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Transcript
The Bay Area Research Wireless Access Network (BARWAN) Low-tier New Ideas • Wireless Overlay Internetworking – – – – – Satellite Regional Area High-tier “Overlay” IP extensions to Mobile IP Low Latency Inter-subnet Handoffs High Thruput Reliable Transport Class-Based Queuing Link Management Subnet Bandwidth Load Balancing • Client-Proxy-Server Architecture – – – – – Local Area Wide Area High Mobility Low Mobility R. H. Katz & E. A. Brewer, UC Berkeley Subcontractor: Hughes Research Labs Impact • Fundamental technology for 21st century battlefield communications: support for wide diversity of hybrid & asymmetric link technologies, and end device display & computation capabilities • Seamless roaming & application adaptation across 3–4 orders of magnitude of wireless b/w and latency (10 kbps to 10 mbps, 1 ms to 1 s) • Demonstrate network & application techniques able to scale to support 10s of data users/room, 100s/building, 1000s/facility, 10000s/metro, and 100000s/region Bandwidth-aware Data Type Adaptation Web & A/V Data Types over Wireless Proxy-Aware API, Kerberos Integration Delivery Class Abstraction Scalable Wireline Processing for Mobiles Schedule Measure & Eval Wireless Ovrly Technologies Aug 95 Start Demo in-building ovrlys & h/os with dynamic b/w alloc Aug 96 Demo wide-area ovrlys & low latency h/os w/ subnet load balancing Aug 97 Early Prototype Proxies (1-10 users) Proto Scaled Proxies (100-1000 Users) Initial Architectural Specification Scaled Architectural Specification Aug 98 End Scaled Proxies (1000-10000 Users) Large Scale Scalability Demonstrations 1 The Bay Area Research Wireless Access Network: Towards a Wireless Overlay Internetworking Architecture Satellite Regional Area Low-tier High-tier Local Area Wide Area High Mobility Low Mobility Randy H. Katz and Eric A. Brewer Computer Science Division, EECS Department University of California, Berkeley, CA 94720-1776 Subcontractor: Hughes Malibu Research Laboratories 2 Presentation Outline • • • • • • Retreat Purpose and Agenda Project Objectives, Motivation, Contributions Project Status and GloMo Demo Participation Review Project Plan New Directions Summary and Conclusions 3 Presentation Outline • • • • • • Retreat Purpose and Agenda Project Objectives, Motivation, Contributions Project Status and GloMo Demo Participation Review Project Plan New Directions Summary and Conclusions 4 Retreat Goals & Technology Transfer People Project Status Work in Progress Prototype Technology Early Access to Technology Promising Directions UC Berkeley Project Team Industrial Collaborators Reality Check Hughes Researchers Government Sponsors Feedback Friends 5 Retreat Purpose • To celebrate the completion of one project: BARWAN (Daedalus/GloMop) – Highlight the technical successes – Discuss the lessons learned • Kick off a new ambitious project: NINJA – Builds on experience in scalable processing platforms (NOWs), agent architectures, ubiquitous connectivity, multimedia toolkits – A middleware-intensive approach to “active networking” – User-centered applications: » Computer-telephony integration and services » Personal information management » Smart spaces • Form new industrial consortium for technical follow on 6 BARWAN/Hughes Team • Networking – Hari Balakrishnan (Reliable Transport) – Tom Henderson (Satellite-based Transport & Routing Protocols) – Todd Hodes (Service Discovery) – Giao Nguyen (Channel Scaling) – Venkat Padmanabhan (Sessions-Transport Interface) – Mark Stemm (Performance Discovery) – Helen Wang (Vertical Handoff) • Hughes Malibu Research Laboratory – Son Dao – Yongguang Zhang – Dante De Lucia • Applications – Yatin Chawathe (Proxy Architecture/MASH) – Armando Fox (Proxy Architecture) – Steve Gribble (Scalable Servers) • Technical Support – Brian Shiratsuki (System Admin) – Keith Sklower (Sys Programming) • Admin Support – Terry Lessard Smith – Bob Miller Srini Seshan