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V.     references

Irrespective of the
current trends of virtualization in every aspect of cloud computing and internet
protocols, network virtualization stands unique from the virtualization design
space point of view. As it is necessary to have a virtualized network in order
to set an inter-connection between all other virtual networks, it is also
crucial to enhance the rapidity of internet and networking that is seeing a
slow paced activity because of the huge population of multiuser support system.
Most current researchers think that a redesign is a necessity and not a luxury.
NV can take a stand point and leadership in the field of cloud computing to
promote innovation, flexibility and heterogeneity. This realization has led to
the rise of innumerable projects across the globe related to NV. Moreover, realizing
the actual extent of NV needs to satisfy the requirements and objectives set by
its designated goals. Although ensuring these shall give rise to a flexible and
heterogeneous networking environment, attaining these is difficult.

IV.     conclusion

Pre-deployment phenomena
includes the geographical distribution of networking services that is typically
designated and assessed in test labs under controlled environment and these
tests are limited to simple topologies and traffic patterns.

3.7 
Experimental and
deployment facility

This concept should reign
on the underlying networking technologies as well as on end to end virtual
networking to provide a wide array of topologies to the users.

3.6 
Heterogeneity

Programmability of the
network elements is crucial to give birth to a flexible and manageable VN.

3.5 
Programmability

These should be provided
by the NV to prevent any mishaps resilient to faults and attacks.

3.4 
Isolation, security and
privacy

NV should always motivate
the coexistence of multiple networks over the same physical substratum in order
to provide multiple virtual networks for the underlying infrastructure to
manage resources (Addanki et al,.
2017).

3.3 
Scalability

 

NV should separate SPs
from InPs to modulate and manage tasks to introduce accountability in
networking

3.2 
Manageability

Crucial for NV in order to
provide SPs stage to use arbitrary topologies

3.1 
Flexibility

Enabling of multiple
analogous virtual networks to cohabit together has a set goal on a shared
physical substratum that can be categorized into several smaller objectives. In
order to bring these to action, each of these designated goals must be
fulfilled to the brim. These goals helps in providing a guideline in the
designation of a protocol or an algorithm for virtual networks and can also be
used to compare multiple NV schemes

3.     
Design Goals

An edge Ev in the virtual
network spans over one or more connected physical links in the underlying
physical topology.

2.5 
Virtual link

It can either be a virtual
host or a router all on its own.The former act as a packet source and cannot be
found inside the network whereas the virtual router acts in a way similar to
the router in the physical network. Its main application is to forward packets
in accordance to the protocols generated.

2.4 
Virtual Node

Another weighted
undirected graph Gv=(Vv, Ev) where Vv is the set of virtual nodes and Ev the
virtual links (Sunay et al,. 2017)

2.3 
Virtual topology

 

 

 

It is designated by a
weighted undirect graph Gp = (Vp, Ep), where each node in the network is
vertex.

2.2 
Physical topology

This section defines the
commonly used terminologies and notations frequently appearing while describing
or referring to the different aspects of a NV architecture.

2.1 
Concepts

The basic entity of an NVE
is the virtual network or VN and each one of these are made up of and managed
by a single SP. It is nothing else but a collective assembly of virtual nodes
connected together by a set of virtual links forming a virtual topology. Fig. 2
(Zhang et al,. 2017) designates two
analogous virtual networks VN1 and VN2 created by service providers SP1 and SP2
respectively. The former composed VN1 on top of the physical resources which
were managed by two different infrastructure providers InP1 and InP2, providing
end to end users U2 and U3. The latter, on the other hand, had a deployment of
VN2 by combining resources from InP1, with a child virtual network from SP1.
End users U1 and U3 have been well connected by VN2.

2.     
Architecture

They play an important
role in the network virtualization economy, acting as mediators between InPs,
Sps and end users in the network virtualization marketplace. Sps lease the
resources from InPs to create virtual networks of all sort and deployment of
sold services to these virtual networks to interested end users through
brokers. The presence of brokers makes it easier for the matching processes of
SPs’ requirements to available resources by accumulating offers from multiple
InpS and also helps by allowing end users in selecting desirable services from
a wide range of SPs.

