Shivkumar Kalyanaraman Rensselaer Polytechnic Institute 1 A Geography-Aware Community Wireless Testbed Bow-Nan Cheng, Max Klein Shivkumar Kalyanaraman

Shivkumar KalyanaramanRensselaer Polytechnic Institute

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A Geography-Aware Community Wireless Testbed

Bow-Nan Cheng, Max KleinShivkumar Kalyanaraman

Email: [email protected]

: “shiv rpi”

RPI, Troy, NY

Funding: NSF-ITR 0313095, Intel


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Outline

Wireless Ad-hoc Mesh Networks: Challenges Physical Layer: A “street-level” network Network Layer: Addressing Framework and Auto-

configuration Microcosm Test Bed Lab Future Work


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Community Wireless: What’s New?

Lots of work in ad-hoc networks coming to fruition Startup companies in the mesh networks space:

Tropic networks, Mesh networks etc

What’s different in CWNs? Why a testbed? Unmanaged, but operational network Ad-hoc, but operational Fixed (I.e. not mobile) Medium scale Supports organic growth and evolution Supports legacy internet traffic


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Community Wireless Networks: Challenges ? Why a Testbed?

Auto-configuration and auto-management: Only lightweight “governance” allowed Beyond addressing: routing, naming, other protocols

Higher quality than ad-hoc networks to support legacy applications (links, end-to-end transport)

Capacity maximization (c.f. Gupta/Kumar results) => routing choices, traffic engineering

Cheap, simple, standards-based components. New community apps (eg: p2p video, games).

Several nitty-gritty issues leading to new protocol design challenges… best researched in a testbed…


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Broadband exists. Why CWN? Ans: Multiplicity.

Cable modem and DSL and CWN and … Commodity => cheap to get multiple access facilities …

EthernetWiFi (802.11b)802.11a

USB/802.11a/b

Firewire/802.11a/b

Phone modem


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Physical Layer: Street-level vs Rooftop Leverage directionality and quasi-LOS

of streets => better quality links Omni-directional vs.

Directional Antennas

Eg:


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Antennas: Pringles cans disappoint

Cheap… But low gain:

6.01425 dBi


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COTS Directional Antennas

2.4 GHz 12 dBi Radome Enclosed YagiSuperior performance Light weight All weather operation 45° beam-width Can be installed for either vertical or horizontal Polarization. Includes tilt and swivel mast mount


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Network Layer: Addressing Goals:

IP-based architecture Support for geographic routing

Why? Medium-scale, Organic Growth, Location-services

Support for local traffic engineeringWhy? Dirn antennas, capacity maximization.

Support for distributed auto-configuration

Proposed Addressing Framework: Geographic Distributed Addressing (GDA)


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Geographic Distributed

Addressing (GDA)

Idea: Hash GPS -> IP address


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Why GPS-to-IP?

GPS-to-IP => Medium-scale, Server-less auto-configuration,

With routable addresses…

IP address has dual semantics: geographic and topological Long-range geographic routing/TE Short-range: (k-hop) topological RF-aware QoS routing … using the same IP/geographic address…

Location information also leveraged to auto-configure other L2/L3 protocols: Eg: cluster/area boundaries for routing, support location-based CWN

services


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Future: Geographic Source Routing

Source Routing

i.e. flex, large header

Greedy Routing

i.e. no header or state, but no flex

Trajectory-Based Routing

A

Q(t)

B

Trajectory defined as aparametric curveTBR route

Shortest-Pathroute

Gives us abilityto pick randomlyfrom a large number ofphysical routes


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Deployment Plan

Microcosm lab: internal prototyping, tests Logistics for long-term deployment around RPI

campus (eg: dealing with landlords etc) RPI-CIO providing access points at borders of campus

to help connect the CWN to RPI’s internal network


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Microcosm Test Lab

Variable attenuators, and directional antennas allow flexibilityin testing

We also intend to use public facilities like Utah’s Emulab Wireless


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Testbed Hardware… contd


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Testbed: Software

Fixed Nodes:- RedHat Linux Kernel 2.4.20-30.9- Click Modular Router: CVS March 5

Autoconfigured Nodes:- Redhat Linux 9: 2.4.20/21 Kernel- Click Modular Router: CVS March 5- HostAP 0.2 Driver + Utilities for

Firmware flashing- GPSD 1.10- DHCP Server + preconfigured NAT

w/ iptables ipmasq- Customized GSP Autoconf Scripts- Webserver + SSH in the future

-Intel Stargate/east platform will be considered as well


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Future Work GeoNet Framework to verify intersection between Geography

and Topological routing K-hop RF Awareness, QoS routing Distributed Geographic Traffic Engineering

Test Bed Improvements GPS Simulation Lab Reflectivity

Transport and application-layer activities kicked off Key: survival & quality under heavy erasure conditions. Collaboration ongoing with Intel and AT&T Research


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Vision #1: Multipath P2P Video/Data Over CWNs

“Fast” path

I

“Slow” path

P Traffic engineering &Transport level upgrades


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Vision #2: free-space-optical CWN

Ongoing NSF-STI project…


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Thanks!

: “shiv rpi”

Student Heroes: Bow-Nan Cheng: [email protected]

Max Klein: [email protected]

Documents

Shivkumar Kalyanaraman Rensselaer Polytechnic Institute 1 A Geography-Aware Community Wireless Testbed Bow-Nan Cheng, Max Klein Shivkumar Kalyanaraman