© 2006 open grid forum infod extended specifications ogf21, seattle, wa, usa...
TRANSCRIPT
2© 2006 Open Grid Forum
Overview
• Status • Steve Fisher (RAL)
• INFOD prototype• Raghul Gunasekaran (UTK)
• Extended specifications• Objectives• Some requirements • Extensions – some ideas
3© 2006 Open Grid Forum
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
4© 2006 Open Grid Forum
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
5© 2006 Open Grid Forum
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
6© 2006 Open Grid Forum
Requirements - Other
• Support lightweight publishers (producers)• Allow sensors to outsource publication of
information
• Support lightweight consumers • Allow actuators to outsource receiving
information
7© 2006 Open Grid Forum
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
8© 2006 Open Grid Forum
The Extended INFOD Model
Publisher Consumer
Subscriber
PublisherEntry
SubscriberEntry
SubscriptionConsumer
Entry
Data Vocabulary Property Vocabulary
Data SourceEntry
Property VocabularyInstance
Producer/Publisher/Disseminator
Producer/Publisher/Disseminator Entry
POBox/Consumer
POBox/ConsumerEntry
Creation of resourceNotification (by INFOD registry)
Reference (EPR)Notification (by Publishers)
Entry Resource – not an entry
9© 2006 Open Grid Forum
An Alternative – Broker
Publisher Consumer
PublisherEntry
SubscriberEntry
Subscription
ConsumerEntry
Data Vocabulary Property Vocabulary
Data SourceEntry
Property VocabularyInstance
Creation of resource
Notification (by INFOD registry)
References (one or more EPRs)
Notification (by Publishers/Brokers)
Entry Resource – not an entry
Broker
Subscriber
BrokerEntry
10© 2006 Open Grid Forum
(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
11© 2006 Open Grid Forum
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
12© 2006 Open Grid Forum
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
13© 2006 Open Grid Forum
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
14© 2006 Open Grid Forum
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
15© 2006 Open Grid Forum
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
16© 2006 Open Grid Forum
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
17© 2006 Open Grid Forum
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
18© 2006 Open Grid Forum
Distributed INFOD Registries
• Use subscription technology to share information
• There is no matching across registries
19© 2006 Open Grid Forum
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
20© 2006 Open Grid Forum
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’
21© 2006 Open Grid Forum
If you want to contribute:
Join our Work session dedicated to the Extended Specifications on Thursday, October 18 @ 1:30 pm in Discovery A
22© 2006 Open Grid Forum
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.