© 2006 Open Grid Forum INFOD Extended Specifications OGF21, Seattle, WA, USA...

© 2006 Open Grid Forum

INFOD Extended SpecificationsOGF21, Seattle, WA, USA

[email protected]

2© 2006 Open Grid Forum

Overview

• Status • Steve Fisher (RAL)

• INFOD prototype• Raghul Gunasekaran (UTK)

• Extended specifications• Objectives• Some requirements • Extensions – some ideas


Before we Start

• The INFOD group intends to add extension covering new use cases and potentially simplifying use cases that are already covered

• This presentation described a set of potential enhancements• There is no consensus yet about the extensions –

a consensus is about 6 to 12 months away

• The INFOD group is looking for additional use cases and suggestions


Objective

• Improve subscriptions• We need even more functionality and flexibility

• Support relations between publishers and consumers respectively • Allow division of labor between publishers and

consumers respectively• OR – add the notion of a broker

• Clean up interface• REPLACE operation

• Add as few elements as possible


Some Use Cases

• Inform local fire department if average temperature within 20 miles is 2 degrees higher than forecasted and condition ‘red’ exists

• Provide weather information to Plume Prediction Services for all chemical sensors located within an area


Requirements - Other

• Support lightweight publishers (producers)• Allow sensors to outsource publication of

information

• Support lightweight consumers • Allow actuators to outsource receiving

information


The INFOD Model

Publisher Consumer

Subscriber

Publisher/Entry

SubscriberEntry

SubscriptionConsumer

Entry

Data Vocabulary Property Vocabulary

Data SourceEntry

Property VocabularyInstance

Creation of resourceNotification (by INFOD registry)

Reference (EPR)Notification (by Publishers)

Entry Resource – not an entry


The Extended INFOD Model

Publisher Consumer

Subscriber

PublisherEntry

SubscriberEntry

SubscriptionConsumer

Entry


Data SourceEntry


Producer/Publisher/Disseminator

Producer/Publisher/Disseminator Entry

POBox/Consumer

POBox/ConsumerEntry

Creation of resourceNotification (by INFOD registry)

Reference (EPR)Notification (by Publishers)



An Alternative – Broker

Publisher Consumer

PublisherEntry

SubscriberEntry

Subscription

ConsumerEntry


Data SourceEntry


Creation of resource

Notification (by INFOD registry)

References (one or more EPRs)

Notification (by Publishers/Brokers)


Broker

Subscriber

BrokerEntry


(Partial) List of Work Items

• Association between publishers • Association of data sources to multiple publishers

• Association between consumers• Delivery policies

• Improved subscriptions• ?? Brokers • Subscriptions to the INFOD registry• Distributed INFOD registries• Non WS-Notification data movement• Improved REPLACE Operation


Association Between Publishers

• Publisher should be able to cooperate with each other: • Simple publishers; e.g., sensors

• Focused on creation of data – conditional (data constraints) or unconditional

• Dissemination functions are out-sourced

• Full function publishers - disseminators• Process subscription and dissemination• Support of a wide range of operational characteristics including

auditing and tracking

• Method:• Associate publishers to other publishers• INFOD registry maintains and explores the relation


Association of Data Sources

• Data sources can be associated to multiple publishers• Directly through – secondary – publisher data

source association• Indirectly through association between publishers

• Publishers can support subscriptions referencing data sources from multiple publishers• Report the average temperature in Knoxville if it

deviates more than 2 degrees for the forecast – individual sensors are perceived as publishers


Association Between Consumers

• Consumers should be able to cooperate with each other: • Simple consumers; e.g., actuators

• Focused on reaction to – new – data• Dissemination functions are out-sourced

• Full function consumers - POBoxes• Receive and filter messages• Support of a wide range of operational characteristics

including auditing and tracking• Method:

• Associate consumers to other consumers• INFOD registry maintains and explores the relation


Message Delivery Policies

• Create subscription to related consumers – POBoxes to specify:• Filters• Forwarding – notification, full message• Time of delivery• EPR of delivery

• Use XQuery to look into history


Brokers??

• Many messaging or publish/subscribe system support the notion of a broker

• A broker is a resource acting as publisher, subscriber and consumer

• A broker consumes, selects, fuses, enriches and disseminates information

• Broker would keep the publisher and consumer model simple


Improved Subscriptions

• Through associations between publishers• Subscription can reference data sources from

multiple publishers

• Through extended subscription functionality• Additional procedure• Reference to registry data

• Notification with changes


Subscriptions to the INFOD Registry

• Use meta data subscriptions to get up-to-date information from INFOD registry• INFOD registry is publisher• Publisher, subscribers and consumers can

act as consumers• Notification about subscriptions will be

created• Structured as any other subscription


Distributed INFOD Registries

• Use subscription technology to share information

• There is no matching across registries


Non WS-Notification Dissemination

• Dissemination is currently done with WS-Notification

• Other Data Movement technologies are desirable to support a variety of operational characteristics

• Existing/proposed technologies will be considered; e.g., OGSA Data Architecture


REPLACE Operation

• Add REPLACE operations • Data Sources • Property Vocabulary Instances• No REPLACE operation for vocabularies

• Allow selective replacement of elements• Use XQuery DELETE to define entries to be

removed• Keep whatever is not deleted – important for

constraints with reference to resources marked with ‘DISABLE NEW’


If you want to contribute:

Join our Work session dedicated to the Extended Specifications on Thursday, October 18 @ 1:30 pm in Discovery A


Full Copyright Notice

Copyright (C) Open Grid Forum (2006). All Rights Reserved.

This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works.

The limited permissions granted above are perpetual and will not be revoked by the OGF or its successors or assignees.

© 2006 Open Grid Forum INFOD Extended Specifications OGF21, Seattle, WA, USA...

Documents

Transcript of © 2006 Open Grid Forum INFOD Extended Specifications OGF21, Seattle, WA, USA...