Content for  TS 26.150  Word version:  18.0.0

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0  Introductionp. 5

Syndicated feeds, using technologies such as Atom and Really Simple Syndication (RSS), are widely used on today's Internet for various scheduled pull applications such as podcast. There are a number of non-compatible proprietary extensions and a number of different RSS variants that may need to be installed and updated.
OMA DCD has defined Channel and Content Metadata and related mechanisms for content delivery (including RSS and ATOM feeds) using Content Metadata XML extensions independently of any bearers. As a consequence there are no specific optimizations for 3GPP services/bearers. OMA DCD specification allows embedding of OMA DCD XML namespace elements into RSS and Atom document (RSS and Atom feed "content packaging formats"). The OMA DCD Channel and Content Metadata are intended to offer different content delivery alternatives to receivers.
The Syndicated Feed Reception (SFR) specification intents to define the optimized reception for any existing syndicated feeds using 3GPP specific bearers. SFR re-uses OMA DCD procedures and metadata for client server transactions.

1  Scopep. 6

The present document defines a set of media codecs, formats and transport/application protocols to enable syndicated feed reception within the 3GPP system.
The present document includes information applicable to network operators, service providers and manufacturers.

2  Referencesp. 6

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
  • References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific.
  • For a specific reference, subsequent revisions do not apply.
  • For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
TR 21.905: "Vocabulary for 3GPP Specifications".
TS 41.001: "GSM Specification set".
→ to date, withdrawn by 3GPP
RSS Advisory Board: "Really Simple Syndication 2.0".
RFC 4287:  "The Atom Syndication Format".
Open Mobile Alliance - "OMA Dynamic Content Delivery V1.0": June 2009.
TS 26.234: "Transparent end-to-end Packet-switched Streaming Service (PSS); Protocols and codecs".
TS 26.244: "Transparent end-to-end packet switched streaming service (PSS); 3GPP file format (3GP)".
TS 26.346: "Multimedia Broadcast/Multicast Service (MBMS); Protocols and codecs".
Open Mobile Alliance - "OMA Push V2.2": June 2009.
RFC 4281:  "The Codecs Parameter for Bucket Media Types", Gellens R., Singer D. and Frojdh P., November 2005.
Open Mobile Alliance - "User Agent Profile Version 2.0": February 2006.

3  Definitions and abbreviationsp. 6

3.1  Definitionsp. 6

For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.
Syndicated Feed:
A document, formatted according to RSS, ATOM, DCD or other syndicated feed formats, which is frequently updated with new content updates.
Syndicated Feed Reader:
The client, which receives and processes one or more syndicated feed formats.
Syndicated feed URI:
A Uniform Resource Identifier, pointing to the document, which is formatted according to RSS, ATOM or other syndicated feed formats.
Syndicated Feed Provider:
A content provider, which uses HTTP servers to provide syndicated feeds for download.
SFR enabled Feed Reader:
A feed reader, which is able to use optimized receptions and/or optimized enclosure handling as defined in the specification.
SFR Server:
Server, which offers methods for optimized reception of syndicated feeds for SFR enabled Feed Readers.

3.2  Abbreviationsp. 7

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905.
General Packet Radio Service
Internet Protocol
Dynamic Content Delivery
Multimedia Broadcast/Multicast Service
Packet Switch Streaming
Really Simple Syndication
Syndicated Feed Reception
User Equipment
Uniform Resource Identifier
Uniform Resource Locator
eXtensible Markup Language

