RFC 5328

A Uniform Resource Name (URN) Namespace for the Digital Video Broadcasting Project (DVB)

📅 published September 2008, from ietf

RFC 5328 💖 Title Block Tea ☕

okay so bestie, this is RFC 5328 and it's giving official DVB namespace glow-up 🎀 It's called "A Uniform Resource Name (URN) Namespace for the Digital Video Broadcasting Project (DVB)" and it came out in September 2008. The authors are A. Adolf from Micronas GmbH and P. MacAvock from the DVB Project. It's Informational, which means it shares info with the Internet community and does not specify an Internet standard 🦋 Nothing in the title block says it obsoletes or updates any other RFC, so it's a standalone moment ✨

Status of This Memo ✨

This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.

Abstract 🌸

This document describes a Uniform Resource Name (URN) namespace for the Digital Video Broadcasting Project (DVB) for naming persistent resources defined within DVB standards. Example resources include technical documents and specifications, eXtensible Markup Language (XML) Schemas, classification schemes, XML Document Type Definitions (DTDs), namespaces, style sheets, media assets, and other types of resources produced or managed by DVB.

Table of Contents 🗂️

   1. Introduction ....................................................2
   2. Specification Template ..........................................2
   3. Examples ........................................................4
   4. Namespace Considerations ........................................4
   5. Community Considerations ........................................7
   6. Security Considerations .........................................9
   7. IANA Considerations .............................................9
   8. References .....................................................10
      8.1. Normative References ......................................10
      8.2. Informative References ....................................11

1. Introduction 🎀

okay so DVB is an industry-led consortium of over 270 broadcasters, manufacturers, network operators, software developers, regulatory bodies and others in over 35 countries 🌍 Their whole mission is designing global standards for delivering digital television and data services. DVB services are available on every continent, with more than 100 million DVB receivers already deployed. That's a LOT of TVs, bestie 📺😭

DVB would like to assign unique, permanent, location-independent names based on URNs for some of the resources it produces or manages. These URNs will be built using the URN syntax defined in [RFC2141] 🧚

This namespace specification is meant to be a formal namespace, registered according to the procedures in [RFC3406] 💅

2. Specification Template 📋

This section has all the info needed to register a formal namespace under the registration procedure in [RFC3406]. The URNs follow the syntax in [RFC2141] ✨

Namespace ID

"dvb"

Registration Information

Version: 1
Date: 2007-02-28

Declared registrant of the namespace

Name:           Peter MacAvock
Title:          Executive Director, DVB Project Office
Affiliation:    DVB Digital Video Broadcasting
Address:        Ancienne Route 17a
                CH-1218 Geneva
                SWITZERLAND
Phone:          +41 22 717 2719
Email:          macavock@dvb.org

Declaration of structure

DVB URNs will have the following hierarchical structure, based on the organizational structure of the DVB standards 🌈

urn:dvb:<NSS>

where the syntax of <NSS> is specified in Section 2.2 of the URN Syntax requirements ([RFC2141]).

The individual URNs will be assigned by DVB through the process of developing DVB standards 🔥

Relevant ancillary documentation

None

Identifier uniqueness considerations

DVB will establish unique identifiers as appropriate.

Uniqueness is guaranteed, because DVB makes sure through its standardization process that an assigned string is never reassigned. Iconic behaviour 👑

Identifier persistence considerations

DVB is committed to maintaining the accessibility and persistence of all resources that the organization officially assigns URNs to 🫶

Process of identifier assignment

Assignment is limited to DVB and to the authorities that DVB specifically designates. DVB may designate portions of its namespace for assignment by other parties under its regime 🦋

Process of identifier resolution

DVB will develop and maintain "URN catalogues" that map all assigned URNs to Uniform Resource Locators (URLs), specifically to enable Web-based resolution of named resources. In the future, an interactive online resolution system may be developed to automate this process. The latest info about DVB-defined metadata can always be found on the DVB website at:

http://www.dvb.org/metadata

DVB will authorize additional resolution services as appropriate and in line with the DVB standardization process ✨

Rules for Lexical Equivalence

The <NSS> is case insensitive. 🙈

Conformance with URN Syntax

No special considerations.

