UbiConn: Providing a Ubiquitous Connectivity Experience

Katherine EverittT. Scott SaponasSusumu Harada

December 6, 2004

Motivation

● Who DOESN’T use a wireless device?

● Proliferation of devices● Proliferation of services● Desire to be connected all

the time wherever you are

Current Network Technologies

● Wired (1 Gbps)● Wi-Fi (802.11a/b/g) (54 Mbps)● UMTS (300 Kbps)● EDGE (100 Kbps) GSM● GPRS (40 Kbps)

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What’s on the way…

● Wi-Max (802.16) (75 Mbps)– Targeted towards providing last mile broadband

access to businesses and residences– 3~5 mile radius– Mobile version (802.16e) not planned until 2006

● HSDPA (1 Mbps)– UMTS enhancement– Still being formalized

All Networks are not Created Equal

● Wired: Very fast, not mobile, point coverage● Wi-Fi: Fast, mobile, limited coverage● GSM: Slow, mobile, extended coverage● Combining Wi-Fi and GSM connectivity provides

“best” available service– Large coverage area– Access to high bandwidth whenever available

Do any of these technologies provide ubiquitous connectivity?

● Operating System attempts to connect to highest bandwidth connection available– Interruptions in connectivity– Only allows one connection to be active at a time– Some applications need a constant connection at

slow speed (GPRS)– Other applications want fastest connection available

(Wi-Fi)

● There will still be areas that have no wireless network coverage

Does ubiquitous connectivity exist?

● One might argue the “Savvy User” has an approximation of ubiquitous connectivity

● Savvy Users– Utilize resources like the hard disk to support

impoverished wireless resource– Practice manual caching– Switch to wireless technology

providing right class of service

Can we bring the experience of the savvy user to the average user?

● Simultaneously combine wireless technologies– When multiple connectivity options exist, give each

application the most appropriate service– IM/Terminal might utilize constant GPRS connection– Web browser would use largest bandwidth available

● Proactive caching for coverage gaps– Cache frequently accessed content– Utilize large bandwidth hotspots to refresh frequently

updated content

System Architecture

● Combining Wireless Technologies– Local HTTP Proxy– MultiAdapter (Windows 1:2 Mux Network

Adapter)

● Proactive Caching– Local HTTP Proxy– Content Classifier– Caching System

Evaluation

● Preliminary Evaluation of Caching System ● Scenario: CSE (WiFi) -> Eng Lib 1(None) ->

Eng Lib 3 (GPRS) -> CSE● Compared control to caching system

– caching system works as predicted– cellular networks had high variability

● MultiAdapter– Pending…

Future Work

● More sophisticated matching of applications to available types of network connections– Availability vs Bandwidth

● Explore use of cache for slow connections– For infrequently changed content– Tradeoff between freshness and speed.

Related Work

● Heterogeneous Networks – BARWAN– CHOICE Network– Coda– Rover

● Caching– Web Browser Caching – Long Term Prefetching– Edge Caching– Client Side Caching / Predictive Caching

● Multiple Simultaneous Links– Load Balancing Failover (LBFO)– SpeedBooster & Multi-Channel Wireless

● Mobile IP

Conclusion

● Mobile information access is important

● Used available resources to provide “savvy user” experience

● Simultaneous connections

● Proactive caching for coverage gaps

Thank you!

UbiConn: Providing a Ubiquitous Connectivity Experience

Katherine EverittT. Scott SaponasSusumu Harada