Technologies for PubSub Application Format (PSAF) Leonardo Chiariglione CEDEO.net Kenichi Nakamura (Panasonic) Giuseppe Tropea (CNIT) Valencia, ES, 2014/04/01 1

Publish/Subscribe (PubSub) An established communication paradigm where communication is Not directly between Sender and Receiver but Mediated by a service between Sender and Receiver How it works Senders (called Publishers) post information on their information to a service Receivers (called Subscribers) declare their interest in a certain type of information to the same service The match service detects Pub/Sub matches and notifies accordingly 2

PubSub actors and workflow Creator stores content Publisher publishes information on content Subscriber subscribes to a type of content Match Service Matches subscription with publication Issues appropriate notification(s) Consumer plays content referenced in notification 3

Information exchange in PubSub StepInformation type Creator stores resourceResource ID Creator stores info on resourceResource format (RI) Publisher publishes info on resource Publication format (PI) Subscriber subscribes to resources of his interest Subscription format (SI) Service matches sub with pubsNo requirement Service issues notification(s)Notification format (NI) Subscriber opens notification, requests/plays resource No requirement 4

Information Centric Networking (ICN) 5 In ICN, entities are individual, identifiable (named) content elements, instead of unidentifiable data containers (i.e., IP packets) Give me today’s issue of Time Magazine Connect me with host Current Address Centric Networking Future Information Centric Networking PubSub is well suited for ICN

PubSub users shall be able to/1 1. Define lists of users to be/not to be notified of an event Enumerations Groups of users Users satisfying certain conditions 2. Reference the Resource via a standard information package containing Descriptions of Resource Rights and conditions for use of Resource List of users to be notified that specific use of a Resource has been made 6

PubSub users shall be able to/2 3. Select Match Service Provider(s) 4. Prescribe to Match Service Provider ;ist of Pub-Sub users to be considered in computing matches, specifically defined as Subscriptions to be/not to be considered as candidates for matches with publications Publishers to be/not to be considered as candidates for matches with subscribers Users to be/not to be notified of an event in the event of a match 7

PubSub users shall be able to/3 5. Define additional conditions to be added to Publications and Subscriptions such as Validity of Publication/Subscription (i.e. the period of time defined by a start and end time the Match Service Provider shall notify matches) 6. Update their Publications/Subscriptions 8

Elements of Resource Information 9 Resource Name the RI refers to Metadata for the purpose of Resource use ID of user who creates RI Rights to use Resource that include  Principal ID(s)  Resource Locator/Address/Name the Rights refer to  Rights to use  Conditions to use ID of users to be notified that Resource has been used ID of Resource Information Signature of user who creates RI

Elements of Publication Information 10 ID of RI this PI refers to Metadata for the purpose of Resource publication ID of Publisher Rights to match Publication Metadata including  Match Service ID(s)  ID of this PI  Right to match, for how long  Subject to condition that Subscriptions come/do not come from specific Users ID of users who shall be notified of a match ID of users who shall not be notified of a match found ID of PI Publisher’s Signature

Elements of Subscription Information 11 Query ID of Subscriber Rights to match Query that includes  Match Service ID(s)  ID of this SI  Right to match, for how long  Subject to condition that Publications come/do not come from specific User ID(s) ID of users who shall be notified of a match ID of users who shall not be notified of a match ID of SI Subscriber’s Signature

Elements of Notification Information 12 ID of RI ID of PI ID of SI ID of Notifier ID of NI Match Service Provider’s Signature

Match Service Peer2 Peer1 RI PI SI PI NI RI Content Centric Network RI MATCH Request RI Store RI Publish PI Subscribe SI NI Publish/Subscribe in ICN

Technologies for PSAF MPEG technologies to specify the PSAF Digital Item Digital Item Identifier Simple Metadata Profile MPEG Query Format Rights Expression Language Event Reporting Outside MPEG to specify the PSAF W3C Signature Recommendation. 2012/09/13 14 A gateway to new opportunities for digital content

Design of RI, PI, SI, NI/1 INFORMATION OBJECT HEADER PAYLOAD RIGHTS NOTIFICATION HEADER INFORMATION OBJECT ID SIGNATURE of INFORMATION OBJECT’s creator 2012/09/13 15 A gateway to new opportunities for digital content

