Final Dissertation

A Critical Analysis of Virtual Desktop Infrastructure and its
Application in Enterprise.
Title Page:
Name: Matthew Binder
Supervisor: Anthony J H Simons
Module Code: COM3600
Project Code: AJHS-UG-9
About: This report is submitted in partial fulfilment of the requirement for the degree of
Information Technology Management for Business by Matthew Binder.

Signed Declaration:
All sentences or passages quotes in this report from other peoples work have been
specifically acknowledged by clear cross-referencing to author, work and page(s). Any
illustrations which are not the work of the author of this report have been used with the
explicit permission of the originator and are specifically acknowledged. I understand
that failure to do this amounts to plagiarism and will be considered grounds for failure
in this project and degree examination as a whole.
Name: Matt Binder
Signature:
Date:

Abstract:
The rise of the ‘as a service’ business model for computing has opened the Virtual
Desktop Infrastructure (VDI) market to both public and private sector organisations.
Rather than building a complex VDI network, the infrastructure can be outsourced to a
3rd party solution provider. This is known as Desktop as a Service (DaaS). Amazon;
Citrix; VMware and Microsoft are some of the market leaders in the industry to be
evaluated throughout this report. Each service provider offers fully managed and
supported desktops. But which Windows desktop performs to the highest standard,
offering the most advantages to a user and enterprise.
The aim of this report is to investigate each of the DaaS providers highlighted above,
aiming to critically compare and evaluate their individual service offerings.
Their environments will be applied to a number of business use cases to see if DaaS
could viably replace their Windows desktop delivery strategy.

Acknowledgements:
I would like to start by thanking the various partners that I have been working with
throughout this project. Without their support and willingness to help and share their
knowledge I would have had no dissertation project. (At one point this was a genuine
worry) The individuals and companies that I would like to thank particularly include:
 Kade Hoff and Taylor Cherry from PRG Technology Solutions.
 Imran Rashid from Molten Technologies.
 Duncan Little and Mark Curry from BrightCloud.
All of these individuals took time to work with me on this project for no commercial
benefit to their business. I am extremely grateful for this, and as a result have developed
a strong professional network of contacts within the VDI and DaaS industry.
I want to thank my supervisor Anthony Simons for opting to support me on this project
with little prior knowledge of the subject area. I truly enjoyed sharing this journey into
the world of cloud-hosted desktops and the advice you gave me.
Last but by no means least I need to thank Emily Green and my family for their on-going
support.
This dissertation was supported by an AWS in Education Research Grant award.

Table of Contents
A Critical Analysis of Virtual Desktop Infrastructure and its Application in
Enterprise................................................................................................................................
Title Page:..........................................................................................................................................
Signed Declaration:........................................................................................................................
Abstract:.............................................................................................................................................
Acknowledgements: ......................................................................................................................
1: Introduction: ............................................................................................................................1
1.1 Project Background:......................................................................................................................1
1.2 Motivation: ........................................................................................................................................1
1.3 Aim: ......................................................................................................................................................1
1.4 Potential Constraints: ...................................................................................................................2
2: Literature Survey:...................................................................................................................3
2.1 Server Virtualization to Desktop Virtualization:...............................................................3
2.2 Other Desktop Virtualization Alternatives:............................................................................6
2.3 Components of a VDI Implementation: .................................................................................7
2.4 Potential Benefits of VDI to an Organisation: .................................................................. 15
2.5 Potential Drawbacks of VDI:..................................................................................................... 16
2.6 Why VDI Projects Fail:................................................................................................................. 16
2.7 The Evolution of Computing: From Mainframe to Cloud............................................ 17
2.8 Cloud Computing:........................................................................................................................ 19
2.9 The future of VDI? Desktop as a Service (DaaS)................................................................ 19
2.10 Benefits of DaaS:......................................................................................................................... 20
2.11 Drawbacks of DaaS:................................................................................................................... 21
3. Technology Review: ............................................................................................................23
3.1 Amazon Workspaces:................................................................................................................. 23
3.2 VMware:........................................................................................................................................... 24
3.3 Citrix:................................................................................................................................................. 26
3.4 Microsoft Azure: RemoteApp.................................................................................................. 27
4. Requirements and Analysis: ............................................................................................28
4.1 Ethics:............................................................................................................................................... 28
4.2 Initial Analysis:............................................................................................................................. 28
4.3 Detailed Requirements: ............................................................................................................ 28
5. Design:......................................................................................................................................33
5.1 DaaS Environments Test Case Design:................................................................................ 33
5.2 Enterprise Case Studies for moving to DaaS .................................................................... 40
6. Results and Discussion: .....................................................................................................43
6.1 Comparison and Evaluation Document.............................................................................. 43
6.2 Test Case Results ......................................................................................................................... 43
6.3 Enterprise Viability of Moving to DaaS:.............................................................................. 52
6.4 Completed Requirements: ....................................................................................................... 54
6.5 Further Work: ............................................................................................................................... 54
7. Conclusions:...........................................................................................................................56
References:...................................................................................................................................58
Appendices: .................................................................................................................................69

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1: Introduction:
1.1 Project Background:
Last year whilst on placement with GE Oil & Gas the author first gained exposure to
Virtual Desktop Infrastructure (VDI) and the GE business strategy from project leaders,
as well as practical experience using, deploying, and maintaining the solution for
targeted users.
VDI is defined as the practice of running an operating system (OS) within a virtual
machine (VM) hosted in a data centre. This means that while living in the GE private
cloud: the desktop, applications, and, settings were hosted in a centralized London data
centre. These are accessible with a network connection from a supported client device.
Before returning to university there was a strategic shift moving away from the inbuilt
VDI and research began into the benefits of 3rd party hosted VDI solutions known as
Desktop as a Service (DaaS). DaaS takes the entire infrastructure required to implement
hosted virtual desktops placing it under the control of a cloud service provider.
1.2 Motivation:
The potential merits of VDI were apparent to the organisation. However various
problems caused the solution to be viewed negatively by users. VDI eventually became
a scapegoat for other internal IT problems. VDI has the potential to improve an
organisation’s security and mobility combined with a movement towards the cloud also
adding further scalability and flexibility as well as a desirable cost model.
The VDI and DaaS industry is maturing year on year, with analysts claiming, “This is the
year of VDI”. But how accurate are these assertions? Will VDI ever replace the traditional
standalone desktop PC in the workplace? Or are VDI and DaaS only viable for specific
use cases.
1.3 Aim:
The goal of this project is to critically compare and evaluate the DaaS offerings from the
market leaders in the industry namely:
 Amazon Workspaces
 VMware Horizon Air
 Citrix DaaS
 Microsoft Remote.App
Although these providers are offering similar services, they each have different
approaches, features and benefits. Part of the analysis will form an evaluation document
comparing each of these solutions in terms of their features and merits, advantages and
disadvantages.
This document will help inform my analysis of which service provider offers the best
environment. These findings will be shared with each supporting company and
published online for the benefit of other members of the maturing VDI and DaaS
community.
DaaS, unlike VDI, is more attainable for all sizes of enterprise, ranging from corporate to
small organisations. The analysis will highlight the way in which companies from each
of the following three levels differ in IT requirements and the potential viability of a
DaaS solution in each case.

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The companies are broadly segmented into three different categories:
 Small – Less than 50 employees.
 Medium – Less than 250 employees.
 Corporate - Greater than 250 employees.
Each environment will also be evaluated against relevant test cases and performance
benchmarking software to compare each virtual desktop against physical and virtual
desktops. With the ultimate aim of finding which environment performs to the highest
standard and can offer the most benefits to users.
1.4 Potential Constraints:
Implementing a DaaS or VDI solution requires vast amounts of capital and expert
knowledge, which is beyond the scope of this project. For this reason only commercially
available solutions targeting enterprise are included. As a result the evaluation criteria
will focus on the potential benefits to an organisation.
Some providers only engage with customers who are looking to access 50 desktops as a
minimum. Ideally solutions from all three-service providers will be analysed and
evaluated. However much of the success of this will rely upon gaining sponsorship from
the companies previously mentioned in 1.3.
Using businesses of varying sizes in my report to analyse the viability of moving towards
a DaaS solution is relevant on their support. Ideally a test environment would be
created, complete with all the relevant application software. However the practicalities
of this without any financial backing are limited. This will not detract from the analysis
and recommendations, though further work would have to be done to ensure the
enterprise requirements are met.
Businesses are non homogeneous, and whilst this project targets businesses of different
sizes, the requirements differ depending on the actual business and relevant markets.
Regardless the findings will help reference whether DaaS can be used to replace fat
client desktops PCs.
1.5 Summary:
The remainder of my report is divided up into the following sections: literature survey;
technology review; requirements analysis; designs; results and discussion; and finally
conclusions.
The bibliography and appendix are located at the end of the document and are
referenced in the Harvard manner.

