“WOMEN” Project Meeting Rome, Jan. 19th, 2007 1 UNITN Research Unit Status of the Work – First Year Fabrizio Granelli DIT – University of Trento [email protected]

“WOMEN” Project Meeting

Rome, Jan. 19th, 2007 1

UNITN Research Unit Status of the Work – First YearFabrizio GranelliDIT – University of [email protected]

“WOMEN” Project MeetingRome, Jan. 19th, 2007 2

UNITN role in the project Goal: “Performance Enhancement of Wireless

Mesh Networks and Testbed Implementation”

WP1 WP3

T3.4 Stream Control WP4

T4.5 Network Capacity Analysis WP5 (Resp.)

T5.6 (Testbed) (Resp.) T5.7 (Trials) (Resp.) O

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oin

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To define and validate an analytical model for connectivity and capacity of Wireless Mesh Networks, given design parameters n, r, l.

Traffic from/to mesh base station ≠ ad-hoc scenario

Network Capacity Analysis: goal

E. Miorando, F. Granelli, “On Connectivity and Capacity of Wireless Mesh Networks”, ICC 2007, accepted


Problem Statement

n → # nodes (random distribution)

S → squared area of dimension l x l

m → # access points r → comm range

nn → # neighbor nodes

nf → # forwarding nodes


Problem Statement• Single-cell analysis

→ squared area

→ m = 1

→ interfering nodes

• Traffic to/from BS

• Hyp.: → IEEE 802.11 CSMA/CA – RTS/CTS*

→ MFR routing

→ r = 250 [m]

* → “Performance Analysis of the IEEE 802.11 Distributed Coordination Function”, by G. Bianchi (JSAC, March 2000)


Connectivity analysis

No. offorwarding nodes*

Poisson distribution: λ = nf

!);(

k

ekf

k

fnfisol enfp );0(

* → “Optimal Transmission Ranges for Randomly Distributed Packet Radio Terminals”, by Takagi e Kleinrock (March 1984)


Connectivity analysis

hisolconn pp 1

*

apprd

Dh

dpd

dpd

l

D

disol

D

r

disol

appr

appr

2

12

0

2

12

0

)1(

)1(


• Bottleneck*

• Bottleneck collision domain*

Capacity analysis

30max

BG

G G G G G G G G

G 2G 3G 4G 5G 6G 7G 8G

1 2 3 4 5 6 7 8

GGGGGGB 3087654

* → “The Nominal Capacity of Wireless Mesh Networks”, by Jun e Sichitiu (Oct. 2003)


Capacity Analysis

Gn

n

n

n

n

nnnB

conn

connconn

2

1

11

3

12

ni → connected nodes at i-hops distance from the BS


Validation of the Approach

NS-2 simulator (v. 2.29) → C++ e OTcl No WMN support → WiFi@11Mbps

set tcp [new Agent/TCP]

$tcp set class_ 2

set sink [new Agent/TCPSink]

$ns_ attach-agent $node_(11) $tcp

$ns_ attach-agent $node_(19) $sink

$ns_ connect $tcp $sink

set ftp [new Application/FTP]

$ftp attach-agent $tcp

$ns_ at 100.0 "$ftp start"


Experimental Results: pconn

Averaged on 50 runs

variable nl = 2500r = 250

Max error:2,25 %

Avg. stdev:8,15 %

% connected nodes

0,00%

20,00%

40,00%

60,00%

80,00%

100,00%

0 2 4 6 8 10 12 14

# forward nodes

analysis

simulation


Experimental Results: Capacity

Averaged on 50 runs


Avg. error:17,53 %

Avg. stdev:22,85 %

Cumulative throughput

0

500

1000

1500

2000

2500

3000

3500

0 0,5 1 1,5 2 2,5 3 3,5 4 4,5

# forward nodes

[kbi

t/sec

] analysis

simulation

[kb

it/se

c]


Averaged on 20 runs


Avg. error:6,37 %

Avg. stdev:17,55 %

Averaged on 20 runs


Avg. error:15,51 %

Avg. stdev:22,15 %

Cumulative per-hop throughput (n = 100)

0

500

1000

1500

2000

2500

3000

3500

0 1 2 3 4 5 6 7

# hop

kbit/

s

analysis

simulation

Cumulative per-hop throughput (n = 200)

0

500

1000

1500

2000

2500

3000

0 2 4 6 8 10 12

# hop

kbit/

s

analysis

simulation

Experimental Results: Capacity[k

bit/

sec]


Conclusions

A first model for connectivity and capacity of WMNs was developed and validated

Good accuracy Points to consider:

Inter-cell interferenceHeterogeneous WMN (e.g. WiMAX+WiFi)Node movement (statistical model)


UNITN / CREATE-NET testbed


Testbed: where are we?

Started from Roofnet, making it device-agnostic:Monitor mode ad hoc modeLink quality evaluation using ETX

Roofnet on laptops works!Roofnet patch available on WOMEN website


Testbed: where are we?

Software porting to openwrt successful Automatic Gateway Discovery working Meraki (Roofnet spin-off) openwrt platform

freely availableClick in userspace running on 200MHz CPUs802.11 working in b mode

“WOMEN” Project MeetingRome, Jan. 19th, 2007

Click modules: Read RSSI, noise,

bitrate, etc. from incoming packet

Translate ingoing IEEE 802.11 packet into a Ethernet frame

Set rate and transmission power of the outgoing packet

Preamble management in Click


Change from monitor mode to ad-hoc mode (supported by any IEEE 802.11 NIC)

Introduction of an element for static setting of preamble parameters

link-quality evaluation using ETX

flags = 0;

power = 60;

rssi = 8;

rate = 2;

retries = 0;

“BlankDecap” module settings

Roofnet Modifications


SCHEDULER prototypes First prototype - COMPLETED:

Priority scheduling based (WRR) Works for TCP/UDP (2 hops test)

Second prototype – WORK IN PROGRESS: TRADE-OFF UTILIZATION/FAIRNESS Priority scheduling based (WRR) RED queuing policies (avoid drop-tail) ? Fairness idea: use deficit queues (one for each

service class) which provides FQ fairness Channel awareness ?

Channel measurements -> long implementation proper temporal scale to avoid fading and multipath

phenomena


Measurement platform (completed)

Set of bash scripts for:Automatic ssh key distribution among nodesTcp and udp bi-directional distributed measurements

(iperf) Throughput Jitter delay

Results collection and post-processingCan launch arbitrary unix commands on remote nodes


Dissemination activities - Papers

E. Miorando, and F. Granelli"On Connectivity and Capacity of Wireless Mesh Networks,“IEEE International Conference on Communications (ICC’07), Glasgow, Scotland, June 2007 (accepted).

D. Kliazovich, F. Granelli and D. Miorandi“Logarithmic Window Increase for TCP Westwood+ Improvement in High Speed, Long Distance Networks,”Computer Networks (submitted).

“WOMEN” Project Meeting

Rome, Jan. 19th, 2007 23

UNITN Research UnitFuture Activities

Fabrizio GranelliDIT – University of [email protected]


Activities in the 2nd Year

Finalization of Network Capacity Analysis Testbed Design:

Partially @CreateNet, partially @UniTN+ WiMAX-like long distance link

Frequency allocation @UniTN Testbed Implementation:

Second prototype design and programming Testbed deployment Tests on testbed Results collection and analysis

Documents

“WOMEN” Project Meeting Rome, Jan. 19th, 2007 1 UNITN Research Unit Status of the Work – First Year Fabrizio Granelli DIT – University of Trento [email protected]