got his PhD and is a researcher at IBM Research Elan Amir got his PhD and is starting a company Tao Ye finished her MS and went to JavaSoft Daniel Jiang went to Daimler Benz Research Laboratory Hari Balakrishnan will be an Assistant Professor at MIT Armando Fox will be an Assistant Professor at Stanford Venkat Padmanabhan is considering offers from leading industrial research labs 7 BARWAN Sponsors and Participants • DARPA GloMo Program – Rob Ruth, DARPA PM – Kevin Mills, DARPA PM/NIST – SRI • Industrial Supporters – – – – – – – Daimler Benz Ericsson (Reiner Ludwig, Visiting Industrial Fellow) Fuji Xerox Palo Alto Labs HRL (Hughes/Raytheon) IBM Metricom Toshiba (Masahiro Takagi, Visiting Industrial Fellow) • Friends – Lucent, Motorola, Packeteer, Philips, Rutgers, Sandia, Sprint 8 Retreat Schedule • Wednesday, June 10: 0800 - 1130 1200 - 1330 1330 - 1430 1430 - 1630 Travel from Berkeley to Granlibbakkan Lunch Project Overview and Retrospective, Randy Katz Senior Student Research Talks: Transport Issues » Hari Balakrishnan: “Challenges to Reliable Data Transport Protocols over Heterogeneous Wireless Networks” » Venkat Padmanabhan: “Addressing the Challenges of Web Data Transport” 1630 - 1830 Break 1830 - 1930 Dinner 1930 - 2030 Senior Student Research Talks: Proxy Architecture » Armando Fox: “Building Scalable, Composable, Adaptive Internet Services With TACC” 2030 - Distributed Interactive Collaboration (aka Riven) 9 Retreat Schedule • Thursday, June 11: 0730 - 0830 Breakfast 0830 - 1030 Recent Progress Presentations » Mark Stemm: “Benefits of Content Negotiation in HTTP” » Tom Henderson: “Datagram Routing for Next Generation Satellite Systems” » Giao Nguyen: “Channel Dependent Link Scheduling” » Yatin Chawathe: “Proxy Load Balancing” 1030 - 1100 Break 1100 - 1200 Ninja Overview, Eric Brewer 1200 - 1600 Lunch/Long Break 1200 - 1400 Special Faculty/Sponsor Meeting* * to discuss opportunity to establish an Internet Systems Research Group at Berkeley 10 Retreat Schedule • Thursday, June 11: 1600 - 1900 Ninja Mini-Retreat, Eric Brewer » I-Space: Steve Gribble, Mark Stemm, Matt Walsh » ICEBERG Architecture: Anthony Joseph, B. R. Badrinath » Multi-Formfactor Documents using XML: Todd Hodes » Service Discovery and Path Creation: Eric Brewer » Code Transformation: Steve Gribble 1900 - 2030 Dinner 2030 - 2200 Poster Session 2100 Distributed Problem Solving Ninjutsu is a stealth and espionage-oriented art which saw its greatest development in the 13th to early 17th centuries in Japan. Its practitioners, the ninja, were warrior-assassin-spies; most belonged to the Iga and Koga mountain clans. They were the supreme reconnaissance experts and saboteurs of their day. 11 Retreat Schedule • Friday, June 12: 0730 - 0830 0830 - 1000 1000 - 1030 1030 - 1200 1200 - 1300 1300 - Breakfast Six Month Planning Session, Anthony Joseph Break & Check-out Sponsor/Friends Feedback Session, Randy Katz Lunch Depart Granlibakkan 12 Presentation Outline • • • • • • Retreat Purpose and Agenda Project Objectives, Motivation, Contributions Project Status and GloMo Demo Participation Review Project Plan New Directions Summary and Conclusions 13 Heterogeneous Mobile Computing “People and their machines should be able to access information and communicate with each other easily and securely, in any medium or combination of media -voice, data, image, video, or multimedia -- any time, anywhere, in a timely, cost-effective way.” G. Heilmeier, 1992 • • Access Anytime, Anywhere – Wide-Area Coverage – Scalable Processing – Highly Available Operation • • Three Overarching Strategies: – Heterogeneous Wireless Networks – Network Optimization – Dynamic Adaptation Easily – Transparent Access – Localized Service • Securely – Global Authentication • Any Medium – Multimedia: Audio/Video/Graphics • Timely – Performance • Cost Effective – Heterogeneous Support via Proxies 14 Mobile Applications “Sessions” Proxy Agents Transport (Asymmetric, Heterogeneous, Lossy