Effect of latency on network and end user domains in Cloud Computing

Abstract

Cloud Computing is an on-demand access to a shared pool of resources. Vendor's of cloud computing provide application and enable technology, infrastructure, hardware, software, and integration for client. The flip side of the cloud computing is availability and performance of their internet connection [8]. If excessive network latency is causing the application to spend a large amount of time waiting for response from a data located at distant center, then the bandwidth utilization will not be properly done and performance will suffer. In our research paper, we have presented a practical approach to calculate the network latency which hampers the cloud performance and also in another section revealed the effect of DDoS attack on cloud computing with the simulated results.

Full text

Effect of Latency on Network and End User
Domains in Cloud Computing
Malvinder Singh Bali (Research Scholar)
Dept of Computer Science and engineering
CT College of Engineering and Technology, Shahpur
Jalandhar, India
mbali4964@gmail.com
Shivani Khurana (Assistant Professor)
Dept of Computer Science and engineering
CT College of Engineering and Technology, Shahpur
Jalandhar, India
shivani.khurana27@gmail.com
Abstract— Cloud Computing is an on-demand access to a shared
pool of resources. Vendor’s of cloud computing provide
application and enable technology, infrastructure, hardware,
software, and integration for client. The flip side of the cloud
computing is availability and performance of their internet
connection [8].If excessive network latency is causing the
application to spend a large amount of time waiting for response
from a data located at distant center, then the bandwidth
utilization will not be properly done and performance will suffer.
In our research paper, we have presented a practical approach to
calculate the network latency which hampers the cloud
performance and also in another section revealed the effect of
DDoS attack on cloud computing with the simulated results.
Keywords— Cloud Computing, Latency, Botnet, Performance,
Availability
I. CLOUD COMPUTING
Outsourcing of data center functionality and availability of
desktop application online via network connection is what
we term cloud computing [10]. Companies are moving to
cloud computing to cut down the I.T cost having the security
with less I.T staff. The expense has been cut down & traffic
of network has increased to double times. The big concern
for organizations depends on the availability of data,
quality of the network and their performance.
Primary motive behind more organization moving to cloud is
the reduction in cost and dynamic resource allocation. Since
the infrastructure is hosted by the cloud providers, software
enterprises do not need to worry about their maintenance.
Also, characteristics like Scalability, elasticity, Multi-
tenancy, pay-per use make cloud computing the most wanted
technology today.
A. How to use the Cloud
Simply log on to the sites that offer cloud facilities. To access
the cloud service, simply sign up and pay online if it is not
free,
DropBox.com, Zoho.com, Google docs.com are cloud sites
B. Services Offered
Email
Whether user uses Gmail, Yahoo mail or
Outlook.com, the email is stored on the cloud.
The front end website that you visit connects
you to the cloud where the data is stored
which is backend. Your email is send to the
nearest server.
File
Storage
Earlier we used to stored files on Floppy disks
and then went on to CD’s. Now storage is too
easy and cheap as it is on the web.Box.net or
Drop box stores files and helps you switch
easily between your laptop storage and “cloud
storage”
Sound
/Video
When you watch a video on YouTube you
have “cloud servers” at the back-end
streaming your favorite video. Sites such as
songspk.com and Mp3.com help us to listen
music for free in a similar manner.
Social
Media
Social media sites such as Facebook ,Twitter
or Google+ would have remained small and
localized affair if we did not have cloud
computing.
With strong networks, maximum routers and
high speed computers behind the scene and data
movement at the speed of light, social media
networks have become great example of cloud
computing and storage.
C Advantages
1. As long as you are connected to the internet, you can
access the cloud service and get to store data at very
cheap cost. Various sites do offer basic facilities free of
cost.