1.4 
Broker

As far as the network virtualization
is concerned, end users are similar to the end users in the already prevailing
internet, with an exception of multiple virtual user existence from competing
SPs that leads to the enabling of choices from a wide range of services. Any
end user may feel free to get connected to a multiple service provider for
different services (Jiang et al,.
2017).

1.3 
End user

Service providers or SPs
give off resources from multiple facilities providers in order to create
virtual network while deploying customized protocols by programming the
requisite networking resources to offer end to end services to the end users.
Child virtual networks can also be created by an SP by partitioning its
resources. After that, lease of those child networks can be provided to other
service providers, thereby taking a practical role of an infrastructural
provider creating a hierarchy of roles (Fig. 1b) (Kitindi et al,. 2017).

1.2 
Service Provider

Infrastructure providers
or InPs engages and manages the underlying physical network resources in the
NVE. They forms the baseline for managing, operating and maintaining the
physical infrastructure and resources through programmable interface to
different ISPs. No direct services are provide to the end users. Infrastructure
providers make themselves unique in the way of quality of resources that is
provided, the freedom and tools being imparted to their customers or service
providers.

1.1 
Infrastructure Provider

The NV model players or
investors (Fig. 1a) (Kitindi et al,. 2017)
varies from those in the traditional networking model. There lies the presence
of two distinctive roles: infrastructure
providers and service providers,
represented by a single role; ISP in the conventional model. Looking from a
commercial point of view, this decoupling phenomena reduces high fixed cost of
maintenance that is a result of sharing capital and operational expenditures
across multiple infrastructure providers. Emphasis should also be put on
business roles that do not necessarily join one to one distinct business
entities which means that any business entity can assume multiple roles.

1.     
Reference Business Model

The pluralist approach defines
network virtualization as a crucial part of the diversified internet
architecture that helps in supporting multiple cohabiting networking
architectures from different ISPs that shares a common physical matrix or
support. These are managed by a multiple infrastructure providers. By the
phenomenon of decoupling ISPs from infrastructure providers, NV sets forth
flexibility for innovation and change. This section deals with a
conceptualistic approach of the NV architecture in accordance with a reference
business model and identifies the main designating factors to materialize the
architecture

III.     network virtualization
environment (NVE)

Routing Service Providers
(RSPs) are introduced as third parties by the “Routing as a Service” (Abdelaziz
et al,. 2017)in buying virtual links
from different ASes connecting a number of virtual routers. Hosts who desire a
customized route may contact with an RSP for a contract establishment, thereby
setting up an end to end overlay path along its virtual links corresponding to
the global topology. OverQoS sets a stage for giving ample information
regarding to establish overlay links with certain loss and delay gurantees (Addanki
et al,. 2017). Provision of value
added internet services is achieved by the use of Service Overlay Network (SON)
(Kitindi et al,. 2017) and it can
purchase bandwidth of up to certain QoS guarantees from different ISPs  in order to construct a logical end to end
service delivery overlay.

The Detour study (Fietz  et al,.
2016) has shown that the re-routing packets had been found useful in improving
end to end performance via virtual tunneling, in terms of loss, latency and
throughput compared to the direct internet path. The Resilient Overlay Network
(RON) (Gross and Davie, 2016; Narten et
al,. 2016) project experimentally determined the fact that an overlay
network that works on its own networking measurements recovers faster from
failure with an enhance in latency.The overlay-based Internet Indirection
Infrastructure (i3) (Black et al,.
2016) makes it a point to simplify the network services’ deployment and
management services by decoupling sending and receiving. In i3, packets are
been sent from the sources to a logical identifier while the recipient express
interest in packets that is sent to the identifier. This level of indirection
enhances flexibility in node mobility and deployment. In all the three cases,
routing performance of the internet is wired by an overlay on top of the
existing matrix.