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2: Literature Survey:
This chapter includes in-depth information on VDI and DaaS from various academic and
industry experts. The purpose of this chapter is to give the reader an understanding of
VDI and the components of an implementation. It will also cover cloud hosted VDI –
otherwise called DaaS - which will be the focus for this dissertation.
2.1 Server Virtualization to Desktop Virtualization:
Virtualization is the creation of a virtual resource rather than physical. Originating from
the rise of mainframe computing and the idea of developing robust ‘time-sharing
solutions’ that proportion the usage of computer resources to a large group of users.
Increasing efficiency and performance for the users and the underlying computing
resource (Oracle, 2012). The motivation for virtualization projects today is looking to
use available resources more effectively so as to save money and increase efficiency.
Server Virtualization is defined as the masking of server resources, such as: volume,
identity, operating system and processors from other server users. This allows the
physical hardware to be partitioned into multiple isolated virtual environments. These
virtual partitions are commonly referred to as guests, with the underlying hardware
being the host (Bigelow, 2009a).
Figure 1:Graphic demonstrating a virtualised computing resource (Nash Networks, 2009).
There are three primary approaches to server virtualization. These are: virtualization at
the operating system (OS) level; paravirtual machine model; and the most relevant to be
covered in this report on VDI, the virtual machine model (Rouse, 2009).
Within the virtual machine model of virtualization each guest is running upon imitation
simulated dedicated hardware. This gives the illusion of complete independent access
to the underlying hosts resources. In reality, the resources are being shared between
different guest virtual machines using software called a hypervisor to emulate resources
like CPU, memory, and network. A virtual machine is similar to a physical computer
capable of running an operating system and applications (Matlis, 2006). The difference
being there is no physical hardware attached.

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The main choice for enterprises regarding virtual machines is either stateful or stateless,
otherwise known as persistent or non-persistent. A stateful VM enables users to have
their very own personal disk image (Madden, 2007). This comes with the additional
requirement of backend storage, however users have their own customized
configuration of a VM. This is most commonly used when applications and data need to
be accessible in the same state, even when a VM has been killed by the user logging off
from Windows.
In contrast, stateless virtual machines separate the OS from the users data. All users in
this instance can access the same configuration of virtual machines, which are collected
together into pools of aggregated computer hardware (Rouse, 2012a). These pools
group VM’s together based on identical configurations and access to physical compute
hardware such as CPU and memory. When a user makes changes to the VM
environment once they kill the session the VM resets, with all the changes being lost.
Data and applications rather than being contained within the VM can still be stored and
associated to a user profile. However, they have to be stored on separate hardware such
as a network share then assigned to the VM at logon (Evans, 2012a).
Stateless VMs are useful in deployments where users access the same core
configuration. This is achieved using a ‘gold image’ template for VM’s that share the
same disk image, applications and configurations. User in this instance can share the
same VM image from a pool of repeated desktops (VMware, 2014a).
Server virtualization continues to have a huge impact throughout enterprises as cost
savings can be made through server consolidation projects. This enables more efficient
use of data centre space, less hardware purchases, with reductions in power and cooling
bills. This creates appealing use cases for enterprises to move from traditional to virtual
server architectures (Golden, 2008). A virtual server is more desirable as it can be
migrated from one host to another, on any server hardware without worrying about
specific drivers and software.
Figure 2: Move from traditional to virtual architectures (VMware, 2015).
Before Desktop Virtualization came Server Based Computing (SBC) when in 1990 Citrix
Systems started using the idea of users viewing a remote image of a program that was
being forwarded from a server where the application was running (Madden, 2009).
This software was first made commercially available with the release of WinFrame. This
allowed a server to provide windows applications and data to an attached workstation
(Rouse, 2005).

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Desktop virtualization is the concept of isolating the operating system from the client
used to access it (Madden, 2011a). This is different to the definition of VDI, which refers
to the basic architecture for desktop virtualization with a virtual machine running on a
remote server (Knoor, 2010). Desktop Virtualization encompasses the use of software
to extract the OS, applications and data from a PC.
Within the industry Microsoft had observed what Citrix was trying to achieve with
WinFrame. It began collaborating to release the first version of Terminal Server, later
renamed Remote Desktop Services (RDS). RDS allows users to take control of a PC over a
network connection. From the server perspective it bought the ability to host multiple
simultaneous client sessions all running on Windows Server OS.
VMware had become the market leader for server virtualization with its technology
being applied ubiquitously throughout the industry. Citrix was also very successful with
its SBC offering for RDS. In 2006 VMware started utilizing its expertise to apply
virtualization techniques to desktops (Knuth et al 2013).
VMware took a different approach to Microsoft and Citrix whose software products
relied upon installing a special version of Windows Server. This data centre copy of
Windows allows for multiple users to simultaneously access the same copy of Windows
Server (Knuth et al, 2013). This meant that thousands of desktops could be supported
by one server. However, the user was limited to using the server based OS and server
compatible applications, rather than the full compatibility of a client OS.
The VMware strategy was to target the desktop OS and host this remotely in the data
centre giving users access to their normal working environment with complete
application support. The downside compared to the Citrix solution was that it required
much more hardware to support the same amount of users. This product they named
VDI to differentiate away from SBC. VDI takes the technology from desktop
virtualization and places operating systems into hosted VMs running on a server in a
centralized data centre.
RDS and VDI both host windows desktops in the data centre. The main difference is that
users of RDS access a shared VM, whereas VDI users gain access to dedicated VM’s. The
VDI VM is isolated, running an independent OS compared to the RDS solution in which
users access a VM that is executing a shared same server OS.

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Figure 3: VDI vs. SBC (Turbotek, 2011)
2.2 Other Desktop Virtualization Alternatives:
RDS and different forms of VDI currently dominate the desktop virtualization market for
hosting windows computers on servers. However, there are less popular alternatives
available.
Offline VDI / Client Hypervisor: Offline VDI offers similar benefits to VDI but does not
require a network connection to the data centre. The virtualization software is instead
installed directly onto the client device, leaving the VM to be executed on the PC rather
than in the data centre (Strohmeyer, 2012). Offline VDI is achieved using either Type 1
or Type 2 Virtual Machines. These are extremely similar to the Hypervisors used in the
server infrastructure to achieve virtualization. In this instance a Type 1 virtual machine
is client based known as “bare metal” as the Hypervisor is the direct OS. Type 2 VM’s
are more common with the guest VM running on top of the existing OS (Knuth et al,
2011).
OS Streaming: OS Streaming differs from traditional desktop virtualization, as the
hypervisor is not required. OS Streaming involves an operating system being run from a
server and streamed to a client’s device as required. The desktop device boots
mounting the disk image over the network, rather than from hard disk (Madden,
2010a). This is mainly used in configurations where by removing the hard drive from a
PC is of a huge benefit. This technology reaps some of the advantages of VDI with
improved security in the consolidation of devices. Users can share one centralized disk
image that can be updated and patched as required (without a technician physically
touching a PC). One requirement that comes with OS streaming is a high speed wired
Internet connection, as it requires a constant Internet connection without any drops in
connectivity.
Application Streaming: Application streaming is a form of on demand software
distribution in which software is delivered over a network. This is possible, as most
applications only require a small portion of the code to run. It is these portions of the
application code that need installing onto the client device or computer. The remaining
code is then delivered over the network as it is requested and required. This is more of

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a complimentary technology to be used alongside desktop virtualization becoming
popularized with the rise of Software as a Service (SaaS) and cloud providers.
Traditional ‘Desktop’: Traditional desktop PCs still make up the vast majority of
computer resources in enterprise and public use. The reason for this is that
virtualization should only be used to target specific use cases, or else some of the
problems of VDI will become apparent. This will be discussed later on in the report.
2.3 Components of a VDI Implementation:
2.3.1 Storage:
One key consideration for any VDI project is the storage required for the
implementation. VDI is not ideal for traditional storage methods as the volume of
random IOPS (input outputs per second) is so high. This needs to be considered
alongside factors such as: the read/write penalty on storage as VDI is writing up to 80%
compared to only 20% read time; the read/write ratio of applications running inside a
Virtual Machine; and, the possible latency involved in different storage platforms
(PureStorage, 2014).
VDI performance can often struggle to deal with high demands of input/output spikes.
One example of these spikes in performance are ‘boot storms’ (Siebert, 2011). A boot
storm occurs when many users power on a virtual machine at roughly the same time.
This has implications for general network performance, storage input outputs and host
server performance. However this kind of performance impairment is not just isolated
to boot. Troughs and spikes can occur during anti virus scans, logins and application
launches (VBridge, 2014). Therefore selecting the most appropriate storage is essential
to performance and subsequently end user satisfaction.
Some of the storage options are listed below:
Serial Attached Small Computer Systems Interface (SAS): SAS is a serial method for data
transfers which allows for one bit at a time (Rouse, 2006a). Commonly used in disk
drives and tape decks it is not well suited to VDI due to the limitations placed on
performance of the constrained storage.
Solid State Disks (SSD): SSD solutions can be used within VDI to improve performance by
using the persistent data on solid-state flash memory. SSD performs well as there is a
lower random and read access latency than HDD’s. This allows for greater performance
and seeks to reduce some of the problems posed by boot storms. SSD’s do have some
disadvantages though; they only have a set number of write cycles before performance
is reduced (Rouse, 2014a).

