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“Design Review”

“Design Review”. Randy H. Katz, Anthony Joseph, Ion Stoica Computer Science Division Electrical Engineering and Computer Science Department University of California, Berkeley Berkeley, CA 94720-1776. The “Sahara” Project. S ervice A rchitecture for H eterogeneous A ccess,

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“Design Review”

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  1. “Design Review” Randy H. Katz, Anthony Joseph, Ion Stoica Computer Science Division Electrical Engineering and Computer Science Department University of California, Berkeley Berkeley, CA 94720-1776

  2. The “Sahara” Project • Service • Architecture for • Heterogeneous • Access, • Resources, and • Applications

  3. Sahara Research Themes • New mechanisms, techniques for end-to-end services w/ desirable, predictable, enforceable properties spanning potentially distrusting service providers • Tech architecture for service composition & inter-operation across separate admin domains, supporting peering & brokering, and diverse business, value-exchange, access-control models • Functional elements • Service discovery • Service-level agreements • Service composition under constraints • Redirection to a service instance • Performance measurement infrastructure • Constraints based on performance, access control, accounting/billing/settlements • Service modeling and verification

  4. Applications (Portals, E-Commerce, E-Tainment, Media) Appl Infrastructure Services (Distribution, Caching, Searching, Hosting) AIP ISV Application-specific Servers (Streaming Media, Transformation) ASP Internet Data Centers Application-specific Overlay Networks (Multicast Tunnels, Mgmt Svrcs) ISP CLEC Internetworking (Connectivity) Global Packet Network Horizontal Service Model Applications-enabling Services Processing/Storage Location & Placement Reachability & Topology

  5. Cable Modem Premises- based AccessNetworks LAN Transit Net LAN LAN Private Peering Premises- based Core Networks Transit Net WLAN WLAN Internet Datacenter NAP Analog WLAN Transit Net Public Peering DSLAM Operator- based RAS Regional Wireline Regional Cell H.323 Data Cell Data H.323 Cell PSTN Voice Voice Connectivity and Processing

  6. Goals of the Design Review • Originally • Present technical architecture for comment/review • But, • Not ready to do so! • Too early in our thinking for comprehensive architecture • So, • Snapshot of our current thoughts • Scenarios of service provision • Dialog with industry colleagues on essential components of architecture and their interactions

  7. Research Questions:Service Design • For a given community of users and a given set of performance, availability, and administrative constraints, • Service Provisioning Problem: How many instances of a service are needed? • Service Placement Problem: Where should these services be placed? • Adaptive Services: How do these deployments change with evolution of the user community and variations in usage demand?

  8. Research Questions:Composition Over Providers • Cooperative service placement • Consider placement from perspective of entire community of service providers • How to achieve best possible placement across whole community? • How do service providers make known their services for possible peering/composition with other providers (mechanisms of service advertisement/service level agreement)? • How are these offered services verified (service agreement verification)? Which service provider is responsible?

  9. Research Questions: Spanning Service Providers • Brokered service placement • Form own service composition by picking & choosing among service instances discovered from underlying service providers • How is service quality determined by 3rd-party broker (performance verification)? • How is service composition correctness determined by the 3rd-party broker (protocol verification)?

  10. Research Questions • Service Identification/Choice Problem • Given an application (e.g., content distribution), which is the best service (e.g., cache/storage resources, transport/interconnection connectivity and bandwidth for performance-constrained delivery) for supporting it? • Service Selection Problem • Given provisioning & placement of services within admin domain, which is “best” service instance? • Considering load, distance/latency between clients of the service and where the service is placed, subscription/billing relationships, loyalty/affinity relationships, preferences, etc.

  11. Service Examples • Connectivity/Reachability • Basic Internet routing between ASs • More sophisticated multicast distribution formation • Performance constrained connectivity/latency and bandwidth guarantees (e.g., Clearinghouse/Soft QoS) • Performance monitoring services (distance/latency mapping, load collection/balancing across service instances) • Content distribution services: cache/storage resources, distribution/transport resources

  12. What is a Service? • Content transformation services (format translators) • Gateway selection under load and performance constraints • Resource allocation services (e.g., auctions for bandwidth, processing, storage) • Mobility services (e.g., device ensembles) • Who is allowed to invoke a service: Authentication, Accounting, Access Control • Payment for services: billing, financial clearinghouses • Interworking services across administrative domains/different technologies

  13. Some Starting SAHARA Assumptions • Dynamic confederations to better share resources & deploy access/achieve regional coverage more rapidly • Scarce resources efficiently allocated using dynamic “market-driven” mechanisms • Trusted third partners manage resource marketplace in a fair, unbiased, audited and verifiable basis • Vertical stovepipe replaced by horizontally organized “multi-providers,” open to increased competition and more efficient allocation of resources • Sanity Check?