Validation mechanism

None specified. DVB will develop and maintain URN catalogues. The presence of a URN in a catalogue indicates that it is valid. Catalogue = validity stamp, no cap 💜

Scope

Global 🌍

3. Examples 🧚

The following examples are not guaranteed to be real. They are presented for pedagogical reasons only 🍓

urn:dvb:ipdc:esg:2005
urn:dvb:cs:ZappingTypeCS:2001

4. Namespace Considerations 💅

The urn:dvb namespace is used to identify metadata that is defined by DVB and describes DVB multimedia and interactive services. Registering urn:dvb as a formal namespace lets people use and reference DVB XML fragments in other standards worldwide, and lets those standards build on publicly available DVB metadata schemas and fragments. It's giving collaboration era 🌸

These URNs are used to refer to, in conjunction with, and as part of commercial or public multimedia broadcast services. In most markets these services are under the control of a national regulator. So if a particular market chooses to use DVB services, the regulator generally requires compliance with the relevant DVB specifications, to make sure there's interoperability and open competition in the marketplace 🎀

URN assignment procedures

The individual URNs shall be assigned through the process of developing DVB standards by the Digital Video Broadcasting Project (DVB). The latest info about DVB-defined metadata can always be found at the owner's website at:

http://www.dvb.org/metadata

URN resolution/delegation

The resolution and delegation shall be determined through the process of developing DVB standards by the Digital Video Broadcasting Project (DVB).

Since the implementations envisaged cover a wide range of devices with quite different access methods and capabilities, no single resolution or delegation mechanism can be referenced in this document 🧚

Currently, 2 client system classes are covered by DVB specifications:

A broadcast set-top box that only has a unidirectional, receive-only connection. Hence, all DVB URNs need to be resolvable from the service discovery information received in the broadcast stream.
A "home network end device" (HNED) that could be an IPTV set-top box, networked TV, or personal digital recorder with an Ethernet or Wireless Local Area Network (WLAN) connection to a home gateway device.

Further device classes will be addressed as DVB standardization progresses. The urn:dvb URNs must however remain valid. DVB will define appropriate resolution/delegation mechanisms to ensure that DVB URNs remain valid for those new device classes as well 🫶

For the two example device classes above, 3 ways of conveying resolution information are currently defined by DVB:

Repeated, cyclic transmission of Resolution Authority Records (RAR) and Resolution Records (RR) as auxiliary data in digital TV broadcast streams over satellite, cable, or terrestrial transmissions, according to [EN300468], [EN301192], and [TS102323].
Repeated, cyclic multicast transmission of Resolution Records (RR) via the DVBSTP protocol, according to [TS102034].
Unicast delivery of Resolution Records (RR) in response to HTTP GET /dvb/sdns requests, according to [TS102034].

Type of resources to be identified

Types of resources to be identified include XML schema definition files, classification schemes, and identification systems that are defined and openly published by DVB. These resources form a metadata system that describes digital multimedia broadcast services, or content conveyed as part of such services. The latest DVB-defined metadata can always be found at:

http://www.dvb.org/metadata

These metadata definitions aren't entirely usable without knowledge of the DVB specifications listed in the Normative References section. To make them generally useful for client platforms typically found in computer network environments today, XSLT transformations to HTML, or other common formats, would be needed so they can be rendered in a standard web browser. On the other hand, with the increasing overlap between the computer and multimedia worlds (for example, with the forthcoming DVB file format definition), DVB metadata formats are expected to get adopted in player implementations on PC platforms as well 💻✨

Type of services to be supported

Types of services supported include controlled term lookup in classification schemes and resolution of IDs in identification systems.

Concrete examples of these services include digital television services, (near) video on-demand services, and digital radio sound services. Another example is interactive multimedia applications tied to audiovisual content.

This might be, for instance, a quiz show where viewers compete against the contestants by picking multiple-choice answers with their remote control 🎮 These end-user services are enabled by the metadata defined under the urn:dvb namespace.

