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Ns SC546 Project (Fall 2002) SC546 Project (Fall 2002) SOO IL KIM - - PowerPoint PPT Presentation

Jun 12, 2023 124 likes •294 views

Ns Simulation of IEEE 802.11 Simulation of IEEE 802.11 Ns SC546 Project (Fall 2002) SC546 Project (Fall 2002) SOO IL KIM (kimsooil@bu.edu kimsooil@bu.edu) ) SOO IL KIM ( JISUN YOON (faithink@bu.edu faithink@bu.edu) ) JISUN YOON (

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Ns Ns Simulation of IEEE 802.11 Simulation of IEEE 802.11

SC546 Project (Fall 2002) SC546 Project (Fall 2002) SOO IL KIM ( SOO IL KIM (kimsooil@bu.edu kimsooil@bu.edu) ) JISUN YOON ( JISUN YOON (faithink@bu.edu faithink@bu.edu) )

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Project descriptions Project descriptions

  • Goals

Goals

  • Understand the IEEE 802.11

Understand the IEEE 802.11

  • Do wireless LAN simulations using Ns

Do wireless LAN simulations using Ns

  • Focus

Focus

  • Ad hoc networking

Ad hoc networking

  • Collision avoidance (RTS/CTS handshake)

Collision avoidance (RTS/CTS handshake)

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Wired vs. Wireless Wired vs. Wireless

  • Wireless communication

Wireless communication

  • No wired links: radio, infrared, laser

No wired links: radio, infrared, laser

  • Ad hoc network

Ad hoc network

  • Problems in Wireless Network (IEEE 802.11)

Problems in Wireless Network (IEEE 802.11)

  • No multi

No multi-

  • hop awareness

hop awareness

  • Hidden/ Exposed

Hidden/ Exposed

  • Unfairness

Unfairness

  • Packet drop is occurred often by errors in transmission layer

Packet drop is occurred often by errors in transmission layer

  • (Compare) Problems in Wired network

(Compare) Problems in Wired network

  • Major cause of dropped packets: Congestion in Routers

Major cause of dropped packets: Congestion in Routers

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Hidden/ Exposed node Hidden/ Exposed node

  • Data transmission from A to B

Data transmission from A to B

  • Hidden node =D (possibly Deaf node)

Hidden node =D (possibly Deaf node)

  • Cause packet collision

Cause packet collision

  • Exposed node=C

Exposed node=C

  • Prohibited from transmitting

Prohibited from transmitting

From “The deaf node problem in Ad hoc wireless LANs” by S. Ray, D. Starobinski, and J.B.Carrunthers

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

802.11 Operations (#1) 802.11 Operations (#1)

S R A C B 1 1 2 2 3 3 4 4 S R A C B S R A C B S R A C B

RTS RTS RTS CTS CTS CTS

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

802.11 Operation (#2) 802.11 Operation (#2)

  • Receive RTS

Receive RTS: Defer until CTS should have been sent : Defer until CTS should have been sent

  • Receive CTS

Receive CTS: Defer until Data should have been sent : Defer until Data should have been sent

  • If you don

If you don’ ’t receive CTS or ACK, back off and try it all over again t receive CTS or ACK, back off and try it all over again

(from http://www (from http://www-

  • ece.rice.edu/!ashu/reneclass/lectures/elec437lecture2.pdf)

ece.rice.edu/!ashu/reneclass/lectures/elec437lecture2.pdf)

A S R B C

RTS CTS Data Data Data ACK RTS CTS RTS CTS

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Ns (Network Simulator) Ns (Network Simulator)

  • A discrete event simulator targeted at

A discrete event simulator targeted at networking research networking research

  • The collaboration of USC/ISI, LBL, UCB, and

The collaboration of USC/ISI, LBL, UCB, and Xerox PARC Xerox PARC

  • Two main components: Ns, Nam

Two main components: Ns, Nam

  • Validation is needed

Validation is needed

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Ns Ns

  • Support wired/wireless models

Support wired/wireless models

  • Traffic models and applications

Traffic models and applications

  • Web, FTP, telnet, constant

Web, FTP, telnet, constant-

  • bit rate, stochastic

bit rate, stochastic

  • Transport protocols

Transport protocols

  • Unicast

Unicast: : TCP(Reno TCP(Reno, Vegas, etc.), UDP , Vegas, etc.), UDP

  • Multicast: SRM

Multicast: SRM

  • Routing and

Routing and queueing queueing

  • Wired routing, ad hoc routing and directed diffusion

Wired routing, ad hoc routing and directed diffusion

  • Queueing

Queueing protocols: RED, drop protocols: RED, drop-

  • tail, etc.

tail, etc.

