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Network Virtualization in Wireless
Communication- a review
Dr.YogeshYashwantPundlik1
Mrs. Gauri Yogesh Pundlik2 Dr.M.Prameela3
1
Professor &Head Department of EEE 2Assistant Professor 3
ProfessorEEE Department
Department of ECE
yogesh4037@rediffmail.com pundlikgauri@gmail.com
prameela.m@bvrit.ac.in
1&2Kamala Institute of Technology & Science, Singapur, Telangana State, India
3BVRIT Narasapur Telangana State, India
Abstract: There are traditional wired networks. With the advancement in networking wireless telecommunication &
computer networks were developed. Virtualization in wired networks is common nowadays. There is necessary of
virtualization in the wireless computer networks is to get economic utilization of the existing hardware appliances. There
are other benefits too. This paper discusses the requirements of virtualization of functions of network, benefits of
virtualization of network functions and comparison of NFV and SDN technologies and their complementarity to each
other.
Key words: Virtualization, WiFi, load balancing, Cellular network, Internet of Things, Network Function
Virtualization(NFV),Software Defined Networking (SDN), AP (Access Point), WAP (Wireless Access Point), Smart Home,
Logically Isolated Network partitions (LINP), Hypervisor and container programs
I.Introduction
Virtualization is a process of combining hardware and software resources. NFV is an ingenuity to transfer the
“Network Services” sector through virtualizing the network services by replacing the dedicated hardware with
Virtual Machines.Network functions can be combined into a single entity call as a virtual network. The virtual
network is a software based administrative entity. [1]Virtualization can improve efficiency and utilization and
supports customized service and multi-occupancy of the devices in the network. In traditional networks, the
problems such as dissimilar communication technologies, heterogeneity of devices belonging to various vendors,
application-specific QoS requirements, massive inflow of data, and unpredictable network conditions. Apart from
this, capital cost involved for expansion of existing networks is huge. And when the network expansion takes place,
the operational cost also increases. The control and management of huge networks poses other problems. The
virtualization of wireless communication /computer network is a challenging task. One of the major challenges in
wireless virtualization is how to virtualize wireless links. Consideration of unique features such as limited resource
usage, signal interference etc. which do not happen in wired networks. Features of wireless links should support
both the requirements such as coherence and isolation. Network virtualization should provide scheduling methods
for transmission across different LINPs.NFV is to separate network functions from dedicated hardware
devices/appliances and to use Virtual Machines instead of physical routers, physical firewalls and physical load
balancers. The services can be performed on standard x86 servers, when the Hypervisor controls the network
functions. The ability to scale up and scale down according to our needs and requirements. For example we
purchased a cloud / server which can support 5000 customers.[2],[3] After paying for these number of
users/customers we would like to fully utilize its capacity. Upon growth of the communication business, we need to
go for investment in the hardware. But here with the NFV we can avoid investing in a new server hardware and
make use of the existing hardware by way of virtualization. The architecture of the is shown in the figure (1) below.
Science, Technology and Development
Volume X Issue VIII AUGUST 2021
ISSN : 0950-0707
Page No : 180
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Figure(1) Architecture of Network Function Virtualization
The architecture of the network function virtualization is shown in the above figure (1). It consists of various blocks.
On the right hand side the NFV manager which manages all the functions such as allocation of virtual links, creating
virtual storage as and when need arises. The manager functions dynamically such as to solve the problem of traffic
congestion / saturation during important/interesting cricket/football match. During such situation of matches, there
will be heavy traffic on the network leading to requirement of additional links as well as storage space even beyond
the existing capacity of the server hardware. In upper layer of the architecture virtual applications such as voice,
virtual HLR/HSS, virtual access points. In below layer, there are three sublayers. NFVI sub-layer is for the virtual
infrastructure such as virtual computing facility, virtual storage space and virtual network with virtual links. Middle
sub-layer is interface between the bottom hardware resources and virtual machines.[4] In lower sub-layer consists of
hardware resources on which the computing is done with storage and network functions operate in installed
hardware. Second methodology for implementation of virtualizationis to install virtual access points in a single
physical AP.This approach will enable better sharing of limited wireless resources. In this case, virtualization
happens in the AP/WAP which is another approach of applying virtualization in WiFi networks.
II. What is to be virtualized?
The following table denotes the different functions in the traditional networks to be virtualized using the NFV
technology. Mainly the focus is on to virtualize the hardware components in the communication networks viz:
switching elements as switches, routers, broadband network gateways etc, mobile network nodes:HLR/HSS GPRS
support nodes & others, customer premise equipment like home routers, set-top boxes and other appliances/devices
employed for tunneling,traffic analysis, signaling, control plane and application optimization.