Basic facilities on paid sites cost around $10(500 rupee
a month)
2. Storing information in the cloud gives you almost
unlimited storage space. Hence; you no more need to
worry about running out of storage space or increasing
your current storage space availability.
3. Cloud computing gives you the advantage of
deploying application at a quick time, So as to make
user’s entire system fully functional in a matter of few
seconds.
4. Cloud service providers are usually competent
enough to handle recovery of information.Hence; this
makes the recovery and backup process much simpler
than other traditional methods of data storage.
D. Types of Cloud
1. Public Cloud- A public cloud is based on the
standard cloud computing model, where services like
infrastructure, application and storage are available to
the general public over the internet. Public cloud
services can be free or offered on pay-per usage.[11]
Example - Amazon Elastic Compute Cloud (EC2), Sun
cloud, Google AppEngine, and Window Azure
services.
2. Private Cloud- It is also called as Internal Cloud or
Corporate Cloud is a cloud set up within a corporate
organization that provides hosted services to a limited
number of people behind a firewall.[12]
Examples-Amazon Web services, VM Ware and Sales
force.com.
3. Hybrid Cloud- It is a cloud computing environment
in which an organization provides and manages some
resources in house and has others provided
externally.[13]
Example-IBM, Hewlett-Packard and EMC.
II. RELATED WORK/LITERATURE SURVEY
Adam Wolfe and Paul Lu [3] proposed a memcached named
Nahanni Memcached which can reduce the communication
overhead between Virtual machines(VM) located in same
server and used it with VDE networking to improve the total
read latency for a workload by up to 45%(i.e. read latest
workload) compared to standard memcached.
Ajith Singh and Hemalatha [1] conducted a survey on how
latency occurs in different geographical location and also
revealed an analysis work of how different browsers provide
different latency. A test conducted to show effect of
bandwidth reveals that when one tries to access cloud based
Google docs in cybercafé or GPRS connection it took 20 sec
while when tried to open at the campus of university which
provides 5.4 mbps it opens in 2 sec. The problem of latency in
the cloud network will be solved with the faster adaption of 3g
and 4g in the coming years.
Mohammad Haideri [2] tried to highlight the modelling and
simulation for different kinds of computer network attacks and
their impact on computer and networks. He explained
applications for modelling and simulation of computer
network security. It presents a comprehensive suggestion to
solve the problem in modelling and simulating in the field of
Information Security. He simulated the cloud network and
implemented the botnet attack on one of the cloud applications
i.e. FTP to analyze the effect of the attack on FTP server
Ankush Veer Reddy [4] proposed a security model for cloud
based applications by implementing a firewall using two
applications i.e. web based application and database
application to simulate and test the efficiency of the model.
Pardeep Sharma, Sandeep Sood and Sumeet Kaur [8] had
proposed the benefits of cloud computing along with its flip
side. This Paper also introduces various issues in Cloud
Computing and suggested the possible measures to overcome
them and the proposed algorithm is used to calculate and
compare the net revenue by using the cloud and data center
.
Sonia and Satinderpal Singh in [9] reviewed academic
research published in the field of energy efficient cloud
environment and aimed to provide an overview of analyzing
the energy consumption in different types of networks with
downloading/uploading speed and computing the performance
of networks.
Raihana Abdullah, Mohd Faizal Abdullah,Zul Azri
Muhamad,Mohd Zakri Mas Ud,Siti Rahayu Selamat and
Robiah Yusuf in [6] had addressed the current trend of Botnet
detection techniques and identifies the significant criteria in
each technique. Several existing techniques are analyzed
from various researchers and the capability criteria of botnet
detection techniques are analyzed. The techniques have been
shown on the selected detection criteria.
Ashraf Zia and Muhammad Naeem Ahmad Khan in [7] had
discussed performance issues in cloud computing. A number
of schemes pertaining to QoS issues are critically analyzed to
point out their strengths and weaknesses. Some of the
performances parameters at the three basic layers of the
cloud.IaaS, PaaS and SaaS are also discussed in this paper.
This paper also observed the key challenging areas that how
resources are allocated to clients and what are the roles of
cloud providers. Also investigated how the performance can
be increased by improving various components in a scalable
way with low cost, bitter performances and QoS. Some
technical and functional issues in cloud that affect the
performance of a cloud are also pointed out.
Nagaraju Kilari and Dr R.Sridaran in [5] had proposed
various security threats in a classified model and illustrated
how cloud and virtualization vulnerabilities affect the
different cloud models. The classification of various security

