Slide 1

doc.: IEEE 802.11-06/0916r0

Submission

M-WLAN:A Layer-3 solution for Mesh Networking

Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.

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Date: 2006-07-14

Name Company Address Phone email Yuichi Murakami

Niigata University 8050 Igarashi 2, Niigata city, Niigata, Japan

+81-90-2441-3464 ymura@net.ie.niigata-u.ac.jp

Yasunori Owada

NiigataUniversity 8050 Igarashi 2, Niigata city, Niigata, Japan

+81-805475-3451 yowada@net.ie.niigata-u.ac.jp

Hiroei Imai

Niigata University 8050 Igarashi 2, Niigata city, Niigata, Japan

+81-25-262-7431 imai@ie.niigata-u.ac.jp

Mineo Takai

University of California, Los Angeles

3809 Boelter Hall, Los Angeles, CA 90095-1596

+1-310-825-4885 mineo@ieee.org

Kenichi Mase

NiigataUniversity 8050 Igarashi 2, Niigata city, Niigata, Japan

+81- 25- 262- 6755 mase@ie.niigata-u.ac.jp

Authors:

Slide 2

doc.: IEEE 802.11-06/0916r0

Submission

Self Introduction

• Niigata University

• IETF (Internet Engineering Task Force)

• MANET– OLSRv2 (Design Team)

– MANET auto configuration etc…

• M-WLAN– A Layer 3 solution for mesh networking

Slide 3

doc.: IEEE 802.11-06/0916r0

Submission

What’s M-WLAN

• M-WLAN : Multi-hop Wireless LAN• AP-AP : MANET• AP-terminal : Usual WLAN• M-WLAN can construct a mesh network

- 802.11a/b/g standard and MANET routing protocol are used- Layer-2 function is left unchanged.

AP AP

MANET

WLAN WLAN

AP: Access PointMS: Mobile Station

MS MS

Slide 4

doc.: IEEE 802.11-06/0916r0

Submission

What’s M-WLAN(2)

• Routing protocol : OLSR (UniK-olsr0.4.9)– Extension

• Association table– This table is used to decide the route to the mobile station.

• Associated Address Declaration (AAD) message– This message is used to exchange IP addresses of the mobile stations

between the APs and update their Association tables.

• IP address assignment to MS : DHCP

Slide 5

doc.: IEEE 802.11-06/0916r0

Submission

Routing Calculation

AP’s IPaddr MS’ IPaddr MS’ MACaddr

172.25.2.1 172.25.70.250 00:xx:xx:xx:xx:xxGW&

DHCP server

Internet

MS1

1.IP address assignment by DHCP

3.ＡＡＤmessage

2.Capturing DHCP Ack

Association table(AP1)

MAC : 00:xx:xx:xx:xx:xx

172.25.70.250

00:xx:xx:xx:xx:xx

4.Recalculating routing table

Association table(AP2)AP’s IPaddr MS’ IPaddr MS’ MACaddr

172.25.2.1 172.25.70.250 00:xx:xx:xx:xx:xx

IP : 172.25.70.250

AP2AP1

GW: Gateway

Slide 6

doc.: IEEE 802.11-06/0916r0

Submission

Roaming

MS1

3.ＡＡＤmessage

MAC : 00:XX:XX:XX:XX:XX

172.25.70.250

00:xx:xx:xx:xx:xx

2.Search MS’ MAC address fromAssociation table

IP : 172.25.70.250

1.Move & associate with new AP

4.Recalculatingrouting table

Association table(AP2)AP’s IPaddr MS’ IPaddr MS’ MACaddr

172.25.2.1 172.25.70.250 00:xx:xx:xx:xx:xx

172.25.2.2(AP2)

AP’s IPaddr MS’IPaddr MS’ MACaddr

172.25.2.1 172.25.70.250 00:xx:xx:xx:xx:xx

Association table(AP1)

172.25.2.2(AP2)

AP1 AP2

Slide 7

doc.: IEEE 802.11-06/0916r0

Submission

ARP message

MS1 MS2

MAC : 00:xx:xx:xx:xx:xxIP : 172.25.70.250

MAC : 00:yy:yy:yy:yy:yyIP : 172.25.70.245

AP’s IPaddr MS’ IPaddr MS’ MACaddr

172.25.1.2 172.25.70.250 00:xx:xx:xx:xx:xx

172.25.2.2 172.25.70.245 00:yy:yy:yy:yy:yy

Association table(AP1)

1.ARP request 3.Proxy ARP reply

2.Capture ARP request and refer to Association table

Request MAC address

corresponding MS2’s IP address

AP1 AP2

Slide 8

doc.: IEEE 802.11-06/0916r0

Submission

Inter-MSs communication & Internet access

GW&DHCP server

Internet

MAC IP

MS1 MS2

Layer 2

Layer 3

MAC IP

MAC IP

IP

From IM To IA

3.Extract IP packet from MAC frame and pass this packet to OLSR

1.Send MAC frame

4.Send data frame according to OLSR

IM : Interface that connects

AP with MSs IA : Interface that connects APs each other

AP1 AP2

2.IM capture all data frames (even if these data frames are not destined to itself).