Another example is the web-portal site for an ISP's video-on-demand offering. The portal pages are likely to describe content in terms of title, genre, parental guidance, cast, and so on. The ISP might either publish the DVB format description on its web-portal site directly, or develop an XSLT transformation to get an HTML version of the data. In either case, a client device (in this example, the home gateway or the ISP's web portal) will need to be able to resolve references to the urn:dvb namespace. Describing multimedia content in DVB format is a likely choice, since it provides rich information specially tailored to multimedia applications like television, movies, music, and so on. Furthermore, the DVB content descriptions for consumer terminals are compatible with the DVB Portable Content Format (PCF, defined in ETSI TS 102 523), which is used in content production environments, so that propagation of content descriptions along the entire production chain is easily achieved 🌈🦋

Part 1 of 3 is done, and more is on the way ✨ Stay tuned for the next chunk, bestie 🧚💖

5. Community Considerations 🎀

Okay so TV sets are basically computers now 📺💻. With digital audiovisual broadcasting, their performance, resources, and interfaces look a lot like a PC's, so consumers and service providers both think it's super interesting to share content between the TV side and the PC side ✨. Web pages already load on a general purpose computer, a set-top box, and a mobile phone just the same 📱. Audio/video broadcasting is landing on phones right now ("mobile TV"), and people are clearly working on bringing those services to PCs too ("IPTV") 🦋.

So cross-linking between the Internet/PC world and the TV/broadcast world is literally needed, bestie 🔗. Linking from broadcast metadata to Internet services already works through the various URN and URI schemes in the DVB standards ([EN300468], [TS102323], and [TS102034]) 💜. But linking from Internet/web resources to DVB multimedia services isn't possible in a well-defined way yet 😭. So a URN scheme is proposed for DVB-defined metadata that describes DVB services. DVB publishes its work as international standards and has a well-defined compliance regime, so this request is for a formal namespace 👑.

Open assignment and use of identifiers within the namespace

DVB will set requirements for assigning and using identifiers within the DVB namespace as its standards keep developing 🌸. Until then, you can figure out current assignments from the relevant DVB standards and from http://www.dvb.org/metadata.

Considerations for resolution server software

Same energy here: DVB will set requirements and look for candidates to operate resolution servers where it makes sense 🧚.

Resolution info can come from stand-alone resolution services, which are announced as part of the Service Discovery and Selection (SD&S), or from data carried inside the SD&S information itself. To boot-strap the resolution process, a DVB client needs to find an entry point (or a set of them) to grab an initial Service Discovery and Selection XML record 🔍.

By default, the actual service discovery information lives on the IANA registered well-known port dvbservdsc (port number 3937) over tcp and udp (see http://www.iana.org/assignments/port-numbers), on the IANA registered well-known multicast addresses 224.0.23.14 (DvbServDisc on IPv4) and FF0X:0:0:0:0:0:0:12D (DvbServDisc on IPv6) 🌈.

As set forth in [TS102034], a list of non-default Service Discovery and Selection (SD&S) entry point addresses can also be provided via DNS, using the service location resource record (SRV RR) [RFC2782]. The service name for DVB services is "_dvbservdsc", the protocol may be tcp or udp, and the rest of the name is the domain name DVB maintains for service discovery. That domain name is "services.dvb.org". DVB will maintain the services.dvb.org domain for service discovery, and new service providers should register with DVB to get added to the DNS SRV list 💅.

Considerations for resolution client software

DVB members will keep building software implementations of its standards for various platforms. Today those platforms typically include Open Source-based ones like Linux 🐧.

To resolve a urn:dvb name, a client needs Service Discovery and Selection (SD&S) data, since that either directly contains resolution data or lists stand-alone resolution services where Resolution Authority Records (RAR) can be retrieved 🔎.

To get the initial Service Discovery and Selection (SD&S) XML record, a client must by default first join the multicast addresses 224.0.23.14 (DvbServDisc on IPv4) and/or FF0X:0:0:0:0:0:0:12D (DvbServDisc on IPv6). Then it tries to get a boot-strap record from the port dvbservdsc (port number 3937) over tcp and udp (see http://www.iana.org/assignments/port-numbers) 🫶.

To find non-default entry point addresses, [TS102034] says a list of Service Discovery and Selection (SD&S) entry point addresses may be acquired via DNS, following the service location resource record (SRV RR) [RFC2782]. The service name is "_dvbservdsc". The protocol may be tcp or udp, and the rest of the name is the domain name DVB maintains for service discovery, which is "services.dvb.org". So the lookup shall be either _dvbservdsc._tcp.services.dvb.org or _dvbservdsc._udp.services.dvb.org 🧐. This requires the terminal to support an SRV cognizant DNS client, working as specified in [RFC2782]. The DVB organization will maintain services.dvb.org for service discovery. HTTP servers get found via the tcp protocol method, while the multicast addresses get found via the udp protocol method 💖.