Links) Overlay IP (Mobile IP + Overlays) Snoop Agent Link Scheduling Net Connection Monitoring; Net-Appl Interface; ELN; Wireless LAN Location-Dependent Services Daedalus/GloMop Architectural Components IP Wire- DBS Packet Less SubRadio Cable Net Cellular Data ATM SubNet Mobile IP Beacons 15 Daedalus/GloMop Architecture Basestations Horizontal Handoff Foreign Agent Server (Correspondent Host) Local Proxy Host G W GW G G W G W W Local Services Vertical Handoff Proxy Host IP Internet GW Overlay IP GW Wireless Subnets Home Agent 16 Problems Solved by Daedalus/GloMop Archtecture • Seamless mobility within and across heterogeneous networks – Transparent and automatic network connections – Low latency handoffs yielding smooth audio and video while roaming • Reliable transport based on TCP – Interoperation with legacy servers – Hides performance losses due to wireless losses, asymmetries • Automatic discovery and configuration of local network services – Universal remote control with dynamic UIs 17 Problems Solved by Daedalus/GloMop Archtecture • Thin Client Support – Dynamic adaptation of content – Computational support in the infrastructure for resourcepoor clients • Scalable Infrastructure Services – Cluster-based computing – Scalable, extensible, available – Layered programming model for new service creation 18 Wireless Overlay Networks Regional-Area Theatre of Operations Metropolitan-Area Rear Echelons Campus-Area Packet Relay Bases, Depots, Ranges In-Building Command Centers Training Centers 19 Major Contributions • Overlay Networking and Vertical Handoff – Design Constraints » Low Latency Handoff » Power Conservation » Bandwidth Conservation – Handoff Mechanisms » Modified Mobile IP (“Overlay IP”) » Local-Area Multicast for Low Latency Horizontal H/O » Fast Beaconing, Header Doublecasting for Vertical H/O » Policy-based Vertical H/O 20 Asymmetric & Heterogeneous Access High Bandwidth – Command Post – Disaster Relief – Remote Clinic – Organization w/poor Internet connectivity Low Bandwidth Local Subnet 21 Major Contributions • Reliable Data Transport over Wireless Networks – Wireless Packet Losses » Snoop Protocol: agent-based approach for local retransmission – Asymmetric Networks » Sources of asymmetry: bandwidth, latency, losses » Managing the ACK stream while maintaining good pacing of data packets • • • • • Ack congestion control Ack filtering Ack reconstruction Sender adaptation Acks-first scheduling – Link Sharing for Wireless LANs, Cable Model Nets, GPRS » Class-based queuing plus channel-state dependent packet scheduling 22 Client-PROXY-Server Architecture • Proxy – – – – Mediates between wireless and wireline environment Ideally executes at “well-connected” boundary of internetwork Manages caches and chooses transport data representations on-the-fly Trade transcoding time against communications time Well Connected Proxy Poorly Connected 23 Major Contributions • Proxy Architecture – Adaptation to variation in hardware, software, and network capabilities of end devices » Thin client display and processing limitations » Network connectivity and security processing limits – On-Demand Image Transformation » Web browsing with graphics on PalmPilot » Postscript viewing on PDAs via on-demand transformation to HTML – Real-time Video Transcoding » MBone video over ISDN, transcoded from 400 kbps to 128 kbps » Multicast-based white-board sessions on the PalmPilot 24 $ $ $ Cache control Scalable Proxy Architecture To Internet NOW Cluster SAN (high speed) Utility (10baseT) Coordination bus html Front End gif PTM jpg Control Panel $ Cache partition ... Datatype-specific distiller Major Contributions • Proxy Architecture – Measuring changes in network characteristics: SPAND » Piggyback measurements on top of existing traffic » Share performance information among user community – Scalable cluster-based proxies » NOW Platform/Scalable Network Service • Load balancing, availability/fault