Consequentially,
deployment of new features and fixes in the internet has long been approached
by the use of overlay network. A wide array overlay networks have been proposed
in the recent years to mitigate several diverse issues including performance
insurance (Low et al,. 2017) and
availability of internet routing (Gross and Davie, 2016), enabling
multicasting, providing QoS guarantees, protection from denial of service
attacks and for content distribution, file sharing and storage systems (Sunay et al,. 2017).

This is a kind of virtual
computer network creating a virtual topology on top of the physical topology of
another network. Virtual links connect the nodes in an overlay network
corresponding to a path that is again connected by multiple physical links in
the underlying network. Overlay network is not governed geographically and such
restrictions does not follow suit and the involvement is completely
intentional. Because of the fact several participants share their resources to
the network, hence it does not pay overlay a heavy expenditure. Moreover,
compared to other networks, they are highly flexible and adaptable.

1.     
Overlay Networks

Multiple co-inhabiting networks is
not new to the world of cloud computing and internet and has been reported
several times earlier in the literatures related to networking. This section
emphasizes on the most widely accepted incarnation of network virtualization,
that is, overlay networks. An overlay network is a kind of virtual network that
finds use in the application layer in addition to the existence of several
implementations in the lower layers of the networking protocols. Although weak,
it has been widely used to bring in new features and fixes in the internet.

II.     historical perspective

This report assesses the former and
current state of the art technologies in network virtualization while
identifying its key prospects.

Although network visualization has
been considered as a stage to assess new architectural advances by the purists,
pluralist approaches consider it as a support system for the architecture
itself (Blenk et al,. 2016). They
think that network virtualization has the capability to extenuate the
tremendous forces of the current internet and enhance innovative approaches by
enabling diverse array of networking architectures to coexist on a shared
matrix. Policy separation from mechanism is crucial in order to introduce
diversity in computing field, and such examples have been set by networking virtualizations
(Gross and Davie, 2016; Khan et al,. 2016).
The role of the ever-changing ISPs has been sub-divided into two categories: infrastructure providers, responsible
for managing the physical infrastructure, and service providers, responsible for creating virtual networks by
accumulating resources from multiple infrastructure providers thereby offering
end-to-end encryption to the users. This scenario shall encourage the
deployment of multiple cohabiting heterogeneous network architecture unbound by
the inherent restrictions found in the existing internet.

The way of life, our thinking attitudes, modulations towards the society
and virtual proliferation has been widely influenced by the internet and this
has mended the way more smoothly for the development of the human race as a
whole. The extent of the internet architectural plethora and influence has been
proven universally over the last three decades by the active support on a
platform of multi-various applications and technologies over which it currently
thrives. But, its popularity has become its toughest enemy. Because of the
presence of a huge population of users and its multi-provider nature, adoption
of any new technology to enhance the existing one will invite strong
competition among the investors. Hence, modifications of the internet
architecture have been limited to only incremental updates without making any
considerable changes by the introduction or deployment of new networking
technologies (Gross and Davie, 2016).

I.     INTRODUCTION

 

Keywords:Internet, network virtualization, cloud computing,
flexibility, versatility.

 

Abstract—Networking, currently have faced
several potholes, due to the presence of multiple investors having differences
of opinions, due to which, changes in the existing internet have now been
restricted only to incremental apprises; and overall disposition of fresh
technological aspects is completely impossible in this field. In order to
mitigate these restrictive issues, network virtualization has been identified
as the next generation penicillin that shall contribute to the future of cloud
computing and inter-networking prototype. Network virtualization allows the
coexistence of multiple heterogeneous network architectures on a shared matrix,
thereby providing flexibility and versatility with increased security and
manageability. The current report deals with the pros and cons of network
virtualization in accordance to the set goals, past surveys and state of the
art technological advances and also discusses the future challenges and scopes
that require proper identity.