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https://sites.google.com/site/ensc427project/home
Team 11
Eric Swanlund
Paven Loodu
Sunny Chowdhury
1
Introduction
Technical Details: Network Layout and Overview
Performance Factors
Ns-2 Implementation
Simulation Throughput, Packet drop rate, average end-to-end
delay results in xgraph
Future Improvements
References
Roadmap
2
Who here doesn’t like Free Wi-Fi?
Motivation
3
That’s What I Thought
4
Very Popular/Common Wireless Technology
Results in a very high Speed Internet Connection
Also Known as WLAN (Wireless Local Area Network)
WLAN are based on IEEE ( Institute of Electrical and
Electronics Engineers
Can Connect Multiple Devices at the Same Time
SFU Connects at least 12,000 users in the middle of day
across its wireless network
Maximum Speed I found at SFU Wireless network was to
be around 95 Mbps at night but significantly comes down
around 55 Mbps during day
Real Motivation
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Used by everyone, with a majority of people not
knowing the actual architecture or underlying components that create a WiFi network
We want to gain a better understanding of not only how a WiFi network works but its performance when multiple users are transmitting data on the same network
We want to analyze our simulation results and determine what future improvements could optimize network performance
Real Motivation
6
Looked at some components of IEEE 802.11
NS-2 implementation along with description
Discussion on Further Improvements to Optimize Performance.
How Wireless Networks Work?
Physical Layer of OSI Model
Benefits are Cost Effective, Deployed Quickly, Extension Capability
Categories of Wireless Networks are: Wireless PAN, LAN, MAN, AND WAN
7
Introduction
Our wireless scenario involves two access points
where 2 mobile nodes are connected to one and 3 to the other
Network Layout and Overview
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9
Network Layout and Overview
The mobile nodes will upload data to the access points. The access points then pass the data packets to the wired node (which simulates the Internet) as shown,
The above network will be simulated using Network
Simulator version 2 (ns-2) to measure the throughput, packet drop rate, and average packets end to end delay
The nodes in the network will use IEEE 802.11 standards to communicate with each other
Two significant components of the 802.11 implementation are physical layer and MAC (Medium Access Control).
Network Layout and Overview
10
When evaluating a wireless network, throughput
and average delay are critical factors that determine the performance of the wireless network.
Throughput can be calculated by measuring the bytes received by a node
Packet drop rate can be calculated by determining the number of packets dropped by sink per unit time
Average packets end to end delay which is the time delay of the packets transferring from source to destination, divided by total packets received
11
Performance Factors
First, we defined options required for wireless
network simulation:
Channel type
Radio-propagation
Antenna type
Link Layer type
Interface queue type
Etc….
Ns-2 Implementation
12
The nodes in our network have specific functionality:
Wired node: main hub, connection for multiple LANs
Access points: represent wireless routers
Mobile nodes: users of the WiFi network
Ns-2 Implementation
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Ns-2 Implementation
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3 domains: 1 for wired nodes and 2 for access points
The mobile nodes are separated from other network components by using domains
Wired node belongs to domain 0
Mobile nodes 0 and 1 belong to domain 1 (access point 0), mobile nodes 2, 3, and 4 belong to domain 2 (access point 1)
Ns-2 Implementation
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UDP agents are attached to mobile nodes
Constant Bit Rate (CBR) traffic generators attached to UDP agents
Loss Monitors attached to wired node as sinks, in order to monitor bytes/packets received by sinks
CBR data rate set to 600 kbps
Packet size set to 512 bytes
Ns-2 Implementation
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Ns-2 Implementation
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Choose UDP instead of TCP since it’s faster and light
weight
TCP has reliability features such as flow control, three-way handshake, and error checking with recovery options; creates overhead at execution time
Ns-2 Implementation
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Measure throughput, packet drop rate, and average
end-to-end delay
Use xgraph to plot results
Simulation
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Throughput
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Packet drop rate
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Average end-to-end delay
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Dynamic Airtime Scheduling
Management of wireless network resources and convert a shared wireless network into a multi-service network infrastructure
Coded TCP
Removes packet loss by clumping blocks of packets together and transforming the blocks into algebraic equations
Missing data from messages is derived by receiver that solves equations in a linear manner
Future Improvements
23
[1] Almargni Ezreik, Abdalla Gheryani. “Design and Simulation of Wireless Network using NS-2”, Singapore, 2012. [2] Marc Greis, “Tutorial for the Network Simulator “ns”.” Internet: http://www.isi.edu/nsnam/ns/tutorial/index.html [Feb.
28, 2013]. [3] Jianping Wang, “ns-2 Tutorial Exercise.” Internet: http://www.cs.virginia.edu/~cs757/slidespdf/cs757-ns2-tutorial-
exercise.pdf [Mar. 2, 2013]. [4] Kevin Fall, Kannan Varadhan. (2011, Nov.) “The VINT Project.” Electronic [Online]. Available:
http://www.isi.edu/nsnam/ns/tutorial/index.html. [5] diffen.com, “TCP vs UDP.” Internet: http://www.diffen.com/difference/TCP_vs_UDP [Mar. 16, 2013]. [6] Mouhamd IBRAHIM, Giovanni NEGLIA, “Introduction to Network Simulator.” Internet” http://www-
sop.inria.fr/members/Giovanni.Neglia/ns_course/slides/lec4.pdf [ Mar. 16, 2013]. [7] J. Naoum-Sawaya, B. Ghaddar, S. Khawan, H. Safa Artail, H. Artail, and Z. Dawy, “Adaptive Approach for Qos Support in
IEEE 802.11e Wireless LAN.” Internet: http://hpds.ee.ncku.edu.tw/~smallko/ns2/wireless-udp-1.htm, Aug 2005 [Mar 18, 2013].
[8] Yue Wang, “ A Tutorial of 802.11 Implementation in ns-2.” Internet:
http://www.winlab.rutgers.edu/~zhibinwu/pdf/tr_ns802_11.pdf [Mar. 2, 2013]. [9] Aerohive Networks, “Wi-Fi Client Throughput—Maximized.” Internet: http://www.aerohive.com/solutions/technology-
behind-solution/maximizing-client-throughput [Mar 18, 2013]. [10] Extreme Tech, “Increasing wireless network speed by 1000%, by replacing packets with algebra.” Internet:
http://www.extremetech.com/computing/138424-increasing-wireless-network-speed-by-1000-by-replacing-packets-with-algebra [Mar 2, 2013]
REFERENCES
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QUESTIONS ?
25
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