tolerance, system monitoring/logging » TACC (Transformation, Aggregation, Caching, Customization) Programming Model • Composition of stateless data transformation and content aggregation modules • Caching of original, post-aggregation, post-transformation products » Service • Workers providing control interfaces and presentation of TACC modules 26 Key Research Themes • • • • Dynamic Adaptation Cross-Layer Optimization Agent-Based Processing Soft State 27 Key Research Themes • Dynamic Adaptation – Varying network conditions » Adaptive mechanisms for TCP » Channel dependent class-based queuing » Vertical handoff – Client and network heterogeneity » On-demand format conversion » Real-time video transcoding based on network conditions » Dynamic quality/performance tradeoffs » Dynamic generation of customized UIs for small devices 28 Key Research Themes • Cross-Layer Optimization – Explicit violation of OSI protocol stack » Physical layer quality information to trigger handoffs » Handoff information to trigger application-layer adaptation » Transport layer information to trigger link layer retransmission » Explicit link layer loss vs. congestion loss information to drive sender adaptation » Network-level performance information allows applications and proxies to tune content 29 Key Research Themes • Agent-Based Processing – Method by which new capabilities can be inserted into the network » Agents break end-to-end connections, enabling introduction of new protocols/formats/processing while still supporting legacy end points – Network » Mobility agents for vertical handoff » TCP processing agents to deal with losses and asymmetric connections – Applications Support » Proxy agent » Real-time gateway agent 30 Key Research Themes • Soft State – Definition: any state that aids performance, adds capabilities but is not essential for correctness – Major advantage: tremendously simplifies recovery – Extensively used in all elements of the agent architecture » Snoop Agent • Soft state cache of recent unacknowledged TCP packets • Permits local retransmission without violating TCP’s end-to-end semantics » TCP Fast Start and Sessions • Use recently cached connection state to “fast start” new connections » SPAND Performance Database » TranSend Proxy • Distillation caches • Worker soft state eases recovery and load balancing 31 Major Software Artifacts • TCP Snoop Agent • Low-latency Horizontal Handoff • Vertical Handoff • TCP SACK (Selective Acknowledgement) • STP (Satellite Transport Protocol) • SPAND Performance Server • Service Discovery Services and Remote Control in Soda Hall • rtpGW: Real-time protocol gateway for A/V • Pythia Proxy Server • TranSend Scalable Proxy Server • TopGun Wingman Browser for PalmPilot • TopGun MediaBoard • Charon Indirect Authentication • Various software developer kits • ns/VINT simulation models 32 Technology Transfer • Proxy Software – Beta TranSend binary distribution available » Distributed to UC Davis, SRI – Wingman Pilot Browser: 8000 downloads – Postman Pilot E-mail: 6000 downloads – “Professional” distribution from Proxinet, Inc. • RTP Gateway – 171 downloads in 1997 • Transport Layer Software – 100 snoop V1 downloads » Linux, FreeBSD, NetBSD ports – 222 SACK downloads » Ports to NetBSD – snoop in daily production use in Reinas wireless network@UCSC • Wireless, LAN MAC, and Transport simulation modules widely distributed to VINT community – HTTP simulator module for ns: 232 downloads – STP simulation scripts for ns: 69 downloads 33 Presentation Outline • • • • • • Retreat Purpose and Agenda Project Objectives, Motivation, Contributions Project Status and GloMo Demo Participation Review Project Plan New Directions Summary and Conclusions 34 Project Plan and Status 90% Project Start: 15 Aug 95 (Start + 34 Months) Scalability Scalability 100% Demonstrate via Simulation Ability to Scale to Large Communities of Mobile Users Functionality Functionality 100% Early Early Proof Proof