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

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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

19

Throughput

20

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

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[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 ?

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