threats presented in this paper would definitely benefit the
cloud users to make out proper choice and cloud service
providers to handle such threats efficiently. As more cloud
based applications keep evolving the associated security
threats are also growing. Many researchers work on cloud
security exist in partial forms of either specifically on cloud
issues or Virtualization-related security issues
III. DOMAINS OF LATENCY FROM CLOUD TO END USER
Latency can occur in cloud area, in networks connecting
cloud to the end user and at the user end .Latency can be
measured by applying the formula abbreviations and Acronyms
A. Intra Cloud Latency
In cloud, latency can arise when two vm’s co-located on the
same server communicate with each other. This problem is
limited by introducing Nahanni memcached, a port of the
well-known memcached that uses inter-VM shared memory
instead of a virtual network for cache reads [1]. Facebook,
for example employs memcached as one of several caching
layers. .
B. Network Latency
Network latency cause applications to spend amount of time
waiting for responses from a distant data centre, then the
bandwidth may not be fully utilized and performance will
suffer [3]. Network latency is comprised of Propagation
delay, Node delay and Congestion delay .Good network
design can minimize node delay and congestion delay but not
propagation delay [9].
Network delay illustrates how much time it takes for a bit of
data to move across network from one node to another node.
 Propagation Delay- The amount of time taken for
head of signal to travel from sender to the receiver and
it can be defined as the ratio between link length and
the propagation speed over the specific medium
 Congestion Delay- Network congestion occurs when
a link or node is carrying so much data that its quality
of service deteriorates. Typical effects of congestion
delay include Packet loss, Blocking of new
connections and Queuing Delay.
C. Processing Delay
The processing delay is the time which routers take to process
the data. It is the important component in the network delay.
     
Fig 1.Diagrammatic Representation to estimate total network
Latency
In the above network diagram, consider the distance between
the two local area networks to be 200 miles and assume each
router adds 2ms.Current average network link utilization
without the storage application is 15%.So the amount of
bandthwidth available for new storage network application is
85% (i.e. 100%-15%).
The Distance between end points of network link is 200 miles.
Therefore Round Trip Time propagation delay is 200*2=400
miles or equal to 4ms.Also there are two routers in the path
taken by data. So the estimated round trip node delay is 2
nodes*2ms equal to 4ms.Now with congestion processing
delay, round trip node delay is increased to 4ms/0.85 equal to
5ms.Hence,total network latency(Propagation delay+ Node
delay+ Congestion delay) is 9ms(i.e. 4ms+4ms+5ms)
IV. PERFORMANCE MONITORING AREAS IN CLOUD
In cloud computing, Cloud service providers provide service
to cloud service consumers. Service Level agreements are very
important in cloud environment since the customer pays for
the services, infrastructure he uses [7]. Thus performance
monitoring of cloud should monitor the capability of
component of cloud in delivering expected services
A. Infrastructure Performance
Cloud service providers provide Virtual machines, Storage
network etc as infrastructure service and monitoring the
performance of these components is of paramount importance.
So a new approach called Infrastructure Response time is used
to get the performance of virtual cloud environment.IRT is
defined as the time it takes for any application to place a
request for work on virtual environment and for virtual
LAN
SAN
ROUTER
ROUTER
SAN
LAN