of of Concept Concept Implementations Implementations Demonstrate Seamless Roaming over Local and Wide Area NOWs Local & Wide-Area Wireless Overlays Enhanced E2E Performance Establishment of of Establishment BARWAN Testbed Testbed BARWAN 100% Measure Alternative Overlay Network Performance Extend with Emerging Technologies 35 BARWAN Testbed DirecPC DBS (1 mbps) Vertical Hand-Off LOS Wireless Cable (6 mbps) DARTNet II CAIRN 10-30 kbps Metricom Cellular Modem Cellular Packet Data Packet Radio Plus local area RF and IR nets in Soda Hall 36 Military JTF Application-Oriented Demonstration: July 98 DBS Uplink Reachback LEO Forward Area 2 Forward Area 1 Rear Area BDE BN RDMP Receive Metachannel Client Geofiltering GeoEmail FreeBSD Bengal DB Win 95 RDMP Send Metachannel Server Georouting Sender GeoEmail Image Server FreeBSD ASAMA Net ASAMA Hub RDMP Receive Metachannel Client Geofiltering GeoEmail FreeBSD Uplink SAMA Reacback Net (LEO) SAMA Control VXWorks Video GW BSDi LEO Emulator FreeBSD RDMP Receive Metachannel Client Geofiltering GeoEmail FreeBSD Bengal DB Win 95 DBS Emulator FreeBSD BN BDE Bengal DB Win 95 RDMP Receive Metachannel Client Geofiltering GeoEmail FreeBSD Bengal DB Win 95 Soldier Phone Net Bengal DB Win 95 37 XX Bengal DB DBGlomo Win 95 1 NTSC Audio X XXXX JTF 1 DBS Emulator 1 ARFOR RDMP Send Metachannel server Resource scheduler MASH Georouting sender Image server Web server Video Gateway SAMA Control (LEO Emulator) FreeBSD FreeBSD 10Base T Hub 10 Base T Hub 10 Base T Hub A FreeBSD V MASH Geonode/Geohost XGloMo BSDi VXWorks Local RDMP RDMP Proxy Metachannel client Web browser Video Gateway (H.261-H.261) SAMA Hub 915 MHz (12 kbps/ch Reachback Win 95 SAMA Tx Bengal DB DB GloMo Soldier Radio Geolocation 1 1st BN Net 1 Soldier Radio Soldier Radio Downlink To 2nd BDE 1 Bengal DB DB GloMo 10 Base T Win 95 10 Base T FreeBSD A V Geolocation 2 Local RDMP Metachannel client Web browser MASH Geonode XGloMo 38 Downlink From 1st Division X 2 1 MARFOR Bengal DB DB GloMo Win 95 SAMA Tx FreeBSD Local RDMP RDMP Proxy Metachannel client Web browser A V MASH Geonode/Geohost XGloMo 10 Base T Hub Video Gateway (H.261-H.261) 2 2 Bengal DB DB GloMo Win 95 ASAMA Control and ALOHA Multi-sensor Simulation Win 95 ASAMA Rx (PCI card) CW Jammer 2nd BN Net 915 MHz (4 kbps/ch) ASAMA Tx (PCI card) A FreeBSD V ASAMA Tx (PCI card) Local RDMP Metachannel client Web browser MASH Geonode/Geohost XGloMo Geolocation 3 39 Military RDF Application-Oriented Demonstration: July 98 CO BN BN DirecPC Wireless ATM CO CO Disconnected Operations Original affiliation New Affiliation CO Browser GeoFilter GeoEmail FreeBSD Coda Server FreeBSD Snoop BSDi DirecPC BSDi DirecPC RDRN ATM Net MMWN Net Special Gateway Security Solaris Browser GeoFilter GeoEmail FreeBSD Wings Net W Security Solaris Coda Client FreeBSD Edge Node Linux Edge Node Linux Special Gateway Coda Server FreeBSD W Geofilter GeoEmail Linux Web Proxy GeoFilter GeoEmail Linux Security Solaris W W W Coda Client Browser GeoFilter GeoEmail FreeBSD W Security Solaris Wings Net W W Geofilter GeoEmail Linux W Coda Client Browser GeoFilter GeoEmail FreeBSD W Wings Net W Security Solaris Geofilter GeoEmail Linux W Coda Client Browser GeoFilter GeoEmail FreeBSD 40 Presentation Outline • • • • • • Retreat Purpose and Agenda Project Objectives, Motivation, Contributions Project Status and GloMo Demo Participation Review Project Plan New Directions Summary and Conclusions 41 Six Month Plan (to June 98) • Documentation • Link Layer “A Network Architecture for Heterogeneous Mobile Computing” paper Final architecture document (final clean up stages; released at August end of project) • – STP Specification (in progress) Proxy SDK completed SPAND SDK Released – BARWAN all-inclusive CD-ROM (August end of project) • Testbed Integrate and Evaluate GSM Add SPAND performance server – Implementation of priority-based link sharing (deferred) Simulation studies of cable modems (802.14) Simulation