  14. Implications for Architectural Elements • “Open” service/resource allocation model • Independent service creation, establishment, placement, in overlapping domains  • Resources, capabilities, status described/exchanged amongst confederates, via enhanced capability negotiation • Allocation based on economic methods, such as congestion pricing, dynamic marketplaces/auctions • Trust management among participants, based on trusted third party monitors

  15. Implications for Architectural Elements • Forming dynamic confederations • Discovering potential confederates • Establishing trust relationships • Managing transitive trust relationships & levels of transparency • Not all confederates need be competitors--heterogeneous, collocated access networks to better support applications

  16. Architectural Elements • Alternative View: Service Brokering • Dynamically construct overlays on component services provided by underlying service providers • E.g., overlay network segments with desirable performance attributes • E.g., construct end-to-end multicast trees from subtrees in different service provider clouds • Redirect to alternative service instances • E.g., choose instance based on distance, network load, server load, trust relationships, resilience to network failure, …

  17. Separate apps from exec environ service-specific from control Generic (Common) Objects + Service-Specific Objects Session: duration-based context for processes provisioning a service Access session (authen-tication, service selection) Service session User service session (user state, resources) Provider service session (service logic) Comm session: abstract view of net connections TINA Reference Model Service Generic Mgmt & Control Applications Objects Sessions Trans- port Distributed ProcessingEnvironment Network Environment

  18. Business Model Roles/entities & their relationships while participating in service provisioning E.g., consumer, retailer, broker, 3rd party provider, content provider, connectivity provider Information Model Information-bearing entities E.g., user and service profiles Computational Model Computational objects & their relationships TINA Reference Model Service Generic Mgmt & Control B u s i n e s s M o d e l I n f o r m a t i o n M o d e l C o m p u t a t i o n a l M o d e l Applications Objects Sessions Trans- port Distributed ProcessingEnvironment Network Environment

  19. Composed Services Under Investigation • Overlay routing “service”: connectivity and reachability (BGP++: Sharad, Lakshmi, Morley) • Multicast service: distribution tree formation across administrative domains (Mukund) • Soft QoS Service: performance constrained connectivity/latency and bandwidth guarantees (Clearinghouse: Chen-nee, Lakshmi) • Performance monitoring service: distance/latency mapping, load collection/balancing across service instances (Yan) • Content distribution services: cache/storage resources, distribution/transport resources (Yan, Morley)

  20. Infrastructure Services Highly available/fast fall-over services in wide-area (Bhaskar);Fall-back path bandwidth provisioning (Weidong); Service instance selection, load-balanced resource sharing; Resource allocation/auctions and class-of-service pricing for bandwidth, processing, storage (Weidong & Matt); Mobility and cooperation across access networks/device ensembles (Machi) Interdomain Authentication & Access Control (Suzuki) Applications Content transformation/format translators; Universal In-Box (Bhaskar) H.323 Gateway selection under load & performance constraints (Matt) VoIP and bandwidth congestion pricing (Jimmy) Smart Spaces/PAN? Composed Services Under Investigation

  21. Network Environment Explicitly distinguish between multiple Access Networks and Core Networks “Gateway Provider” (GP) Points of Presence between different kinds of networks “Path” Provider (PP) Autonomous systems (AS) determine service domains for purposes of reachability Peering between administrative domains managed via BGP Point-to-point (and multipoint) latency, availability SLAs within a single administrative domain “Datacenter” Provider (DCP) Distributed computing resources (processing, storage) embedded within network topology Load/latency/availability SLAs within single datacenter location SAHARA Architecture Service Generic Mgmt & Control Applications Objects Sessions Trans- port Distributed ProcessingEnvironment Performance Verification SLAs Network Environment

  22. Distributed Processing:Service Placement Place objects (operators + data) at DCs, connected by paths Multiple object and path instances for load balancing, availability, scale Brokers Given performance & other constraints: Path brokering: create “overlay network” among processing sites,link by link DC brokering: given distribution of clients, select processing sites for operators Confederations Visibility of (alternative) paths, DCs among associated providers Peer-to-peer reassignment of objects to DCs and paths SAHARA Architecture Service Generic Mgmt & Control Applications Objects Sessions Trans- port Distributed ProcessingEnvironment Network Environment