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Figure 4: Comparison of SAS vs. SSD Boot Times (Samsung, 2013).
SAN: Storage Area Network is a dedicated high speed fibre network interconnecting and
sharing pools of storage to multiple servers (Rouse, 2014b). This has great implications
for VDI as this storage has high performance and availability with no limits to expansion.
(Evans, 2012b) There have also been recent developments into Virtual SAN’s, which
allow for aggregation of SSD and HDD across a network to create an improved
performance for VDI users (Dilkie, 2014).
NAS: Network Attached Storage is a single dedicated file storage device that provides
LAN users with centralized, consolidated disk storage (Rouse, 2014c).
SAN vs. NAS for VDI: The main difference between NAS and SAN solutions is the type of
access protocol with NAS offering file level protocols and SAN offering block level
protocols. It depends upon the individual VDI implementation as to which is more
desirable. However, they can always be combined into a shared solution (ISCSI, 2014).
The storage battle with VDI is on-going. If the project is expanding the number of users
and desktops being provisioned, this means that storage needs to be expandable to
cope. One of the problems is that storage is one of the most expensive aspects of a VDI
implementation. Yet without high performing storage the end user performance is
greatly restricted. The more input/outputs the greater strain on VDI storage.
2.3.2 Hypervisors:
A hypervisor is a thin layer of software that desktop virtualization heavily relies upon.
This software is a Virtual Machine Manger that allows for multiple systems to
concurrently share a single hardware processor. Each operating system appears to have
dedicated use of the CPU, memory, GPU and other hardware (How to Geek, 2011).
However in reality the hypervisor is allocating resources in turn (Rouse, 2006b). The
hypervisor enables VMs to appear as though they have dedicated access to hardware
resources.
There are a two of types of hypervisors commonly used throughout enterprise:

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Type 1: A type 1 hypervisor is called ‘bare-metal’ as the operating system is installed
directly onto the server. The benefit being that the hypervisor will communicate
directly with the underlying hardware (Kleyman, 2012).
Figure 5: Type 1 Hypervisor Diagram (DataCenterKnowledge, 2012)
Type 2: Alternatively a Type 2 is not bare-metal and sits directly on top of an already
installed operating system. This type of hypervisor creates virtual machine
environments and coordinates calls for CPU, memory, disk, and network (Rouse,
2012b).
Figure 6: Type 2 Hypervisor Diagram (DataCenterKnowledge, 2012).
Increasingly the trend is moving towards type 1 hypervisors, as organizations can
purchase servers with an attached hypervisor, then install an OS of preference, rather
than purchasing a server with a preinstalled OS (Desai et al, 2013).

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2.3.3 Connection Broker:
Connection Brokers are another important component of any VDI network. Described
as a “traffic cop, directing incoming connection requests to available hosted desktops.”
(Lowe, 2007). Connection Brokers align users and back-end resources together and are
responsible for ensuring users receive the correct VM. It also performs other actions
alongside this, such as user authentication by assigning user to hosted desktops based
on a predefined policy or group membership (Sturdevant, 2010a).
The Connection Broker also includes management functions such as the ability to power
on and off VM’s, and suspend and resume VM’s. There are also useful tools for network
administrators who are able to view all current connections to desktops so there is
accountability for who is assigned to which desktop. Administrators can also create and
manage new pools of virtual machines.
Network Connectivity is something dealt with by Connection Brokers in two different
ways. ‘In-line’ brokers allow all connection traffic to flow through the broker to reach
the hosted operating system (Lowe, 2007). This means that the traffic can be routed
through a Virtual Private Network (VPN) or Quality of Service (QOS). Alternatively, ‘out-
of-band’ brokers do not handle the traffic directly; they simple redirect the client device
onto the hosted OS.
Figure 7: Role of the connection broker (Virtualization.Info, 2010).
2.3.4 Communication / Remote Display Protocols:
The role of remote display protocols in the VDI environment is huge. They are the data
transfer rules responsible for transmitting data from the data centre to the remote
device. This has developed from simply displaying the desktop image to include
functionality for, drive mappings, USB redirection, and multi-monitor support (Wood,
2013. Each different VDI vendor has their own approach to communication protocols.
Although there are similarities across all three of the solutions from Microsoft, VMware
and Citrix. They are all based on the Open Systems Interconnection (OSI) stack layer 4
transport protocols, User Datagram Protocol (UDP) and, Transmission Control Protocol
(TCP).
UDP is a connectionless best effort delivery datagram service. This means it does not
provide full reliability or guarantee the delivery of data units or sequencing of data. The

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data itself is not broken down into packets and reassembled on the client; rather the
application program must ensure the data has arrived in the correct order.
UDP does not establish end-to-end connections between communicating systems.
Instead it is characterized with fast, lightweight, unreliable transportation between
hosts. The advantage of this is that it can offer efficient communication to network
applications that are transmitting very small data units. However it is unreliable in
terms of congestion control and reliability (Microsoft, 2015a).
TCP unlike UDP provides a reliable connection oriented packet delivery service,
guaranteeing the delivery of IP datagrams and ensuring sequencing. TCP receives data
bytes from programs and processes them before grouping into segments and numbering
for sequenced delivery. For this data to be transmitted a session must first be initialized
through a three-way handshake. Once the hand-shake has been initiated segments are
then sent and acknowledged (Microsoft, 2015b).
Figure 8: Comparison of UDP vs. TCP (Microsoft, 2005).
Remote Desktop Protocol (RDP) is Microsoft’s secure network communications protocol
for Windows application running on a server. Terminal Services relies upon RDP to
transfer screen information and user interaction to and from the server to client. It
allows for remote desktops and terminal service access to remote users, encapsulating
and passing the data using TCP/IP.
Figure 9: RDP communication (Microsoft, 2014).
RemoteFX is a set of protocols designed for RDP to deliver visually improved Windows
virtual desktops over a LAN. It is comparable to PCoIP and HDX as it includes
functionality for USB redirection, and GPU virtualization on the server side. This allows
for the use of more graphically intense applications (Botelho, 2012).

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PCoIP is a remote display protocol designed by Teradici for delivering applications and
desktops over a network. The protocol delivers bitmap images by encoding them on the
host and streaming them to the client. This works by only transmitting the regions of
the screen that change from frame to frame. PCoIP is capable of delivering multimedia
and graphically intensive applications although the CPU load will be greatly increased
on the server side (Teradici, 2014).
This is achieved using RDP, which is more concerned with the speed of data transfer,
making multimedia more viable. It does however require host rendering to decode the
transmitted data to eliminate display latency on the client. PCoIP is ideal for thin and
zero clients with many being designed exactly for this purpose.
Figure 10: Example PCoIP Client Network (CNXSoft, 2012).
High Definition Experience (HDX) is Citrix TCP/IP brand for optimizing the remote
desktop vitalization experience. HDX was developed from its original Independent
Computing Architecture (ICA) protocol to encapsulate several different Citrix
technologies. These technologies are designed to: optimize the user experience;
decrease bandwidth consumption; and increase scalability on the host server. ICA itself
is a protocol for passing data, such as keyboard and mouse inputs, from server to clients.
This is achieved using virtual channels.
Figure 11: Cross section of virtual channels. (Gołębiowski, 2013)

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2.3.5 VDI End User Client Delivery:
As VDI isolates the operating system from the hardware required, this opens up new
options for client machines rather than simple desktop and laptop computers that
currently dominate enterprise.
Thin Client: Thin Clients are low cost, centrally managed computers that are often
devoid of: hard drives; CD-ROMs; disk drives and expansion slots. A thin client relies
upon the external server for computation only displaying the results (Maga et al, 2013).
Typical features of a normal PC are stored in the data centre when using a thin client.
These include applications, data and memory. Thin devices tend to have a: CPU; flash
memory; local storage and local operating system installed. This gives access to a
Connection Broker in order to provision virtual machine access. Thin clients are
becoming increasingly popular as enterprise moves towards cloud computing and
organisations are looking to reap security, manageability and cost benefits that arise
with thin client usage (DevonIT, 2012).
Zero Client: Unlike thin clients, zero clients have no local processor or operating system
installed. In reality, zero and thin clients are very similar but the main difference is that
zero clients require no device management in terms of updates to firmware or
configurations (Madden, 2010b). Zero clients instead of the pre-installed operating
system have a highly tuned processor that is specifically designed for three VDI
protocols (PCoIP, HDX, RemoteFX). The majority of decoding and display processes take
place in the hardware dedicated to rendering pixels onto a users display. This proves to
be effective for graphically intense applications being delivered over VDI rather than
using a standard CPU and GPU as with thin clients (DevonIT, 2013).
Thick Client (PC): Traditional PC’s can be used in order to access VDI environments. All
that is required is client software to be installed onto the PC that links to the Connection
Broker. This does not bring into account any of the security or potential cost saving
benefits seen with zero and thin clients. However cost savings can be made by recycling
old or end of warranty PC’s to be used as VDI clients (Bigelow, 2009b).
Mobile Devices: As VDI isolates the operating system from the underlying hardware
required, it opens up mobile devices to become terminals. Mobile Applications can be
installed to act as portals to the Connection Brokers giving mobile devices access to the
hosted server. However interaction problems can arise when mapping touch
behaviours to typical mouse and keyboard actions of a desktop (Yegulalp, 2014).
2.3.6 Application/ Software Virtualization:
Application Virtualization can be used independently or alongside a VDI solution.
Similar to desktop virtualization the application is isolated from the operating system
they normally run on top of (Ruest, 2008). This reaps advantages such as improved:
portability, manageability and compatibility. (Madden, 2011b) This can be suitable in
enterprise for many reasons. For example deploying legacy software, or allowing for
cross platform usage. Virtualized software can be flexibly delivered to the user either
via remote applications running on a server, or through streaming the application on
demand to an end users computer.
Two of the market leaders for app virtualization include Microsoft’s ‘App-V’ and
VMware’s ‘ThinApp’. The way in which they produce virtualized applications is
discussed below.

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VMware ThinApp: To produce virtualized application ThinApp starts a clean installation
of a Windows OS taking a snapshot of the registry, dynamic link library (DLL) and files
(Sturdevant, 2008). The required software is installed before another snapshot is taken
to observe the changes. ThinApp packages this all together into an executable .msi or
.exe that can be deployed to a client. Deployment methods include hosting on a network
share, or deploying straight to a client machine, whether that be a desktop PC or a thin
client (Sturdevant, 2010b).
Figure 11: VMware process of virtualizing an application (VMware, 2014c).
Microsoft App-V: Microsoft’s application virtualization and application streaming
solution differs vastly from VMware’s ThinApp. Microsoft describes their product as
“transforming applications into centrally managed services that don’t conflict with other
applications” (Windows, 2012). App-V programs are streamed from the centralised
App-V server so users with an Internet connection can stream the application. There
are also cached options for applications so even without a network connection a user
can access their applications (PCWorld, 2012).
Figure 12: Typical App V Implementation (BDS Solutions, 2014).