Design of RI, PI, SI, NI/2 PAYLOAD TYPE of payload (R, P, S, N) USER ID of INFORMATION OBJECT’s creator METADATA {optional, for instance in case of NI} [ RESOURCE METADATA ] or [ PUB METADATA ] or [ SUB METADATA ] RESOURCE METADATA [ KEYWORDS ] or [ FIELD-VALUE ] or [ STRUCTURED DATA ] PUB METADATA [ KEYWORDS ] or [ FIELD-VALUE ] or [ STRUCTURED DATA ] SUB METADATA QUERY List of IDs of INFORMATION OBJECTs the PAYLOAD refers to {optional, e.g. in case of SI} 16

Design of RI, PI, SI, NI/3 RIGHT PRINCIPALs List of USER/SERVICE IDENTIFIERS VERBs ID of INFORMATION OBJECT the RIGHT refers to CONDITIONs [ List of USERs who must be involved in the RIGHT ] or [ other REL conditions ] NOTIFICATION RECIPIENTs to notify List of USER IDs to notify List of USER IDs not to notify 17

Discussion – PAYLOAD/1 KEYWORD and FIELD-VALUE to cover most PubSub Applications’ needs for STRUCTURED DATA element imported by the didl- msx schema to define any kind of XML based metadata (including RDF/XML) - when metadata in the form of field/value is not sufficient QUERY element imported from the MPEG Query Format schema (e.g. of InputQueryType). The MPQF schema can contain any kind of queries, as it can flexibility define complex disjunctive/conjunctive queries of any type e.g. SPARQL, XQuery, or field/value. 18

Discussion – PAYLOAD/2 Identifier of user/peer that created the Information object – needed to serve as conditions (in the RIGHT block of matching objects) to filter the match based on information issuer. Identifiers the payload refers to – a vital information to be reported back to users: for instance In NI the triple {ID of PI, ID of SI, ID of RI} is reported back to a subscriber to signal that the specific SI issued by the subscriber matches a specific PI and the relevant resource can be located through the given RI 2012/09/13 19 A gateway to new opportunities for digital content

Discussion – RIGHT/1 Requires a verb to indicate the right to perform MATCH of a pub with a sub and vice-versa. Current REL specification does not appear to include such a verb. Need to specify conditions, to restrict MATCH to Information objects coming from selected issuers or to notify only of matches that satisfy the given conditions. We want to have the right to match a pub with a sub to be subject to the fact that a “third party shares in the execution of the right”, in addition to the right’s principal 2012/09/13 20 A gateway to new opportunities for digital content

Discussion – RIGHT/2 A new verb NOTIFY is a possible alternative, i.e. he right to create a list of users/peers to be notified depending on the result of satisfying the conditions expressed in Publications Users to be/not to be notified Subscriptions that are eligible for matches with Publications Subscriptions Users to be/not to be notified Publications that are eligible for matches with Subscriptions 2012/09/13 21 A gateway to new opportunities for digital content

Discussion – RIGHT/3 An alternative is the use of CEL. In REL “Pub-Sub user gives MSP the right to match” and MSP has the duty to notify In CEL more sophisticated Pub-Sub user vs Match Service Provider relationships can be encoded Publisher will pay 20 € if MSP notifies 1000 (Mil) Subscribers as profiled in Publication, satisfying Subscribers’ conditions. The Cost Per Mil (CPM) notifications could depend on how finely the Publication profiles Subscribers. With User Description Publishers (Subscribers) can make fine specification of target Subscribers (Publisers) because Pub-Sub users share the semantics of user descriptors. 22

Discussion - NOTIFICATION Whenever a match occurs between a specific PI and SI, the notification lists of PI and SI are crosschecked to preserve the request made by Pub-Sub users for dissemination of notifications If user A is on the black list of the SI (i.e. SI’s creator B didn’t want user A to be notified whenever B’s SI gets matched), but also on the white list of the PI, user A will not be notified. The white list may include the creator of the Information object but, if that user appears on the black list of the matching Information, the original creator is not notified. 23

Mapping to existing technologies 2012/09/13 24 A gateway to new opportunities for digital content PSAF Element Existing Technology Notes HEADERDI and DII (and W3C Signature) Fully covered PAYLOADDI, DII, MPQF, Simple Metadata Profile Application specific and main subject of this specification RIGHTREL, ERWell covered with exceptions relative to new verb and conditions

Schema of PSAF Payload/1 25

Schema of PSAF Payload/2 26

Schema of PSAF Payload/3 27

Conclusions This document proposes Multimedia application requirements in PubSub messaging that take into account controlled distribution of information Four payload formats A set of (MPEG) technologies that can be used to specify the formats There are some alternatives that may need further investigations but there is enough material to start drafting the PSAF standard 28