A qos policy modeling language for publish subscribe middleware platforms
This presentation is the property of its rightful owner.
Sponsored Links
1 / 10

A QoS Policy Modeling Language for Publish/Subscribe Middleware Platforms PowerPoint PPT Presentation


  • 46 Views
  • Uploaded on
  • Presentation posted in: General

A QoS Policy Modeling Language for Publish/Subscribe Middleware Platforms. Joe Hoffert, Doug Schmidt & Aniruddha Gokhale {jhoffert,schmidt,[email protected] www.dre.vanderbilt.edu ISIS, Dept. of EECS Vanderbilt University Nashville, Tennessee June 21, 2007

Download Presentation

A QoS Policy Modeling Language for Publish/Subscribe Middleware Platforms

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


A qos policy modeling language for publish subscribe middleware platforms

A QoS Policy Modeling Language for Publish/Subscribe Middleware Platforms

Joe Hoffert, Doug Schmidt & Aniruddha Gokhale

{jhoffert,schmidt,[email protected]

www.dre.vanderbilt.edu

ISIS, Dept. of EECS

Vanderbilt University

Nashville, Tennessee

June 21, 2007

DEBS 2007, Toronto, Canada

www.dre.vanderbilt.edu


Distributed real time embedded dre systems

Distributed Real-time & Embedded (DRE) Systems

  • Network-centric and large-scale “systems of systems”

    • e.g., industrial automation, emergency response

  • Different communication semantics

    • e.g., pub-sub

  • Satisfying tradeoffs between multiple (often conflicting) QoS demands

    • e.g., secure, real-time, reliable, etc.

  • Regulating & adapting to (dis)continuous changes in runtime environments

    • e.g., online prognostics, dependable upgrades, keep mission critical tasks operational, dynamic resource mgmt

DRE systems increasingly realized via system composition of services


Challenges in realizing dre systems

  • Variability in the solution space (systems integrator role)

  • Diversity in platforms, languages, protocols & tool environments

  • Enormous accidental & inherent complexities

  • Continuous evolution & change

Mapping problem artifacts to solution artifacts is hard

Challenges in Realizing DRE Systems

  • Variability in the problem space (domain expert role)

  • Functional diversity

  • Composition, deployment and configuration diversity

  • QoS requirements diversity


The omg data distribution service dds

Application

Application

read

write

write

Logical Data Store

Application

write

write

Application

read

read

Application

The OMG Data Distribution Service (DDS)

  • Provides flexibility, power and modular structure by decoupling:

    • Location – anonymous pub/sub

    • Redundancy – any number of readers & writers

    • Time – asynchronous, time-independent data distribution

    • Platform – similar to CORBA middleware

  • Architecturally Broken into:

  • Data Centric Publish/Subscribe (DCPS)

    • Lower layer APIs to exchange topic data based on QoS policies

  • Data Local Reconstruction Layer (DLRL)

    • Upper layer APIs that make topic data appear local


Qos policies supported by dds

QoS Policies Supported by DDS

  • DCPS entities (e.g., topics, data readers/writers) configurable via QoS policies

  • QoS tailored to data distribution in tactical information systems

  • Request/offered compatibility checked by DDS at Runtime

  • Consistency checked by DDS at Runtime

  • DEADLINE

    • Establishes contract regarding rate at which periodic data is refreshed

  • LATENCY_BUDGET

    • Establishes guidelines for acceptable end-to-end delays

  • TIME_BASED_FILTER

    • Mediates exchanges between slow consumers & fast producers

  • RESOURCE_LIMITS

    • Controls resources utilized by service

  • RELIABILITY (BEST_EFFORT, RELIABLE)

    • Enables use of real-time transports for data

  • HISTORY (KEEP_LAST, KEEP_ALL)

    • Controls which (of multiple) data values are delivered

  • DURABILITY (VOLATILE, TRANSIENT, PERSISTENT)

    • Determines if data outlives time when they are written

  • … and 15 more …


Qos policy configuration challenges

Reliable data transfer requested

Best effort data transfer offered

Data will not be transferred

X

Deadline’s period = 5 ms.

Time based filter’s minimum separation = 10 ms.

X

QoS policies will not be set

QoS Policy Configuration Challenges

  • QoS Policy Compatibility

    • QoS policies for the communicating entities must be compatible between what’s requested and offered

  • QoS Policy Consistency

    • QoS policies for any one entity must be consistent with each other

Need to flag errors earlier in the developmental lifecycle


Dds qos modeling language dqml 1 of 2

DDS QoS Modeling Language (DQML 1 of 2)

Focus on “correct by construction” – check for errors at design-time

  • Models relevant DDS entities

  • Models DDS QoS polices as first class entities

  • Models relationships between entities and QoS policies


Dds qos modeling language dqml 2 of 2

QoS Settings

QoS Settings

DataReader

DataWriter

DDS QoS Modeling Language (DQML 2 of 2)

  • Supports QoS compatibility and consistency constraint checking

  • Generates implementation artifacts (currently for DDS Benchmarking Environment (DBE))

DBE

Interpreter

DBE


Ongoing work dqml service orchestration

Ongoing Work: DQML + Service Orchestration

Work supported by DARPA PCES & ARMS Programs

  • CoSMIC tools e.g., PICML used to model application components, CQML for QoS

  • Captures the data model of the OMG D&C specification

  • Synthesis of static deployment plans for DRE systems

  • Capabilities being added for QoS provisioning (real-time, fault tolerance, security)

CoSMIC can be downloaded at www.dre.vanderbilt.edu/cosmic


Concluding remarks

QoS Settings

QoS Settings

Invoke the DBE

Interpreter

DBE

DataReader

DataWriter

Concluding Remarks

  • QoS configuration management is a significant challenge for pub-sub systems

  • Need design-time tools to automate the QoS configuration management

  • Need tools to assure “correct-by-construction” systems

  • Model-driven Engineering is a promising approach


  • Login