environment to complete the request. The request could be
simple data exchange.
B. Application Performance
It refers to the performance of applications hosted in the cloud.
The Application response time is key metric in application
performance monitoring which calculates the time taken for
any application to respond the user requests
C. Virtualization Performance
It is Similar to the physical machines and the performance
monitoring of Virtualization depends on the number of Virtual
machines used. Virtualization threats also hamper the cloud
performance [5].Other Parameters related to virtual machines
to measure the different performance metrics which include
 No of VMs used by the application
 Time taken to create a new VM.
 Time taken to move an application from one VM to
another.
 Time in which additional resources are allocated to
VM.
V. LATENCY AT THE USER END
On the other hand, how latency issues like service disruption
attacks at user end hamper the performance of cloud. For this,
a DDoS based attack (i.e Botnet attack)[6] has been applied on
existing cloud based model and performance has been
evaluated by analyzing the calculated results to see the overall
effect of attack on the cloud.
A. Proposed Architecture
In this section we have firstly created a normal cloud based
scenario [4] where we have taken two applications namely
database application and web based application. A workstation
of 10Base_T LAN object is used to act as the home office
supporting 150 work stations. Two PPP server objects are used
to act as database server and webserver.IP32_cloud object is
used to act as the internet cloud. The application configuration
object is used to define the application and the profile
configuration object is used to define the application profile.
Secondly we have implemented a firewall in the cloud based
scenario with one router acting as a firewall to do the function
of filtering. In the third scenario we have implemented a botnet
attack on the firewall based cloud scenario [2] by increasing no
of workstations from 150 to 250 with 150 users accessing
database
Fig 2.Normal Cloud Scenario
Fig 3.Firewall Security model
Fig 4.Botnet attack on Secure Cloud model
Table 1: Application description
Application
Attribute
Load
Database
Database
High Load
Web Browsing
Http
Heavy Browsing

Table 2: Simulated Parameters
Application
Parameter
Unit
Database
Traffic sent
Traffic received
Server DB Query
load
Throughput
Utilization
Bytes/sec
Bytes /sec
Requests/sec
Packets/sec
B. Methodology
The OPNET I.T Guru is used to build the network topology
of the cloud as described in fig 2.The cloud scenario used
across the simulation is done to evaluate the performance of
database cloud application by doing the comparative analysis
under three different scenarios using Botnet attack. For this a
cloud network topology is created, Statistics are chosen to
measure the performance, simulation is made to run and
finally results are analyzed based on simulation results.
VI. EVALUATION AND RESULT ANALYSIS
Fig 5. Database server Traffic Received (Bytes/sec)
In the above result, database server traffic in the form of
bytes/sec receives more bytes of data during botnet attack than
other two scenario’s causing congestion at the database server
end.
Fig 6. Database Server Traffic Received (packets/sec)
Similarly in the above graph, more number of packets are
received at the server end of database during botnet attack
causing heavy traffic as compared to normal and firewall
scenario where packets sent per second are less than botnet
scenario.
Fig 7. Point-to-Point Utilization (IP Cloud to Firewall)
In the above graph, Point-to-point throughput from IP cloud to
Firewall during firewall security was 70 packets per second
whereas during Botnet it was increased to 80 packets per
second.

Fig 8. Point-to-Point Utilization (IP Cloud to Router)
Point-to-Point Utilization from IP Cloud to Router during
Botnet scenario was 4 packets per second where as in other
two scenarios it is 2 packets per second on average
Fig 9. Point-to-Point Throughput (Database Server
to Router)
Fig 10. Point-to-Point Throughput (Router to Database Server)
VII. CONCLUSION
This paper highlighted the effect of latency on domains of
Cloud network and also presented the service disruption effect
due to DDoS attack on cloud network with simulated results.
For future work, we need to develop an Intrusion Detection
System so as to limit the effect of the attack on cloud network.
ACKNOWLEDGMENTS
The making of the paper needed co-operation and guidance of
all members of the department. I therefore feel privileged to
thank all those who have helped to make it successful. It is my
immense pleasure to express my Gratitude to Shivani Khurana
(Assistant Professor of Computer Science Department) as a
guide who provided constructive and positive feedback during
the preparation of the paper.
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