  • Physical media

Physical media

  • Wired (point

Wired (point-

  • to

to-

  • point, LANs), wireless (multiple propagation models),

point, LANs), wireless (multiple propagation models), satellite satellite

  • Tracing, visualization using Nam

Tracing, visualization using Nam

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Ns Ns

  • Ns Programming

Ns Programming

  • C

Create the event scheduler reate the event scheduler

  • T

Turn tracing urn tracing

  • C

Create network reate network

  • S

Setup routing etup routing

  • I

Insert errors nsert errors

  • C

Create transport connection reate transport connection

  • C

Create traffic reate traffic

  • T

Transmit application ransmit application-

  • level data

level data

Using Ns (from http://www.isi.edu/nsnam/ns/ns-tutorial/)

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Environments/Configurations Environments/Configurations

  • set

set val(chan val(chan) Channel/ ) Channel/WirelessChannel WirelessChannel ;# channel type ;# channel type

  • set

set val(prop val(prop) Propagation/ ) Propagation/TwoRayGround TwoRayGround ;# radio ;# radio-

  • propagation model

propagation model

  • set

set val(ant val(ant) Antenna/ ) Antenna/OmniAntenna OmniAntenna ;# Antenna type ;# Antenna type

  • set

set val(ll val(ll) LL ;# Link layer type ) LL ;# Link layer type

  • set

set val(ifq val(ifq) Queue/ ) Queue/DropTail/PriQueue DropTail/PriQueue ;# Interface queue type ;# Interface queue type

  • set

set val(ifqlen val(ifqlen) 50 ;# max packet in ) 50 ;# max packet in ifq ifq

  • set

set val(netif val(netif) ) Phy/WirelessPhy Phy/WirelessPhy ;# network interface type ;# network interface type

  • set

set val(mac val(mac) Mac/802_11 ;# MAC type ) Mac/802_11 ;# MAC type

  • set

set val(nn val(nn) 4 ;# number of ) 4 ;# number of mobilenodes mobilenodes

  • set

set val(rp val(rp) ) AODV ;# routing protocol AODV ;# routing protocol

  • set

set val(x val(x) 800 ) 800

  • set

set val(y val(y) 800 ) 800

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Simulation #1 Simulation #1

  • Scenario

Scenario

  • Two fixed nodes

Two fixed nodes

  • moving within 600m x 600m flat topology

moving within 600m x 600m flat topology

  • DSR ad hoc routing

DSR ad hoc routing

  • TCP and CBR traffic

TCP and CBR traffic

  • Receiver move in and out of range

Receiver move in and out of range

  • Results

Results

  • Time vs. packets arrived

Time vs. packets arrived

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Simulation #2 Simulation #2

  • Scenario

Scenario

  • Two fixed pairs (4 nodes)

Two fixed pairs (4 nodes)

  • moving within 800m x 800m flat topology

moving within 800m x 800m flat topology

  • AODV ad hoc routing

AODV ad hoc routing

  • TCP and CBR traffic

TCP and CBR traffic

  • 2 nodes in each pair communicate each other

2 nodes in each pair communicate each other (hidden node) (hidden node)

  • Results

Results

  • Time vs. packets arrived

Time vs. packets arrived

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Simulation #3 Simulation #3

  • Scenario

Scenario

  • Six fixed nodes

Six fixed nodes

  • Change Routing algorithm

Change Routing algorithm

  • 4 Ad hoc routing: DSR/ DSDV/ AODV/ TORA

4 Ad hoc routing: DSR/ DSDV/ AODV/ TORA

  • The left

The left-

  • most node sends data to the right

most node sends data to the right-

  • most node

most node

  • Results

Results

  • Time vs. packets arrived

Time vs. packets arrived

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Further studies Further studies

  • Check the effectiveness of RTS/CTS handshake

Check the effectiveness of RTS/CTS handshake

  • Consider a lot of nodes in a small space

Consider a lot of nodes in a small space

  • More experiments using other traffic model (e.g.

More experiments using other traffic model (e.g. burst) burst)

  • Source

Source-

  • level (C++) modification for deeper

level (C++) modification for deeper understanding understanding

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

Useful links Useful links

  • Monarch project

Monarch project

  • http://www.monarch.cs.rice.edu

http://www.monarch.cs.rice.edu

  • (more links will be added on the web)

(more links will be added on the web)

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SC546 (Fall 2002) Ns Simulation of IEEE 802.11

That That’ ’s all s all

  • Thanks.

Thanks.