studies of GPRS Transport Evaluation & implementation of TCP sessions and fast-start mechanism Measurements of asymmetric TCP and simulation of alternative lossrecovery mechanisms for Ricochet STP implementation released 42 Six Month Plan (to June 98) • High Level Networking (Initial) design policy-based vertical handoff (completed implementation by August, under continuing industrial sponsorship) Clients that use SPAND to tune proxy adaptation More sophisticated and extensible SPAND performance server (Initial) wide-area service advertisement design (inprogress) Extend co-lab testbed (RVic, Camera control) • Proxy/Application Support – Complete MediaBoard (inprogress; complete by August) Thin-client partitioning strategy – Production versions of new services (in-progress) – HTTP content negotiation (abandoned in favor of XML-based metadata schemes) Secure proxy services (secure client-links done at Proxinet) 43 Original Research Plan Year 1 Year 2 Year 3 T1: Overlay Inter network Management Ser vices Measure & Eval Ovly Nets Design f or Wide-Area Ovly Demo Wide-Area Ovly Design f or In-Building Ovly Demo In-Building Ovl y Net Demo Scaled Net Perfor T2: Mobile Application Support Services Design API & App lToolkit Demo API for In-Building Integrate with NOW Servers Develop Simple Colla b App s Demo Scaled App s Perf O1: Wide-Area Deployment and Demonstr ation Acceler ate Design f or Wide- Demo Wide-Area Overla y Area Ovly Integration Design f or Multiple Ovly s O2: Pilot Application Demonstr ations Large Scale Demo of Na v Deploy In-Build Net@UCSF Design Libr Na v & Med Eval Med Image App s Reqs Image Distr App s using API & Med Image Distr App s 9/95 - 8/96 9/96 - 8/97 Demo Extension to Multip le Wide-Area Overla ys 9/97 - 8/98 44 DARPA GloMo Program Goals DARPA GloMo FY 96 Daedalus/BARWAN Program Adaptive Mobile Internet Services Measure/eval overlay networking tech Design overlay network architecture Design proxy architecture, API, toolkit Prototype proxies for image, video, maps Location Transparent Computing FY 97 Demo B/W Adaptive MM Node Design Scalable Proxies/Proxy Trans Mgr Arch for “Remote Collaboration by Proxy” Demo Advanced Mobile Networking Overlay IP and Vertical Handoff Reliable transport for hetero/asym nets FY 98 Demo Multimedia Conferencing Demo Continuous Mobility Demo scalable processing for proxies Demo seamless roaming over in-building, wide-area wireless overlays 45 Revised Project Schedule Measure & Eval Wireless Ovrly Technologies Aug 95 Start Demo in-building ovrlys & h/os with dynamic b/w alloc Aug 96 Demo wide-area ovrlys & low latency h/os w/ scalable performance Aug 97 Early Prototype Proxies (1-10 users) Proto Scaled Proxies (100-1000 Users) Initial Architectural Specification Scaled Architectural Specification Aug 98 End Scaled Proxies (1000-10000* Users) Large Scale Scalability Demonstrations * on 10 UltraSparc cluster 46 Milestones to End of Contract • 3Q97 Final Architectural Specification Integrated wireless simulation environment based on ns • 4Q97 Demonstration of network scaling in simulated WLAN environment Demonstration of network scaling in simulated PR environment • 1Q98 Demonstration of scalable, extensible TACC (Transformation, Aggregation, Customization, Caching) Servers • 3Q98 – Integrated demonstration of wireless networking, real-time conferencing, proxy adaptation, integrated into GloMo “Eye Watering Demo” – Participate in July DC Demonstration 47 What We Proposed to Do Completed In-Progress 48 What We Proposed to Do • Seamless integration of overlay networks – Handoff » Low latency handoff via user tracking » Vertical handoff (power vs. latency) » Policy-based VHO (Helen Wang this summer) – Transport » TCP over high error rate links (snoop) • Support services for mobile applications – Data type specific compression (proxy distillation) and progressive transmission – Dynamic applications partitioning across wireless links (service discovery and