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In enterprise application virtualization solutions are often combined with the
instillation of software directly onto a ‘gold image’. A gold image is essentially a
template for a virtual machine created by an administrator to set up the computing
environment (Rouse, 2012d). A gold image generally contains the: operating system,
preferences, applications and settings. Applications installed directly onto these images
are generally considered to be a ‘core load’ of the most frequently used (Ohlhorst, 2013).
2.4 Potential Benefits of VDI to an Organisation:
Security: All the processing, data and applications are running from and residing in a
centralised secure data centre. If a thin client offering is being used no data is stored on
the end terminal. This greatly reduces the threat of corporate data being stolen when it
is at rest (Madden et al, 2013). Security strategists for organisations are being
recommended to assume a state of compromise within organisations (Levy, 2013). VDI
offers other benefits if an attack is carried out on a VM. As soon as the virtual machine is
destroyed the threat will be eliminated. VDI also offers superior patch management as it
is centralised and instantly deployable to all VM’s – reducing the response time to
threats and compromises (Davis, 2012).
End User Support: Supporting users that are using a consistent OS image, or slight
variant of a gold image becomes simpler. Administrators know exactly what to expect
when looking at a configuration. Any problems can be solved by resetting the image or
asking the user to log into a different virtual machine. Support can be delivered
remotely without users having to physically touch a machine. Once a problem has been
solved it becomes very easy to note the changes required and replicate them if required.
Management: All management of user desktops can take place from within a centralised
controlled data centre. There is no individual touching of users PC’s to ensure patches
are being updated. It can all be done centrally without user interaction (Warren, 2012).
This reaps all the benefits of centralized management over distributed management
including simple distribution of upgrades and updates, provision of new users, helpdesk
troubleshooting productivity, and remote control (Pano, 2012).
Bring Your Own Device (BYOD): With the desktop being hosted in a data centre new
options for BYOD client devices are available. No data is stored on the end terminals
alleviating many of the risks associated with BYOD campaigns. Organisations remain in
control of the users data (Paloma, 2013).
Access from anywhere: As all the applications, data and settings are stored in a data
centre, and not on local clients, users can access their desktops from any location, be
that at home, work, or whilst travelling. As long as users have access to an Internet
connection they can potentially access their desktop, vastly improving mobility.
Increased Business Agility: With VDI comes the ability to provide new users with access
to desktops, regardless of location increasing the ability to adapt to changing
environments. It is a simple and fast process to scale up or scale down the number of
virtual machines required within a VDI implementation. Agility for business is seen as a
key attribute for maintaining and driving competitive advantage. So a VDI network can
be a perfect tool for supporting a dynamic environment where organisations need to be
flexible and are able to adapt (Clair, 2013).
Green Technology: The power consumption of thin clients and zero clients is greatly
reduced when compared to typical fat clients. Desktop PC’s typically use 400watts
compared to only 15watts for a thin client (Knuth et al, 2013). This kind of saving
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although reduction in power consumption have to be contrasted with increased server
room spend for power and cooling.
2.5 Potential Drawbacks of VDI:
Capital Costs: Creating a VDI network requires purchase of all the required
infrastructure from, servers to client devices, licensing, support, and training. The
capital costs associated with this are huge (SearchVirtualDesktop, 2013). There are also
other hidden costs outside the initial capital expenditure such as increasing storage
capacity. The more a VDI network expands the greater requirements for storage or
performance will be impaired (Whaley, 2013).
Lack of Offline Ability: With desktops now being run from a data centre it is a
requirement for users to have an Internet connection in order to access their
environment. This is a reasonable expectation within organisations offices or work
places, but when travelling or working remotely Internet connection reliability is
inconsistent (Knuth et al 2013). Even if there is an Internet connection available users
will often have to connect via a VPN adding more time to simply access their desktop.
Although in the future the reliability, speed and coverage of mobile Internet hotspots
will be increased (Ofcom, 2014). This remains an issue when comparing VDI solutions
to a traditional desktops or laptops.
Recent developments from vendors allow for offline VDI, as previously this was seen as
a significant barrier to initial uptake (Madden, 2013).
Support: As VDI is becoming increasingly popular the number of vendors offering
tailored solutions is increasing. The support for these solutions is often coming from
niche experts, which means they are rare and expensive. This will decrease in the future
as VDI uptake continues to rise. Currently this is an important issue to consider for an
organisation, as their network needs to be effectively supported with Service Level
Agreements (SLAs) in place.
Graphically Intensive Applications: As previously mentioned with graphically intense
applications there are a great number of packets of data being sent over a network. This
combined with packet loss and latency means graphically intensive applications do not
perform as well as if they had a dedicated high performance device with a special video
card or GPU (Cooke, 2012). This often results in latency when attempting to view 3D
graphics, multimedia, or even use dual monitors.
2.6 Why VDI Projects Fail:
VDI projects are inherently complex and if not implemented correctly can fail to live up
to expectations. Many projects fail to progress past early stages of deployment resulting
in wasted capital investment. This chapter will cover common reasons why VDI projects
might fail.
Change Resisted by Users: Change for end users is not always well received and often
resisted. Especially if they have moved from a desktop PC where they experience very
few problems or latency. This contrasts to a VDI client conversion and experience of
boot storms, or unavailability of applications due to outages. If the users are not
supportive of the change, and do not understand the advantages and underpinning
business strategy then it is no surprise they resist (Unidesk, 2013).
Lacking Storage IOPS: As mentioned the storage component of any VDI network has the
power to make or break the system. Without sufficient storage and the ability to deal

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with increasing input and outputs, performance will be negatively impacted. This is
often not a problem initially in VDI environments when testing and rolling out to niche
use cases. As the scope for the project expands and more users are sharing the same
storage resources the affect can be to cripple and slow down everyone’s performance.
Network Constraints: With VDI every click, key press or pixel change has to be remotely
transmitted to the data centre for processing. The outcome of the action is then sent
back to a user over a network. The end result is a major increase in network traffic that
can result in decreased performance for all users. Bandwidth is a key factor in ensuring
the stability and potential performance of a VDI network (Ohlhurst, 2010).
Impossible to Virtualize an Application: Using tools like App-V or ThinApp to virtualise
applications is not as simple as it sounds. Some applications are simply impossible to
virtualize. If that is the case and it is a business critical application then VDI will
ultimately fail. Application virtualization also requires experts or trained individuals to
attempt to package the application.
Another potential issue is that once an application is virtualized it is isolated and cannot
cross communicate. It is essentially placed it its own bubble, separate from Windows
and other applications. If users require cross application compatibility then application
virtualization within VDI is not the approach to take.
Underestimating the Complexity: VDI is not an out of the box solution. It requires
specialist knowledge, dedicated planning and testing to implement a functional
environment that meets a company’s needs.
Targeting the wrong use cases: VDI shouldn’t be used as a simple PC replacement
strategy. VDI should be used to target only suitable use cases. This is exemplified by
VMware who only use their solution for internal use cases such as remote access, or
testing portals (Knuth et al, 2012).
2.7 The Evolution of Computing: From Mainframe to Cloud
Before looking to future technology developments associated with VDI; the progression
from the centralized computing model of the IBM System/360 mainframe computer, to
the cloud offerings available in 2015, will be analysed.
IT service delivery began in the days of mainframe computers. A mainframe computer
is essentially a large, powerful, reliable computer (Hardiman, 2014) capable of running
thousands of processes and requests simultaneously and boasts the lowest downtime of
any computing environment. This is achieved by designing reliability, availability; and,
serviceability characteristics into the architecture (Beattie, 2013).
Mainframes use a centralised model of computing where the data and programs are
stored and processed from a data centre. Historically users would interact with
mainframes using dumb terminals. A dumb terminal essentially communicates with a
central sever but performs no processing or storage of information locally. More
recently terminals can be emulated, removing the need for a dedicated hardware device,
leaving users to connect to the IBM System Z OS using TCP/IP (Pomerantz, 2008).

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Figure 13: Mainframe Architecture (Ramirez, 2000).
Not only is the service delivery comparable to how VDI delivers virtual desktops to
users with all the programs, data, and settings being stored centrally, users can also
access their desktops using terminals. These have developed from dumb terminals and
can take many forms like such as the thin, zero and thick clients previously mentioned.
An inherent characteristic of the IBM Mainframe is inbuilt virtualization that has been
iteratively developed through generations of mainframes. The mainframe virtualization
brings consolidation of multiple servers onto a single mainframe; sharing of processer,
memory, network and input output devices across all virtual machines installed on a
mainframe (IBM, 2015a). This is comparable to the desktop virtualization utilising
hypervisors to share workloads across underlying hardware.
Whilst this model of computing has mostly been replaced by the server side computer
or in recent generations the move towards cloud computing. The mainframe computers
are still used by many of the Fortune 1000 companies, this is especially relevant within
‘e-business’ hosting commercial scale databases, transactional services, and
applications. All of this is done with a greater degree of security and availability than
competitors (Ebbers et all, 2011).
The mainframe influences over modern computing and VDI is materialised with IBM’s
VDI offering. Smart Terminal Architecture in a Secure Hosting Stash (STASH) is
described as “VDI on steroids” bringing mainframe reliability, performance and security
to the VDI market. (Pereira, 2012) Designed to bring more security to mainframe
computing, as the adoption of mobile devices and proliferation of BYOD initiatives are
greatly increasing (Raddling, 2012).
After the centralized mainframe day’s service delivery methods began to change
towards a distributed model of client server with the evolution of PC’s. In client server
computing the client is the terminal from which a user makes requests to the server
resource provider. Programs can reside on users computers running on top of the
operating system, or a network share interacting with the server. Once the request has
been completed the connection is terminated (Rouse, 2008). This differs from the
mainframe where all intelligence is secured onto the central host mainframe server.
PC’s are intelligent terminals with their own processors; memory and input/out devices
that have not been virtualized and shared across a network. VDI is a variation of the
model of computing where the client is now stored centrally on the host server and
interacted with using a remote display protocol.

