Unicast Performance Analysis of Extended ODMRP in a Wired-to-Wireless Hybrid Ad-Hoc Network

Sang Ho Bae

Sungwook Lee

Mario Gerla

UCLA Computer Science

{sbae, swlee, gerla}@cs.ucla.edu

ODMRP Overview Sources build routes on demand by flooding Update and maintain only active routes Less traffic overhead compared with proactive schemes Flooding overhead & longer delays because of route acquisition latency Developed on Linux version 2.2.12 with kernel level multicast support Running over IEEE 802.11 device (2.4 GHz) Implemented both unicast and multicast Wired to ad hoc wireless extension

Routing Example

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SS Join Query

Destination Nodes

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Join Reply

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Wired-to-Wireless Testbed

FTP server on top of Solaris 8 Wired-to-Wireless Gateway has 10/100 ethernet card and orinoco 802.11 pcmcia card Wireless nodes are Dell Inspiron 4000 laptops with 1GHz P3 running Mandrake 8.1 Linux Wireless channel with 2Mbps and RTS/CTS

Reference Experiment without Mobility

Wired to multihop wireless network with static route FTP from MR1 to CH (wireless one hop) FTP from MH to CH (wireless two hop)

MH : Mobile Host MR : Mobile Router WWR : Wire-to-Wireless Router IG : Internet Gateway CH : Corresponding Host

Reference Experiment Result

One hop Two hop

Avg. Throughput

1209.50 Kbps 626.89 Kbps

Less throughput than optimal bandwidth (1.59Mbps)* due to environmental noise and link condition Results depend on the signal strength Optimal locations are chosen for equal signal strength and multihop topology Avg. throughput for the two hop transmission ½ avg. throughput for the single hop

* Orinoco data sheet (given error rate < 10 )-5

Single Access PointExperiment

MH : Mobile Host MR : Mobile Router WWR : Wire-to-Wireless Router IG : Internet Gateway CH : Corresponding Host

Wired to multihop wireless network with dynamic routing FTP from MH to CH

Single Access Point Experiment Result

With mobility Without mobility

Avg. Throughput

671.98 Kbps 653.37 Kbps

Same topology with the reference experiment Routes are generated dynamically by ODMRP Routing overhead is negligible With mobility, avg. throughput increases due to the change of number of hops Packet loss due to route change triggers slow-start resulting in further reduction in throughput

Multiple Access Points Experiment

MH : Mobile Host MR : Mobile Router WWR : Wire-to-Wireless Router IG : Internet Gateway CH : Corresponding Host

Multiple Access Point Experiment Result

High Low Average

Avg. Throughput

1215.59 Kbps

920.54 Kbps

1050.55 Kbps

The results vary from trial to trial due to the link conditions between nodes In trial 1, immediate change from MR1 to WWR1 and remained in one-hop condition In trial 2, MH has been routed through MR1 and MR2 for the longer period of time Extended ODMRP can provide equivalent throughput as in static wired network with minimal overhead