Slide 9

doc.: IEEE 802.11-06/0916r0

Submission

Performance Evaluation

• We measured and checked– Throughput & RTT between MSs

– Access to the external network

– Handoff time

• We used M-WLAN test-bed for– Evaluating the capability of M-WLAN

Slide 10

doc.: IEEE 802.11-06/0916r0

Submission

Our M-WLAN Test-bed

3F

2F

1F

30m

9m30m: AP

Slide 11

doc.: IEEE 802.11-06/0916r0

Submission

Wireless Interface card x 2(MANET & WLAN)

Small embedded PC (AP)

AP

Power cable

Ethernet cable(For control)

Slide 12

doc.: IEEE 802.11-06/0916r0

Submission

Specification of Access Point

Name OpenBlockS

CPU IBM PowerPC 406GPr 266MHz

Built-in storage Compact Flash™1GB

OS Embedded Linux : SSD/Linux

(WLAN Interface)

Wireless LAN card

PCMCIA module

PLANEX GW-NS11H (802.11b)

hostap_cs

(MANET Interface)

Wireless LAN card

PCMCIA module

NEC WL54AG (802.11 a/b/g)

Orinoco_cs

AP-AP (MANET: backbone)802.11a

AP-MS (WLAN)802.11b

Slide 13

doc.: IEEE 802.11-06/0916r0

Submission

Evaluation (Throughput & RTT between MSs)

AP4 AP3

AP1

AP2

MS1

MS2

: DHCP server & GW (Laptop PC : One of the MANET nodes)

1 hop in MANET

MANET (backbone network)

• Performance metric : Throughput & RTT between MSs• Measurement environment

– 1 hop in MANET : MS1 -> AP1 -> AP2 ----------------------> MS2– 2 hops : MS1 -> AP1 -> AP2 -> AP3 ------------> MS2– 3 hops : MS1 -> AP1 -> AP2 -> AP3 -> AP4 -> MS2

Slide 14

doc.: IEEE 802.11-06/0916r0

Submission

Experimental parameter

Tool Ping

Hop count 1~3 (In MANET)

Interval 0.1sec

Number of packets 1000

Table.1 Experimental parameters for measuring throughput

Table.2 Experimental parameters for measuring RTT

Tool Netperf2.4.1

protocol TCP/UDP

Packet Size 1500byte

Hop count 1~3 (In MANET)

Number of measurement 10

Slide 15

doc.: IEEE 802.11-06/0916r0

Submission

Results (Throughput & RTT between MSs)

0

1

2

3

4

5

6

1 2 3

Hop count (backbone)

Thro

ughp

ut (M

bps)

UDPTCP

0

1

2

3

4

5

6

7

8

1 2 3

Hop count (backbone)

RTT

(ms)

RTT

Fig2. Inter MS Throughput Fig3. Inter MS RTT

• The effect of fading in the experimental environment causes the reduction of the throughput between AP2 and AP3.

• But this test-bed achieved more 2Mbps throughput in the case that the communication hops three times in MANET.

Slide 16

doc.: IEEE 802.11-06/0916r0

Submission

Evaluation (Access to external network)

AP4 AP3

AP1

AP2

MS1

: DHCP server & GW (Laptop PC : One of the MANET node)

1 hop in MANET

MANET (backbone network)

• Getting file from FTP server and measuring the throughput• Measurement environment

– 1 hop in MANET : MS1 -> AP1 -> GW --------------------->> FTP– 2 hops : MS1 -> AP2 -> AP1 -> GW ----------->> FTP– 3 hops : MS1 -> AP3 -> AP2 -> AP1 -> GW ->> FTP

: FTP server

Slide 17

doc.: IEEE 802.11-06/0916r0

Submission

Result (Access to external network)

Fig1. Throughput between MS and FTP server

0

0.5

1

1.5

22.5

3

3.5

4

4.5

1 2 3

Hop count (backbone)

Thro

ughp

ut (M

bps)

• I confirmed that this test-bed actually achieved smooth internet access in the case that the communication hops three times in MANET.

Slide 18

doc.: IEEE 802.11-06/0916r0

Submission

Evaluation (Handoff time)

• Performance metric : Handoff time• MS1 sends ICMP packet to MS2 by Ping, while moving.• MS1 deassociate from AP1 and associate with AP2.• The time of communication blackout was measured.

AP4 AP3

AP1

AP2MS1

MS2

move

Ping

Slide 19

doc.: IEEE 802.11-06/0916r0

Submission

Timeline (Handoff)

L-2 Handoff

L-3 Handoff

AAD Broadcast

Reassociation response

Reassociation request

Authentication (From AP)

Authentication (From MS)

Deauthentication

55ms

85ms

1ms2ms1ms2ms

13ms Report Association to L-3

Routing Update

Ping stop

Ping restart

Ｔｏｔａｌ140ms

Slide 20

doc.: IEEE 802.11-06/0916r0

Submission

Conclusions

• Conclusions– We designed and implemented M-WLAN.

• We constructed a Mesh Network -802.11 a/b/g standard was used. -L-2 function was left unchanged.

– We evaluated the performance of M-WLAN in our test-bed.• We presented

- the capability of M-WLAN. - a possible solution to the cause of lower performance.