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Things have completed a cycle in returning to centralized computing with the evolution
of cloud computing. Cloud computing is essentially the storage and access of programs
and data over the Internet instead of via hard drive storage. It shifts from locally stored
programs to consolidating many distributed platforms into one location. Cloud service
providers lease their available resources from a shared pool on demand to users on a
pay-as-you-go-basis (Fox, 2011). These pools share their resources to achieve
economies of scale (Jackson, 2011).
2.8 Cloud Computing:
Cloud Computing or “the cloud” is a term used to define on demand service over the
Internet. These services can be characterised as including benefits like: elasticity; pay
per use; and self-service (IBM, 2015b).
There are several different types of cloud deployment models. These are: public,
private, and hybrid.
Figure 14: Infographic representing different cloud deployment models (IBM, 2015).
Public Cloud (external) is the most recognisable model of cloud computing whereby
companies provide services to paying customers from their underlying shared
infrastructure over the Internet. This can be accessed by multiple customers unlike
private cloud (internal) where the infrastructure is dedicated to a single organization.
Hybrid Cloud comprises both internal and external services with an organization
providing and managing some services; whilst also having resources provided
externally (ThinkGrid, 2015).
Rather than looking to implement private virtual desktop deployments, companies can
now lease desktops hosted in the cloud. This type of service is called DaaS (Wood,
2012).
2.9 The future of VDI? Desktop as a Service (DaaS)
What is DaaS? DaaS is an evolution of VDI that places it within a cloud infrastructure
(Knuth et al, 2014). All the required infrastructure is hosted by the service provider in
their data centre. So it is essentially a third party hosted VDI solution where the
provider is responsible for hardware; data storage; backups, security; and updates.
Whilst the control of the desktop, applications and security is the users responsibility
(Rouse, 2013). It could effectively be called ‘VDI as a service’ moving the risk and cost
associated VDI networks into the hands of experts.

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Figure 15: Example DaaS Infrastructure by VMware (VMware, 2014c).
2.10 Benefits of DaaS:
DaaS also reaps some of the same benefits that come from implementing a VDI solution.
However, it comes with its own advantages and disadvantages to an enterprise.
Move from Capital Expenditure (Capex) to Operational Expenditure (Opex): The initial
capex required to implement a VDI solution limits the uptake of the technology. With
DaaS the cost is moved to an operational expense, opening up the possibility for
enterprise and individuals to consider DaaS instead of a traditional desktop (Botelho,
2013).
Scalability of Solutions: With DaaS the options to incrementally scale the solution to be
either larger or smaller are simple. If you are provisioning or de-provisioning users the
worries about storage capacity damaging users experience are completely removed
(Knuth, 2014). The only consideration will be the increase in rental costs. There is no
need to plan for future growth as this can be dealt with dynamically at the required time
in an agile manner.
Expert Knowledge: To implement a VDI network requires months of dedicated planning,
testing, and troubleshooting to eventually develop a useable solution. With DaaS, all the
expert knowledge has already been used to set up the service offering so an
organization or customer does not need to even consider it (Knuth et al, 2014).
Transparent Costs: VDI cost calculators and online design tools can be used to help
confirm the costing for a project. However these costs almost always spiral with
unforeseen issues or upgrades. With DaaS the costing is simple. The number of users
multiplied by the cost per user. This cost is completely transparent and adds an element
of predictability to a costing strategy (Stevenson, 1995).
Device Lifecycle: As with VDI the desktops are running from within the data centre so
any device, old or new can be used to access the VM. If thin clients are adopted the
amount of moving parts is also greatly reduced so the threat of damage is reduced.
Disaster Recovery: As no data is being stored on client devices but is all stored and
backed up on multiple servers DaaS can be seen as a suitable solution to potential
disaster recovery. The cloud as a whole now offers organizations a choice to move away
from traditional backups at local data centres on disks, to hosting their backups in the

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cloud. This poses new questions about: the security of hosted data; the authentication
of users accessing the data; the bandwidth required to utilize the cloud offering; and,
ultimately how long it would take to restore the data in the event of a disaster using an
internet connection (Gsoedl, 2011).
2.11 Drawbacks of DaaS:
Trust in the Cloud: By moving to a DaaS offering the organization needs to be
comfortable that their data and applications will be secure and available upon request
instantly. There is a lot of pressure placed on service providers to offer a faultless
service as DaaS exists to, alleviate costs, stress and problems associated with VDI
networks (Knuth et al, 2014). There are always concerns that outages will leave users
without access to a suitable environment to work in. When you control the outage the
priority and effort can be dedicated. However with a DaaS provider you are only as high
in the priority order your payments allow and cannot exert control over the resolution
of potential problems (McLaughlin, 2014).
Bandwidth Requirements: When embarking on a VDI or DaaS project a key requirement
is to have enough bandwidth to comfortably deal with the increase in network traffic
(Mullins, 2012). Without sufficient bandwidth the solution would be relatively
unusable, the screen would show latency; applications would freeze and the users
experience would be negatively impacted.
Network Latency: Over a network there is only so much that can be invested into
bandwidth to improve performance. Network latency will grow as packets are dropped
as they travel between the client and the hosted server. A drop in packets results in a
noticeable decrease in performance for users. Typical symptoms include keyboard
lagging and screen freezing. The more latency spikes, the more disruption for the end
users (Laverick, 2012).
2.12 DaaS Licensing Constraints:
As Microsoft currently dominates the desktop OS market, DaaS solutions must comply
with Microsoft’s licensing rules. There are several different types of licence available,
but only one viable option for DaaS.
Original Equipment Manufacturer (OEM) licensing is used by system builders - Lenovo,
HP, Dell - to preinstall Windows OS’s onto computers before sale. This type of licence is
limited to installation on the original machine, meaning it cannot be removed and used
on another device.
Full Package Product (FPP) licences are purchased from retail, online or in store. They
are either standalone full licences or upgrades from previous versions. When
purchasing this licence you again enter into an agreement with Microsoft Software
Licence Terms. The terms of these agreements vary depending on the country of
purchase and the individual product. Microsoft governs the rights as to how many
devices the software can be installed on, whether the licence can be transferred or used
for commercial purposes.
Volume Licensing (VL) is designed for customers buying more than one licence,
commonly used by business for commercial purposes. VL is governed by a set of
Microsoft rules called the Product Usage Rights (PUR). The type of licence we are
concerned with for VDI and DaaS is VL, with specific PUR that allows for the Windows
OS licences to be running on the DaaS provider’s hardware.

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In an ideal world, DaaS providers would be able to pre-purchase a vast numbers of
licenses to deploy as per customer requirements. Yet in reality this conflicts with the
PUR as the users of the licence will not be internal employees to the purchasing
company.
Another option would be for a DaaS provider to pay Microsoft a monthly fee for the
number of licenses used. While Microsoft has a Service Provider License Agreement
(SPLA) for this purpose, client licenses for Windows are excluded from this agreement.
This has left DaaS providers with a few options to deploy their desktops. The first
option is to manipulate a Windows Server OS to make it appear as a normal Windows
desktop, giving the user the allusion they are working on Windows 7 or 8. This is
achieved by using the ‘Desktop Experience’ feature which adds components found in the
client OS to the server OS. This includes software such as Windows Media Player,
Windows Defender; and Disk Clean-up among others (Knuth et al, 2014).
This option, unlike with client licenses for Windows 7 or 8 as the server OS is permitted
under the SPLA program. Allowing DaaS providers to factor in usage into their monthly
costs to the customer, and monthly payments to Microsoft.
The second option is to Bring Your Own Licence (BYOL), which has its own
complications as it requires a special licence to run the OS on someone else’s hardware.
This is called Virtual Desktop Access (VDA), a Microsoft strategy designed to simplify the
licensing requirements for virtual environments.
To obtain VDA users can access this feature as part of their Software Assurance (SA)
maintenance program for VL purchases. This program essentially spreads payments
whilst offering training, support and, free upgrades of software. VDA is designed for
Windows devices rather than users. So a user wishing to run Windows on an iPad or
iPhone would require an additional $100.00 licence to remain compliant. Overall this
creates a premium price for virtualized desktops to be delivered on non-Windows
devices. This threatens BYOD campaigns and questions the cost effectiveness of VDI and
DaaS over traditional OEM desktops (Fraser, 2014).
User and DaaS providers could look to other OS’s such as Linux where there are no
limitations on deployment via DaaS. However as Microsoft almost has a monopoly over
the workplace, the use cases for this are minimal and cost prohibitive.
There is speculation in the industry over Microsoft releasing a special VDI licence that
will solve the problems and complexities highlighted. Critics blame Microsoft for
slowing the uptake and growth of the DaaS market, highlighting the knock on effect on
their cost models.