adaptation; wingman browser) – Integration of multimedia and web applications with wireless environment (vic/vat, browser) 49 What We Proposed to Do • Managing mobile connections to support latency-sensitive applications – Link scheduling, class-based queuing – Real-time stream adaptation (RTP gateway) • Load balancing for scalable mobile processing – Network load balancing across overlay networks – Network servers to support processing and storageintensive applications (NOW integration/TranSend) – Uniform architecture for applications support (TACC programming model ) 50 Beyond the Proposal • Research Infrastructure – VINT-based simulation environment – Mobile and home IP trace collection • Asymmetric Transport – TCP enhancements for bandwidth, latency, error asymmetries in PR, wireless cable, DBS subnetworks – Satellite Transport Protocol • Active Services Architecture – RTPGateway’s evolution into MediaGateway – Service discovery and adaptation • Scalable, Composible Service Architecture – TACC model – PalmPilot WingMan Browser 51 Presentation Outline • • • • • • Retreat Purpose and Agenda Project Objectives and Motivation Project Status Review Project Plan and Contributions New Directions Summary and Conclusions 52 Project Synergies BARWAN Wireless Overlay Networks Scalable Proxies vic, vat, wb TranSend TACC Model Wireless Access NINJA Scalable, Secure Services Computation in the Network “Smart Spaces” as an app Event-Response Programmable Access RTPGateway Service Discovery MASH Collaboration Applications Active Services MASH Toolkit Active Services Model NOW/Millennium Computing Platform 53 Emerging Distributed System Architecture Spanning Processing and Access Personal Information Management and “Smart Spaces” Distributed Videoconferencing Room-scale Collaboration Speech and Location Aware Applications ICEBERG Computer-Telephony Services MASH Media Processing Services Active Services Architecture TranSend Extensible Proxy Services Distributed Computing Services: Ninja Computing and Communications Platform: Millennium/NOW 54 Experimental Testbed Fax IBM WorkPad Image/OCR Text Speech MC-16 Ericsson CF788 306 Soda Motorola Pagewriter 2000 WLAN 405 Soda 326 Soda “Colab” Pager GSM BTS Network Infrastructure Millennium Cluster Smart Spaces Personal Information Management Millennium Cluster 55 Presentation Outline • • • • • • • Retreat Purpose and Agenda Project Objectives, Motivation, and Approach Project and Testbed Status Technology Developments Review Project Plan New Directions Summary, Lessons Learned, Conclusions 56 Summary • A complete network and application support architecture for access across lossy links from a wide variety of end devices • Access is the killer app – Seamless connectivity through wireless overlays – Adaptivity through proxy services • Heterogeneity, asymmetry, adaptation – Asymmetric bandwidth in satellites, cable modems, cellular systems: new transport protocol techniques – High loss links: achieving high bandwidth utilization through local intelligent retransmission – Adapt representations to the quality of the end device and its network connectivity: proxies for audio/video streams and imageful web documents 57 Lessons Learned • Architectural Principles – Dynamic Adaptation, Cross-Layer Optimization, AgentBased Capabilities, Soft-State – New ways of thinking of distributed network-aware service architectures, driving towards NINJA • Importance of Testbeds to Drive Research – Unanticipated challenges and research opportunities in asymmetric access, active services architecture, scalable service deployment – Develop prototypes through several generations • Fragility of Student-Developed Infrastructure – Maintaining the code base when the hardware base changes with each new PC order – Is NT development unavoidable? 58 Conclusions • A small team of outstanding graduate students can accomplish amazing things in a short period of time • Let’s celebrate their success! 59