Network element to be
virtualized Its Function
Switching elements Broadband network gateways, carrier grade NAT (network address translation), routers
Mobile network nodes HLR/HSS, Gateway, GPRS support node, radio network controller, various node B
functions
Customer Premise Equipment Home routers, set-top boxes
Tunneling Gateway elements IPsec/SSL virtual private network gateways
Traffic analysis Deep packet inspection (DPI), quality of experience measurement
assurance service assurance, service level agreement (SLA) monitoring, testing and diagnostics
signaling session border controllers, IP multimedia subsystem components
control plane/access functions AAA servers, policy control and charging platforms
application optimization content delivery networks, cache servers, load balancers, accelerators
security firewalls, virus scanners, intrusion detection systems, spam protection
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Volume X Issue VIII AUGUST 2021
ISSN : 0950-0707
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III.Benefits of Virtualization
There are number of benefits of virtualization as such only important are listed below but not limited to:
(i) Enhanced flexibility in scaling up and scaling down the network when need arises during heavy traffic
conditions and vice-versa.
(ii) Enhanced service agility to support new faster service rollouts. Faster modifications in the networks
can be done even in few seconds to adopt to the network condition of heavy traffic.
(iii) Operation becomes simple & easy to manage since the changes are to be done in the software
programs of billion lines. The changes in the programs can also be done automatically.
(iv) Faster innovation due to a software-administered network that eliminates the need for hardware
changes.
(v) The CAPEX- capital expenditure incurred towards the purchase of new hardware for the expansion of
communication business and OPEX- operational costs involved in the operation & maintenance of
hardware of different vendors. The virtualization results in the reduction in both of these costs /
expenditures hence NFV results in cost-effective networks. The cost in physical routers, physical
firewalls and physical load balancers can be reduced by virtual routers, virtual firewalls and virtual
load balancers using virtual machines and virtual storage.
(vi) Security has been major challenge in networks. Operators are interested to provide services to the
customers at the same time operators want provision of security in virtual space and firewall.
(vii) If the physical hardware may be located in the world anywhere, service provider can make use of these
hardware resources and provide quality of service to the customers.
IV.Software Defined Networking:
SDN: Software Defined Networking is a function to computer networking that allows network administrators to govern
network services through abstraction of lower-level purpose. SDN is meant to respond to the fact that the static
formation of conventional networks doesn't support the dynamic, scalable computing and storage needs of more
radical computing environments such as data centres. This is done by demerging or disassociating the system that
makes decisions about where traffic is sent (the control plane) from the lurking systems that forward traffic to the
selected destination i.e. the data plane.[6],[7]
Types of SDN are as follows.
Shallow and Deep SDN:
In this form of SDN, a virtual overlap network is created between vSwitches- virtual switches. The traffic
paths between vSwitches run over a traditional routed/switched network, or perhaps a switched fabric
network. Because it depends on vSwitches as the overlap network endpoints, it is primarily a data centre
SDN solution.
Deep SDN is a method of controlling packet forwarding behaviour, one that can perform policy routing
without complex combinations of protocols, as is required in shallow SDN. The logically centralized
controller is able to see the entire network topology and make smarter decisions about the paths to use for
each traffic type
Table2: Comparison of SDN and NFV considering different features as given in the table below.
Features SDN NFV
Focus or major
role SDN focuses on data center. NFV focuses on service providers or
operators.
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Strategy It splits the control and data
forwarding planes.
It replaces hardware network devices
with software.
protocol Uses OpenFlow Not finalized yet, does support
OpenFlow
Where the
applications will
run?
Applications run on industry
standard servers or switches
Applications run on industry standard
servers
Prime intiative
supporters
Vendors of enterprise networking
software and hardware.
Telecom service providers or
operators.
Business
initiator Corporate IT Service provider
Customer benefit
or end user
benefit
Drives down complexity and cost
and increases agility.
Drives down complexity and cost and
increases agility.
Initial
applications
Cloud orchestration and
networking
routers, firewalls, gateways, CDN,
WAN accelerators, SLA assurance
Formalization
body
Open Networking Foundation
(ONF) ETSI NFV Working Group
Figure (2) Architecture of Hypervisor
The hypervisor is a software program which can host number of virtual machines as shown in the figure above. The
network function virtualization is a traditional approach of virtualization. As shown in the figure (2), hypervisor can
create, control and manage the multiple virtual machines. Each virtual machine is an independent entity with virtual
SMSCs, virtual MSCs or virtual HLRs. These virtual machines have their own libraries, guest operating systems and
virtual storage spaces. If one virtual machines consumes its storage space then it is not allowed to take storage of
adjacent machine. The hypervisor is based on single host operating system, one server and one RAM. This enables
virtualization, provides complete isolation among virtual machines and distributes hardware resources of the host.
Science, Technology and Development
Volume X Issue VIII AUGUST 2021
ISSN : 0950-0707
Page No : 183