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3. Technology Review:
This section will give an overview of the service providers to be analysed throughout the
remainder of the report. It will provide an introduction to the companies and the
different service packages offered. There will also be an introduction to the supporting
partners for this project, their enterprises and a case study of a DaaS implementation.
The chapter will also discuss the involvement of Microsoft Remote.App and why it will
be excluded from the remainder of the report.
3.1 Amazon Workspaces:
3.1.1 Introduction:
Amazon’s DaaS solution began in 2013 with the announcement of ‘Workspaces’.
Amazon Workspaces (AWS) promised to provide Windows 7 desktops on demand to
almost any device, such as tablets, desktop PC’s, mobile phones, or the next emerging
trend of device (Amazon, 2015a). The AWS service offers centrally managed cloud
virtual desktops that are provisioned as required using their online management
console.
3.1.2 Packages:
Amazon offers a range of different bundles from Value to Performance Plus. These differ
in terms of applications offered, memory, CPU and storage. All of the AWS packages
offer persistent desktops for users and a console to facilitate the management of the
cloud desktops (De Lacvivier, 2013). The packages are detailed below:
WorkSpace Bundle: Hardware Resources:
Value 1 vCPU, 2GiB Memory, 10GB User Storage
Standard 2 vCPU, 4GiB Memory, 50GB User Storage
Performance 2 vCPU, 7.5GiB Memory, 100GB User Storage
(Amazon, 2015b)
WorkSpace Bundle Applications:
Value, Standard,
Performance
Utilities (Adobe Reader, Internet Explorer 9, Firefox, 7-
Zip, Adobe Flash)
Value Plus, Standard Plus,
Performance Plus
Microsoft Office Professional, Trend Micro Worry-Free
Business Security Services, Utilities (Adobe Reader,
Internet Explorer 9, Firefox, WinZip, Adobe Flash)
(Amazon, 2015b)
3.1.3 Supporting Partner:
Peyton Resource Group (PRG) is a US based technical resource
staffing and services company offering technical solutions to
businesses. The Technical Solutions side specialise in
leveraging the benefits of mobility and cloud to organisations.
PRG are currently partnered with Microsoft and Amazon for their cloud offerings such
as Office 365 and Workspaces. The company exclusively uses the software and
hardware configurations they offer themselves, gaining hands on experience with the
cloud environments.

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3.1.4 Case Study Implementation: Unnamed Company
PRG worked with a regional staffing/recruiting company that had over 150 employees,
dispersed at three office locations. The challenges/ motivations for this project
included:
 Computer equipment coming to the end of lease meaning new resource needed
to be acquired for the offices and employees
 Corporate email was currently hosted via an on premise mail server, which
experienced occasional downtime meaning outages from email communications
 Lack of corporate backups protecting data
 The need to introduce more flexibility for employees when accessing computing
resources
The solution implemented was part of a wider cloud migration, rather than solely
converting users to Amazon Workspaces. PRG subscribed the company to Office365
meaning the email was migrated to use Exchange Online, and user data was stored in
OneDrive.
Next users desktops were relocated to work inside Amazon Workspaces, meaning that
the requirement for corporate backups was met, as all user directories within the
Workspace are backed up every 12 hours. Further to the desktop migration the
technology infrastructure was also migrated to Amazons Web Services so that all
resources (web server, active directory; file servers) are now located in the cloud.
This migration resulted in a solution that offered: high availability, redundancy,
business continuity, and disaster recovery options. Employees are now able to access
their files and desktops from nearly any device, and the corporate email is no longer
experiencing any problems. Overall the solution was future proofed meaning that
physical hardware is minimized and maintenance and deployments of resources are
dramatically simplified.
3.2 VMware:
3.2.1 Introduction:
In 2013 VMware completed the acquisition of Desktone, Inc an industry leader in DaaS.
This acquisition has allowed VMware to combine their skills and market position with
virtualization software like Horizon View, with Desktone’s cloud service platform for
delivering applications and desktops as a cloud service (Poonen, 2015).
The combined DaaS solution is called VMware Horizon Air. It is built using VMware
vCloud Air their public cloud platform, which is used to run some of their service
offerings like: Infrastructure as a Service; disaster recovery and Application as a Service
(VMware, 2014d).
VMware customers can choose to opt into this hybrid cloud architecture supported by
vCloud where resources are managed both internally on premises, and externally in the
cloud. This hybrid architecture applies to VMware’s VDI solutions so users can choose
between or combine on premise VDI delivery, using VMware View with their cloud
desktops using Horizon Air (Cheng, 2014).

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VMware Horizon Air delivers both cloud hosted applications and persistent and non-
persistent desktops to users on any device, in any location. The operating systems
available include Windows XP, 7, 8 as well as Windows Server 2008/12.
Similar to the Amazon Workspace solution all the licensing costs for the Server OS are
included in the monthly fee. However users requiring client OS’s such as Windows 7
and 8 are required to bring their own licenses. (Madden, 2014a)
3.2.2 Packages:
VMware as with most DaaS providers operate their DaaS offering as a subscription
service. The range of desktops covers three models: standard, advanced, and,
enterprise. These packages are currently only available with the minimum order
requirement of 50 desktops, one of the knock-on effects of the lack of Windows 7 SPLA.
Users looking for smaller order quantities can look to VMware’s partners who offer
Horizon DaaS with different offerings and additional services. The different hardware
bundles are listed below:
Horizon Air Bundle Hardware Resources:
Standard 1 vCPU, 2GB vRam Memory, 30GB Storage
Advanced 2 vCPU, 4GiB Memory, 60 GB User Storage
Enterprise 4 vCPU, 7.5GiB Memory, 120GB User Storage
(VMware, 2014d)
Molten Technologies are a UK based independent specialist in
virtual desktops. They provide consulting services making the
complexities of VDI & DaaS as simple and price effective as possible.
Ultimately allowing companies to leverage these transformational
technologies in the most suitable and appropriate ways.
Molten also offer cloud hosted virtual desktops through a partnership with VMware
(formerly Desktone). This partnership creates a flexible, scalable cloud service while
still maintaining the control of an in house deployment.
Further partnerships with Wyse the global leader in thin computing enable Molten to
offer world-class thin-client hardware and software for their implementations. Finally
Molten partnered with HP Alliance One enabling them to leverage solutions, tools and
resources that speed up deployments and optimise infrastructure for customers.
3.2.4 Case Study Implementation: Thames Water Desktop Conversion
Molten implemented a VDI solution for Thames Water using their DaaS platform.
Thames Water wanted to achieve cost savings but also boost productivity through
improving flexibility and security for employees.
Another requirement partly fuelled this project as Thames Water needed
to migrate from Windows XP due to the OS no longer being security
patched and supported. The primary use cases being targeted within
Thames Water included:
 External contractors needing PC access.
 Internal call centre staff with a basic core load of non-intensive applications.
 Introducing a BYOD campaign for employees.

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These use cases and the business need to migrate from Windows XP to Windows 7 made
it a cost effective time to trial a DaaS implementation. Now up to 2000 desktops are
running hosted in the cloud environment.
3.3 Citrix:
3.3.1 Introduction:
The Citrix DaaS solution differs from the likes of Amazon & VMware as they use partners
to deploy their solutions rather than hosting the DaaS solution as part of their own
multi-tenant cloud platform. To use a Citrix solution you first have to find a relevant
partner and look at their individual implementation (Citrix, 2015a).
The benefits of this is that Citrix has thousands of partners worldwide that offer hosted
desktops to fit specific vertical industries, or unique use cases for DaaS adoption. This
brings an element of customization that may be more suitable to SME’s (Citrix, 2015b).
Citrix is currently the market leader in DaaS serving over 350,000 subscriptions through
its worldwide partners scheme. It is currently looking to develop a platform solution
that will run on Microsoft’s Azure called Citrix Workspace Services. This platform will
allow both partners and customers to rapidly build and deploy DaaS and virtual
application delivery amongst other cloud services. This platform will utilise pre-existing
Citrix software like: XenApp and XenDesktop which are used for application and
desktop delivery respectively (Citrix, 2014a).
BrightCloud are a UK based independent consultants with over
10 years experience specialising in managing and hosting cloud
services.
BrightCloud hosts and fully supports desktops and mission
critical applications for customers. Offering fully customizable and scalable DaaS
solutions as part of a cloud strategy. BrightCloud partnered with Citrix to deliver their
virtual desktops and applications. They also utilize VMware products for server
virtualisation, while offering Microsoft SPLA licenses or Office365.
3.3.3 Case Study Implementation: SeeAbility
BrightCloud have been managing SeeAbility’s IT infrastructure for
over 10 years now. SeeAbility is a registered charity supporting people
with multiple disabilities. The staff – nurses, therapists, and
rehabilitation practitioners – need access to case files and medical
records on demand, completing any admin on the spot.
Virtual Desktops where seen as the ideal solution as the required information could be
accessed from any device without returning to a base office. This was combined with the
need for a hardware refresh, meaning cost savings could be realised by moving to the
cloud.
By outsourcing the IT to a fully managed Infrastructure as a Service model, SeeAbility is
able to benefit by having infrastructure; security; and resilience it otherwise couldn’t
afford. The charity is always expanding so the scalability benefits of cloud solutions are
also of huge benefit.