  23. Distributed Processing:Service Building Services Authorization, Authentication, Accounting Interworking services spanning administrative domains Service Selection and Naming Service Choosing a “best” service Finding “nearest” service instance Service Redirection Service Load balancing among service instances Selecting the best among services with common affinity Mobility support Resource Allocation Service Auction-based allocation Performance Measurement Service Network distance measurements Latency measurements for operator invocation over network SAHARA Architecture Service Generic Mgmt & Control Applications Objects Sessions Trans- port Distributed ProcessingEnvironment Network Environment

  24. Applications Unified messaging services (Universal In-box) Content xform proxies Latency, availability, scalability Content-distribution services Cache placement & replenishment algorithms Adaptive to client community evolution IP Telephony H.323 gateway selection/load balancing Balance between packet (IP) and circuit-switched (PSTN) path Device Ensembles/Virtual Devices Inter-network stream synchronization Virtual device proxy placement Virtual Home Environment SAHARA Architecture Service Generic Mgmt & Control Applications Objects Sessions Trans- port Distributed ProcessingEnvironment Network Environment

  25. SAHARA and TINA • Key Differences • Extreme heterogeneity of spanned networks and resources • Greater awareness and management of underlying network topology/administrative scopes and affect on services • Focus on • Cooperative vs. competitive service composition • Resource management via placement, allocation, redirection to services and resources • Borrow good parts of TINA • Applications/Distributed Processing/Network Environment • Business models/Information Model/Computation Model • Understand why TINA failed • Avoid full-blown complexity of TINA

  26. Application: Content Delivery Clients: Subscribers, Publishers Services Distribution network Content caches (service instances) Place caches at selected DCs (service placement) Redirect client to “best” cache instance (service redirection) Based on proximity, load, content Service Composition Broker multi-point distribution paths between publishers and caches Add/delete cache instances as client community grows/shrinks Brokering at content level among competing CDNs Example: Content Distribution Service Generic Mgmt & Control Applications Objects Sessions Trans- port Distributed ProcessingEnvironment Network Environment

  27. Composed Services Application plane Peering Relations Overlay Network Logical platform Service Clusters Gateways Hardware platform SAHARA Architectural Model

  28. Composed Services Application plane Peering Relations Overlay Network Logical platform Service Clusters Gateways Hardware platform SAHARA Architectural Model Service Path Creation Service Selection Service Placement Service Location Perf Measurement

  29. Composed Services Application plane Peering Relations Overlay Network Logical platform Service Clusters Gateways Hardware platform SAHARA Architectural Model Load Balancing Service Selection Service Placement Service Redirection Perf Measurement

  30. Composed Services Application plane Peering Relations Overlay Network Logical platform Service Clusters Gateways Hardware platform SAHARA Architectural Model Service Brokering Path Determination Perf Measurement Verification

  31. Composed Services Application plane Peering Relations Overlay Network Logical platform Service Clusters Gateways Hardware platform SAHARA Architectural Model Service Confederation Service Discovery SLA Negotiation Perf Measurement SLA Verification Authentication & Authorization Interworking Mobility Interworking

  32. Composed Services Application plane Peering Relations Overlay Network Logical platform Service Clusters Gateways Hardware platform SAHARA Architectural Model High Availability Services Service Failure Detection Service Recovery Path re-composition

  33. Composed Services Application plane Peering Relations Overlay Network Logical platform Service Clusters Gateways Hardware platform SAHARA Architectural Model High Availability Services Service Location Path Orthogonality Determination

  34. Composed Services Application plane Peering Relations Overlay Network Logical platform Service Clusters Gateways Hardware platform SAHARA Architectural Model Universal In-Box Translator Provisioning and Placement Path Determination

  35. Composed Services Application plane Peering Relations Overlay Network Logical platform Service Clusters Gateways Hardware platform SAHARA Architectural Model Content Distribution Cache Provisioning and Placement Distribution Tree Formation

  36. Composed Services Application plane Peering Relations Overlay Network Logical platform Service Clusters Gateways Hardware platform SAHARA Architectural Model Voice over IP Gateway Provisioning and Placement Packet-to-CircuitTermination Selection

  37. Summary and Status • Evolve (mobile) Internet architecture to better support multiple service provider model • Dynamic environment, location-based implies larger numbers of service providers & service instances • Refine and build SAHARA Architecture • Specification driven by selected applications and underlying wide-area services • Composition across confederated vs. independent service providers: peer-to-peer vs. brokering

  38. Discussion

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