1 / 13

QoS Enhanced Middleware

QoS Enhanced Middleware. Jürgen Dittrich & Marcin Solarski (GMD Fokus). Middleware: Shields Developer from underlying Technology changes Clear description of Customer/Provider interfaces Functional interfaces typically described in OMG/IDL OMG CORBA focused on QoS bindings with IIOP/TCP

amora
Télécharger la présentation

QoS Enhanced Middleware

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. QoS Enhanced Middleware Jürgen Dittrich & Marcin Solarski (GMD Fokus)

  2. Middleware: • Shields Developer from underlying Technology changes • Clear description of Customer/Provider interfaces • Functional interfaces typically described in OMG/IDL • OMG CORBA focused on QoS bindings with IIOP/TCP • Open issue: Expressing QoS req’s & Map them on bindings • Extended Object Bindings (UDP, LRMP, RSVP) • Extended Object Implementations (Replications)? • Example Application: Jonathan based Online Auction • Expressing QoS Req’s: Quality Modeling Language (QML, HP Labs) • Mapping QML on Extended DOT (bindings&impl’s)

  3. Quality Modeling Language (QML, HP labs) • Specification of QoS requirements • Related to ISO concepts • Declarative language related/similar to OMG UML/IDL • Language constructs: • contract type (QoS category: performance, availability, ..) • type AuctionPerformance = contract • { • response_time : decreasing numeric msec; • failure_rate : decreasing numeric no/sec; • }; • contracts (independent from functional IDL interface) • profile (associates contracts and IDL interfaces)

  4. Quality Modeling Language (QML, HP labs) • Relationships of QML constructs

  5. Quality Modeling Language (QML, HP labs) • QML in Middleware

  6. Modular ORB and QoS Agents • QoS Agent maps & negotiates QoS requirements/offers • Part of object binding Provided QoS Requested QoS server client QoS mapping Binding (inter-object protocol, ...) QoS on creation bindingfactory

  7. Dutch Flower Auction in Aalsmeer/NL

  8. Computational View of Online Dutch Auction Dealer 2. bid(); Multicast binding Mediator Dealer 1. offer(); Dealer

  9. Example Application:Jonathan based Online Auction

  10. Some QoS Requirements of the Dutch auction system • Reliability • Reliable communication channels • Scalability • Hunderts of dealers • All dealers need the same QoS of the communication. • Availability • The mediator has to be functional during the whole auction. • Mediator crashes have to be tolerated

  11. Solution mechanisms • Reliability • light-weight reliable multicast channel (LRMP) • reliable pt-to-pt channel for back channel (IIOP) • Scalability • Level-based architecture for mediators • Availability • Mediator Replication

  12. Choice of the QoS attribute on the example of the replication mechanism • Replication scheme • Active • high availability • replica implementation determinism • Passive • lower availability • No determinism requirement • Hybrids • semi-active, etc. • How to automate the choice the right mech? • QoS mapping

  13. Conclusions • Specification of QoS in QML • QoS Mapping/Translation & Tuning w/ QoS Agents • QoS Enhanced bindings build upon Modular ORB/Middlew. • QoS Enhanced bindings encompass communication and execution aspects • Online Auction for Evaluation of QoS Enhanced Middleware

More Related