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3.4 Microsoft Azure: RemoteApp
3.4.1 Introduction:
RemoteApp code named ‘Mohoro’ was supposedly Microsoft’s first venture into the
DaaS market (Knuth, 2013). Mohoro upon release was actually a hosted version of RDS
using the Azure cloud platform.
This enables enterprise to deliver windows server based applications to end users
regardless of the operating system they are using. There are currently RemoteApp
applications for Mac, Windows, iOS, Android, and Windows Phone meaning users can
access their cloud-hosted applications on any of these devices.
Users signing up for the RemoteApp service can opt into two different deployment
options. Either ‘cloud collection’ for all their data to be stored in the Azure cloud. Or a
‘hybrid collection’ with resources being stored in the Azure cloud complimented local
network resources.
One key difference with RemoteApp service when compared to the other service
offerings, is that users cannot access a complete desktop. Windows Server 2008 OS or a
Microsoft Office image can be provisioned but users only gain access to the applications
and data rather than a full desktop experience. This arguably makes the offering
Application as a Service (AaaS) rather than a DaaS.
Delivering the applications in this way without the complete desktop Windows avoid
their own complicated desktop licensing and ultimately differentiate them from the
other competitors in the DaaS market. For the scope of this project the author will not
be reviewing or comparing Remote.App against the other DaaS providers.

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4. Requirements and Analysis:
This chapter discusses the aims of my project, breaking down the requirement
statements into manageable steps.
The requirements are as follows:
 Gain support and access to DaaS services offered from: Amazon, VMware and
Citrix. (4.3.1)
 Analyse the specific services offered from each DaaS provider. (4.3.2)
 Review the advantages and disadvantages of each service providers DaaS
offering. (4.3.3)
 Compare the features and benefits of each solution against each other. (4.3.4)
 Produce evaluation document including the analysis of features to publish online
adding to the VDI & DaaS community. (4.3.5)
 Develop evaluation criteria to test each DaaS environment. (4.3.6)
 Create concrete testing scenario/ control conditions (4.3.7)
 Reach out to targeted enterprises to gather their requirements to analyse the
suitability and viability of moving to DaaS. (4.3.8)
 Analyse viability of enterprises moving to a DaaS solution (4.3.9)
 Conduct a survey comparing users experiences when using a traditional desktop
computer vs. working in a virtual environment in the cloud or using an inbuilt
VDI solution. (4.3.10)
4.1 Ethics:
As the analysis of targeted enterprises moving to DaaS involved human participants, it
must comply against the University of Sheffield’s ethics review procedure and policy.
The participants of my survey are happy for the results to be attributed to their
business, but the individual participants completing the survey have been anonymised
(The University of Sheffield, 2015).
4.2 Initial Analysis:
The project is naturally split into two sections. The first analyses and reviews each of
the DaaS provider’s solutions before evaluating them based on testing criteria. The
second focuses on the application of DaaS in enterprise using real life examples to
analyse the feasibility and viability of replacing a standalone desktop.
4.3 Detailed Requirements:
4.3.1 Gaining DaaS Providers Support:
As the capital and expertise needed to implement a VDI or DaaS solution are so vast
much of the success of this project will rely upon gaining the support of DaaS providers.
Without their support and access to their hosted solutions there will be nothing to
evaluate and compare. This will result in the comparison being based purely upon
literature rather than combined with hands on experience.
To gain support, the initial approach will involve sending emails: introducing myself;
providing project background and my project aims; concluding with how providers
could get involved. To the respondents a call or videoconference will be requested to
discuss their involvement and support.
Where appropriate providers will be contacted directly to gain their support covering
the same content as the email. Phone calls will be used primarily once a company has

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shown interest to further persuade and introduce the project objectives whilst
answering any questions. Face to face meetings can be scheduled however this is
dependent, on geographical locations, as some service providers are non-UK based.
Rather than reaching out to the service providers directly, each of the companies being
evaluated offer partner schemes with other companies selling access to their service
offerings. These respective companies will also be reached out to in order to gain
support in a similar way. This will be deemed successful if access to one environment
from VMware, Citrix and Amazon can be provisioned.
4.3.2 Analysing Service Offering
Although each DaaS provider provisions customers access to Windows desktops in the
cloud, they each have a different strategy and approach to their service.
When analysing the service offerings I will focus on:
 The pricing strategy adopted
 The support plans that come with each offering and additional support that can
be purchased
 The specification offered for each virtual desktop
 The features and technology included
This will be deemed a success if the analysis covers all the individual requirements and
is complete for the VMware, Citrix, and Amazon environments. This analysis will be
included in the evaluation document produced for 4.3.5.
4.3.3 Evaluation of Advantages & Disadvantages
The evaluation of advantages and disadvantages will be based upon the analysis of the
features of each environment. A practical angle will also consider personal experiences
of using the environments and the results of testing. This will be highlighted through
the use of ‘F’ for features, and ‘P’ for practical to show where the analysis has been
developed.
I will gauge this a success if the advantages and disadvantages cover both theoretical
features and practical hands on experience.
4.3.4 Comparing the Features & Benefits:
A table will be formed for each DaaS provider to directly compare the different service
offerings. This will be based on the information gathered in previously and additional
research.
The areas for comparison will include:
 The different packaged service offerings in terms of hardware and software
available.
 The price per month for each different package
 The minimum order level
 The different support plans available to customers.
 The Service Level Agreements (SLAs) associated with each desktop and any
options for improved or differing SLAs
 If the desktops offered are persistent or non-persistent or both.
 The graphical capabilities for each environment.
 Which operating systems are supported

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 How the management of desktops is achieved.
 The different client devices supported
 Whether the environment supports USB and other peripherals.
 The remote transfer protocols used & available to the user.
 If active directory integration is available
 If a hybrid cloud implementation is possible.
The table will be supported with a textual analysis if the comparison is not clear.
This requirement will be deemed successful if the tabular comparison is complete for
each provider’s without blanks or missing information.
4.3.5 Produce Evaluation Document:
The evaluation document is intended for IT professionals aiming to learn more about
the specific features and benefits of each solution. The document will be shared online
and emailed to a number of VDI and DaaS forums to establish if they are interested in
hosting my report.
The evaluation document will include:
 Tabular comparison of features and benefits.
 Introductions to each service provider.
 Pricing options for each service
 Support plans for each service
 Features and services associated with each environment and technology
breakdown where appropriate.
 Recommended use cases for each environment.
 Analysis of advantages and disadvantages.
This will be a success if the document is hosted publicly online, freely accessible and
available without restriction. The format will be an interactive .PDF so it can be read in
browser or printed.
4.3.6 Develop Testing Criteria:
The testing will be universal across all environments using the same tools to remain
consistent. Testing will be conducted using the software clients for PC’s rather than thin
or zero clients. Using dedicated hardware would provide another angle of comparison
but procuring such devices is beyond the scope of this project.
Here is a brief overview of each test case highlighting the aims of the test.
 Boot times: compare the different times for the VM to boot
 Peripheral Support: comparing how each software client supports different
peripheral devices such as USB and Microphones
 Software Clients Available: comparing the different platforms that the software
clients from each provider are available for
 Supported Hardware Clients Available: comparing the different hardware
devices that are supported by each provider. This will include thin and zero
client hardware
 Performance Benchmarking: conducting performance benchmarking on each
environment to compare against each other and physical machines
 Storage I/O Performance: analysing the performance of the underlying storage
that underpins each DaaS environment

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 Network Performance: analysing and comparing the network performance and
stability in each environment
 Graphical Performance Testing: analysing and comparing the graphical
performance in each environment
 Application Loading Times: comparing the loading times for a set of enterprise
applications across each environment
 Mobile Interface Heuristics Evaluation: analysing and comparing the mobile
applications from each provider against some modified heuristics evaluators
Each test case will be covered in more detail in the design section of this paper.
This requirement will be deemed successful if the test cases are completed for each
environment to allow direct comparison.
4.3.7 Testing Scenario / Control Conditions
To make the testing as fair as possible it will be conducted under strict control
conditions. The devices used to test each environment will remain consistent so to get a
fair representation of the performance of each software solution. The devices being
used are an: Apple Mac Book Pro; Apple iPhone 5S; and Samsung Galaxy Android Tablet.
The testing will all be conducted using the Mac software client for each environment,
from the same location using an Ethernet connection. When testing the mobile
applications from each provider the Samsung Tablet will be used as each provider offers
a mobile application for the Android platform. The wireless Internet connection to the
tablet will be tested from the same location to minimise fluctuating Internet speeds.
The same tests will be repeated in each environment testing at roughly the same time
each day. Ultimately taking an average value over 5 days for each test result.
Further control conditions will be highlighted in the design section of this report.
This requirement will be deemed as successful providing it has been conducted under
the testing conditions highlighted above.
4.3.8 Enterprise IT Requirements for moving to DaaS
Part of the analysis will look at three businesses of varying sizes to observe how viable a
move to a DaaS offering would be. This will involve analysing their current methods for
delivering IT and looking to see if any of the benefits of DaaS could be realised by each
organisation.
The enterprises targeted will fit into the following general segmentation of enterprises
based on the number of employees (European Commission, 2014).
 Small Enterprise - <50
 Medium Enterprise - <250
 Corporate Enterprise - >250
The targeted enterprises will each be approached in a similar method as the DaaS
service providers. Specifically by sending an email inviting them to a phone
conversation introducing myself, my project, and how they can get involved.
This will be regarded as a success if a business from each segment allows for me to
gather their requirements and use their business as a case study for moving to DaaS.

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4.3.9 Enterprise Viability of moving to DaaS
The requirements of each enterprise will be analysed to comment on the viability and
feasibility of moving towards DaaS, if any of the benefits of DaaS could be reaped.
4.3.10 Survey Analysing User Experience in DaaS Environment
This will gather information from users who have actually moved from a physical PC to
a cloud-hosted desktop. Questions will be asked around their experience before and
after, highlighting any differences or problems, also if they utilise the benefits of a cloud
hosted desktop. The survey will be covered in more detail in the design section of this
report.
This requirement depends upon the support of my partnered DaaS providers and the
clients they have previously worked with.

