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