeneous cloud applications to share the same
physical infrastructure with admirable flexibility, while resource efficiency
and survivability are critical concerns for virtual network embedding (VNE). As
more and more internet applications migrate to the cloud, the resource
efficiency and the survivability of VNs, such as single link failure or
large-scale disaster survivability, have become crucial issues. Separating the
VNE problem into node and link mapping sub-problems without coordination might
cause a high embedding cost. This dissertation presents two independent
approaches to solve the aforementioned challenges. First, we study two-stage
coordinated survivable VNE (SVNE) problem and propose an adaptive path
splitting based SVNE (APSS) scheme. We first develop a concise anchor node
strategy to restrict the solution space of the candidate substrate nodes, which
coordinates node mapping with link mapping to limit the distance spans of the
virtual links. Then, we employ an adaptive path splitting policy to provide
full protection against single-link failures with partial backup resource, and
design an agile frequency slot windows choosing mechanism to mitigate the
spectrum fragmentation for link resource efficiency. Simulation results
demonstrate that the proposed APSS scheme can achieve satisfactory performance
in terms of spectrum utilization and blocking ratio. Second, we propose a
synchronous evacuation strategy for VNs with dual virtual machines (VMs) inside
a disaster risk zone (DRZ), which suffer higher risks than the VNs with single.
The evacuation strategy exploits post-copy technique to sustain the online
service alive and enhances synchronous VM migrations to shorten the dual-VM
evacuation time. Numerical results show that the proposed strategy can
outperform the best-effort scheme in terms of average and total evacuation
times of dual-VMs.Comment: Master Degree Thesis at Chongqing University of Posts and
Telecommunication