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5. Design:
This section will cover the design of test cases to evaluate each DaaS environment with
the justification behind each test case. Focus will be placed on the control conditions
used for each case to ensure accurate results.
The design of my survey for case study enterprise will also be included to show the
reasoning behind my choice of questions.
5.1 DaaS Environments Test Case Design:
1) Boot Times: Recording the time taken from, the session being initiated by the
connection broker until the desktop has completely booted.
The different options considered are listed below:
Event Viewer: Windows 7 includes a feature called Event Viewer which provides an
overview of system events including boot times. Boot times are assigned the event ID
100 with the time displayed in milliseconds (MS). Upon trailing this test in the Amazon
environment, as the underlying OS is Windows Server, the same event didn’t appear to
exist. This made it impractical to use, as the test would be inconsistent across all
environments.
Figure 16: Screenshot from Event Viewer (EventViewer, 2015).
Mass360 Boot Analyzer: This freeware is designed to log the boot times when the
computer restarts, displaying the information graphically day to day. This software is
desirable, as it would run automatically in the background on Windows start-up.
Unfortunately after testing the software in each environment the BootAnalyzer would
not function within the VMware environment.

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Figure 17: Screenshot showing the Boot Analyser Interface (BootAnalyzer, 2015).
Visual Basic Script: This script once initiated restarts the computer. Upon booting to the
desktop an option box displays how long it took to completely boot the computer. The
test worked perfectly in each environment so is the option selected.
The test will be run once every five days after fully booting the system. The script will
be executed, noting each restart time. The average of these values will then be used to
define boot time for each environment.
2) Peripheral Support:
The peripheral support will be tested in all environments to see if they can cope with
redirection from the client to the virtual environment. Commonly used peripherals will
be tested such as:
 USB Port: This will be tested using an External USB hard drive specifically
formatted for Windows. Other tests could include the use of a wired keyboard
or mouse. If the USB device is readable and can be used to transfer files too and
from the virtual environment to the external device the test will be passed.
 Headphones: This will test the sound redirection using a 3.5mm jack port on
available devices to see if sound can be directed to the headphones or plays
through the native speaker.
 Webcam: As the MacBook I am using for testing includes a webcam this will be
tested to see if the webcam can be redirected and used within the Skype
application.
 Microphone: Testing to see if the natural microphone attached to devices such as
laptops, phones and tablets can be automatically re-directed to the virtual
session.
 Printers: Attempt to add a networked printer via IP and send test documents.
 Dual Monitors: Test to see if the virtual session is capable of supporting multiple
monitors.
The exact same devices and test cases will be repeated across each environment to
ensure consistency, and accuracy in the comparison.
3) Software Clients Available:
The supported software clients provided by each service provider to access their virtual

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environments. This will include OS clients for Windows, Mac and Linux. Combined with
mobile platforms like Android and iOS.
4) Supported Hardware:
Listing all the supported hardware partners including: thin clients; and zero clients.
When listing the hardware it may be appropriate to comment on the, costs, features and
vendors that provide these devices.
5) Performance Benchmarking
Each virtual environment will be tested using a piece of software called PassMark
Performance. This software is designed to performance benchmark Windows
computers against each other.
A similar test for performance benchmarking a VDI environment against a MacBook Air
was completed through a collaborative project between IBM and a company called
Atlantis (Atlantis, 2013). This is a suitable test, as it will allow for direct comparison of
performance possible within each environment.
The software will specifically test:
 CPU: Testing mathematics operations for integer and floating points;
compression; encryption; and sorting
 2D Graphics: Testing drawing lines; bitmaps; fonts; text and GUI elements
 3D Graphics: Testing simple to complex Direct X 3D graphics and animations
 Disk Tests: Testing read/write, and seeking within disk files
 Memory Tests: Testing the allocation and memory speed efficiency for cached
and un-cached data, RAM availability, and latency
PassMark also provides an online database of previous tests run on a variety of physical
and virtual devices. Comparing the virtual tests to a comparable physical PC of the same
specification will show how well the virtual environment is able to perform.
The control conditions are to run the test at roughly the same time over five days, noting
each score and producing an average over the test period. The software will be the only
application running in each environment when the tests are running to ensure a fair
representation on performance.
6) Storage I/O Performance:
The storage performance will be tested using software to simulate a load upon the
underlying storage system.
One approach is to use a tool called I/O Meter. This has been used as an industry
standard tool to test the workload on underlying storage subsystems. The software
allows for the read/write and sequential/ random distributions to be set so the
configuration can closely match the workload to a VDI environment. A test file is then
created to simulate the creation of a workload.
The I/O profile will be approximately 80/20 write/read , 80/20 random/sequential,
with block sizes of 4k. The block size from using real Windows applications varies
between 512B-1MB, but the vast majority will be 4k. As I/O Meter does not allow for
variable block sizes this has been set as a constant (Atlantis, 2014).

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Figure 18: Access Specification Template (IOMeter, 2015).
Figure 19: Example IOMeter Test Results (IOMeter, 2015b).
Another approach would be to use a piece of software called LoginVSI. This is another
VDI performance testing software tool, however is not available as freeware. This
software simulates real user workload rather than test files. After experimenting with
the trial version it required a minimum of 20 virtual machines and access to the domain
controller. This is beyond the access rights and scope of my project as a ‘customer’ of
the DaaS solutions.
7) Network Performance:
Analysing the network performance will focus on the: ping; upload and download
speeds achievable in each environment to see which has the best performing network.
 Ping: A ping test is a way of testing if a device is available on a network. This is
useful for calculating the latency and delay between two computers. The ping
test also provides details on packet loss; and jitter, giving an accurate
representation of the network quality.

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Figure 20: Ping Test Results (Ookla, 2015).
 Upload & Download Speeds: An online testing tool provided by a company called
Ookla can be used to measure the download and upload speed in Mbps.
Figure 21: Upload and Download Test Results (Ookla, 2015b).
8) Graphical Performance Testing:
Commercial graphics card benchmarking software was considered for this test like
3DMark the industry standard. But upon trial this was not suitable for the DaaS
environments tested, as they require dedicated graphics cards. The test failed to run so
a different approach was required.
When researching VDI graphics a company called Nvidia offer virtualised graphics
delivery for cloud and virtual environments. They provide a trial virtual desktop that
highlights the 3D graphical capabilities possible using their solutions. This included
various stress tests to highlight how well their solution can perform (Nvidia, 2015).
These tests are further supported by an independent whitepaper into 3D graphics for
virtual desktops. This paper concluded by listing a number of test cases to stress test 3D
graphics (Bass, 2014). The test cases below have been developed from these sources.
 HD PowerPoint presentation using high resolutions images and transition
effects between each slide.

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Figure 22: NVidia HD PowerPoint Presentation example (Nvidia, 2015b).
 HTML5 Applications: HTML5 applications can use a JavaScript API for rendering
2D and 3D computer graphics via compatible web browsers. These tests will log
how well the DaaS environments cope with 3D graphics being delivered through
a web browser.
Figure 23: Demonstration of a WebGl graphics application (HelloRacer, 2015).
 Interactive 3D PDF’s can be generated from CAD software to embed models that
are fully interactive and platform independent. These PDF’s can then be used to
test the rendering of 3D graphics and performance.
Figure 24: 3D PDF demonstrating an interactive lung (3DPDF, 2015).

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 1080p HD YouTube videos can demonstrate how well the virtual environments
cope with streaming HD video content to the client device.
 HD Videos can demonstrate how a video can be played that is stored on the
virtual desktops hardware or allocated storage.
For each test case the following criteria will be commented upon in order to detect how
well each environment is performing under the stress tests.
 Stuttering / Skipping: This occurs when the content has a quality defect that
results in irregular displays between frames and content not appearing
smoothly.
 Sound Quality: If the sound skips or plays smoothly without recognition of any
issues.
 Image Quality: If the image being displayed accurately reflects what would be
possible on a physical PC.
The control conditions for this test will include running the same test case on each
environment using the same client device. Test will be conducted over 5 days at the
same time to ensure the reliability, minimising potential anomalies. No other
applications will be open when the tests are running.
9) Application Loading/ Opening Times
A core set of applications will be tested that are most commonly used throughout
enterprise. These include: Microsoft Office Package, Firefox, Chrome, Internet Explorer,
Adobe Acrobat, and Team Viewer. This list of applications has been developed utilising
research into global download figures of the most popular freeware (Software Informer,
2015).
A piece of software called AppTimer will be used to initiate and time each program
opening. This software can be installed in each environment to create comparable
statistics for application loading times. The same version of each application will be
installed into each environment; with tests running 10 times with a gap of 5 seconds
between each iteration. The tests will be run after the desktop has first logged on, so
applications will not be stored in cache memory. The value for initial load times and
cached load times will then be averaged across the 5 test days.
10) Mobile Interface Evaluation
Each provider offers a tailor made mobile application that can be used as a portal to
access their cloud hosted desktops. The purpose of this test will be to evaluate the
functionality and heuristics of the mobile app. The testing criteria has been developed
from Nielsen’s usability heuristics (Nielsen, 1995). However, it has been combined and
modified with research into touch screen mobile heuristics to produce the following test
criteria (Inostroza, 2012).
Test Criteria
Screen resolution: Rotatable: Ability to use the Desktop in portrait or landscape
depending on the orientation of the device.
Auto-adjust: Screen resolution should automatically adjust to
match the client device being used.
Touchscreen: Pinch to Zoom: Intuitive controls like pinching two fingers
together should zoom into the desktop.
Multi-touch: Display should utilise multi-touch functionality for
interactions.

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