4  System descriptionp. 7

4.1  Functional overviewp. 7

The following diagram (see Figure 1) illustrates the overall system for syndicated feed reception (SFR). The system is subdivided into an SFR enabled Feed Reader, a SFR server and Syndicated Feed Provider.
SFR enabled Feed Readers are clients, which provide all the functionality to parse, process and (opt.) present syndicated feeds. The SFR enabled Feed Reader can interact with any legacy syndicated feed server (e.g. RSS or Atom) using HTTP. Additionally, those clients are also able to optimize the syndicated feed reception and/or optimize the handling of enclosures as defined in this specification. SFR enabled Feed Readers may support one or more syndicated feed formats such as RSS or Atom. From an implementation/deployment perspective, the SFR enabled Feed Reader can be shared by multiple ATOM/RSS-based applications or could be incorporated as a part of such an application.
SFR enabled Feed Readers, which include "optimized reception" of feed updates and/or enclosures support interactions with SFR servers.
SFR servers offer the SFR enabled Feed Reader with functions to optimize the reception of feed updates, attached media and enclosures. SFR servers interact with one or more syndicated feed servers. The interaction protocols and procedures of SFR server with Syndicated feed servers are out of scope of this specification. The SFR server is a profiled OMA DCD server dedicated to optimize syndicated feed delivery.
Syndicated feed providers are legacy functions, which use HTTP to offer their syndicated feeds.
Copy of original 3GPP image for 3GPP TS 26.150, Fig. 1: Overall SFR System
Figure 1: Overall SFR System
(⇒ copy of original 3GPP image)
The SFR enabled Feed Reader interacts with the SFR server in order to get an optimized reception of syndicated feeds using the "Admin" reference point. The SFR server provides the SFR enabled Feed Reader with feed content using OMA Push or MBMS download delivery using the "Push" reference point. The "Pull" reference point is used, when the SFR enabled Feed Reader pull content from the SFR server. The "Admin", "Push" and "Pull" reference points are realized using a subset of the OMA DCD-3, DCD-2 and DCD-1 reference points [5].
The "Admin" transactions between SFR enabled Feed Reader and SFR server re-use a subset of the OMA DCD-3 transactions. The "Push" procedures between SFR server and SFR enabled Feed Reader re-use the OMA DCD-2 transactions (see clause 5.6) and extend them to cover MBMS delivery via direct binding. The "Pull" Interface to the SFR Server corresponds to "DCD-1". The "Pull" procedures between SFR server and SFR enabled Feed Reader re-use a subset of OMA DCD-1 transactions (See clause 5.6). The SFR enabled Feed Reader implements a profile of the DCD client and supports some of the DCD Enabled Client Application (DECA) functionalities.
The "Poll" interface to the syndicated feed provider (dashed line) corresponds to the stateless pull of legacy syndicated feed readers using HTTP. The "Poll" interface is not in scope of this specification.
The profiling of DCD [5] is defined in clause 5.7.

4.2  Operations overviewp. 8

Syndicated Feed Reader, which want to use "optimized reception" as defined in this specification must first activate and register with the SFR server to establish a session and then initiate the optimized reception of desired Syndicated Feeds (i.e. also called channels).
The SFR server provides the SFR enabled Feed Reader with a session-id as value of the Session-ID field in the activation response message that corresponds toa successful activation. This session-id is used during all later transactions. One or more syndicated feed reception channels may be added to or removed from the session at any point in time.
The SFR enabled Feed Reader use the Syndicated Feed URI (content address) of the syndicated feed to initiate the optimized reception. The SFR Server shall use the content address of the syndicated feed as value for the Channel-ID field. The Channel-ID value is used to identify specific syndicated feeds during later transactions. The Channel-ID value is present at any syndicated feed related transaction.
The session is persistent, even if the UE is switched-off. However, all or some channels can be suspended. The UE may suspend some or all syndicated feeds when roaming in foreign networks by sending a channel suspend request to the SFR server. The SFR enabled Feed Reader may also indicate as part of the channel subscription procedure that while roaming, content delivery shall automatically be suspended. In that case and upon detection that the UE is roaming, the SFR server shall suspend the delivery.
Each transaction on the "Admin", "Push" and "Pull" reference point is uniquely identified by a transaction-identifier, which is provided with the value of the Message-ID field. The value of the Message-ID field is composed of a unique transaction-id identifier followed by two numeric characters for message index within the transaction. The transaction identifier is the same for all related messages of a transaction within a session.
The SFR enabled Feed Reader can find e.g. the response to a certain request message based on the transaction-identifier. All messages belonging to the same transaction shall use the same transaction identifier value in the Message-ID field.
Example of message-id:
Transaction id= 01178AC32
Message id = 01178AC3200 for the first message, and message id = 01178AC3201 for the second message.

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