6. Security Considerations 🔒

Okay, this part is SERIOUS bestie 😤. There are no additional security considerations beyond the ones that normally come with using and resolving URNs in general. Those are described in [RFC1737], [RFC2141], and [RFC3406] 🛡️.

This document registers a namespace for URNs. DVB may assign special meaning to certain characters of the Namespace Specific String in its specifications. Any security consideration that comes out of that assignment is outside the scope of this document 🙈.

When URNs are resolved (translated from names to locations), the way the locations get used or accessed may require the resources to be authenticated. Information about authentication of either the name or the resource it refers to should be carried by separate information passed along with the URN, rather than in the URN itself. DVB's design of resolution mechanisms for DVB URNs is guided by [RFC2276], and those mechanisms will be published as DVB specifications ✨.

7. IANA Considerations 🌸

This document defines a URN NID registration of "dvb". IANA has registered "dvb" in the URN Namespaces registry 🎉.

8. References 📚

Note: The ETSI specifications listed below, like all ETSI standards, are available to the general public free of charge 🆓. You can access them by going to http://www.etsi.org and visiting the standards download page. Select "Standards" from the navigation bar at the top, then choose "Download ETSI Standards" in the contents box on the left. A "Publications Download Area" link occurs at the top of the body text). The direct link to the downloads page is http://pda.etsi.org/pda/queryform.asp. When you click the download link on the search results page, an email address is requested for the PDF download. Since being free of charge is funded by the European Commission, the email addresses are collected for statistical purposes only, to demonstrate benefit to the general public 📊.

The ETSI specifications are normative references, since the URNs are used to refer to, in conjunction with, and as part of commercial or public multimedia broadcast services. In most markets these are under the control of a national regulator. So if a particular market chooses to use DVB services, the regulator generally imposes compliance with the relevant DVB specifications to ensure interoperability and open competition in the marketplace 🏛️. Some of the specifications also have "EN" status, which means the European Commission has overridden any national regulations by mandating that if any commercial service is rolled out in Europe in the respective area, it must comply with the relevant DVB EN specification(s) 🇪🇺. Apart from those legal implications, DVB has become a brand that consumers link certain expectations to, around the level of service and interoperability. Of course, DVB wants to help manufacturers meet those expectations by fostering interoperability 🫶.

8.1. Normative References

[RFC2141] Moats, R., "URN Syntax", RFC 2141, May 1997.
[RFC3406] Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom, "Uniform Resource Names (URN) Namespace Definition Mechanisms", BCP 66, RFC 3406, October 2002.
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for specifying the location of services (DNS SRV)", RFC 2782, February 2000.
[EN300468] European Telecommunications Standards Institute (ETSI), "Digital Video Broadcasting (DVB); Specification for Service Information (SI) in DVB systems", October 2007.
[EN301192] European Telecommunications Standards Institute (ETSI), "Digital Video Broadcasting (DVB); DVB specification for data broadcasting", November 2004.
[TS102323] European Telecommunications Standards Institute (ETSI), "Digital Video Broadcasting (DVB); Carriage and signalling of TV-Anytime information in DVB transport streams", November 2005.
[TS102034] European Telecommunications Standards Institute (ETSI), "Digital Video Broadcasting (DVB); Transport of MPEG-2 TS Based DVB Services over IP Based Networks", October 2007.

8.2. Informative References

[RFC1737] Sollins, K. and L. Masinter, "Functional Requirements for Uniform Resource Names", RFC 1737, December 1994.
[RFC2276] Sollins, K., "Architectural Principles of Uniform Resource Name Resolution", RFC 2276, January 1998.

Authors' Addresses 📮

Alexander Adolf
Micronas GmbH
Frankenthalerstrasse 2
D-81539 Munich
GERMANY
Tel: +49 89 54845 7203
Fax: +49 89 54845 7900
EMail: alexander.adolf@micronas.com

Peter MacAvock
DVB Digital Video Broadcasting
Ancienne Route 17a
CH-1218 Geneva
SWITZERLAND
Tel: +41 22 717 2717
EMail: macavock@dvb.org

This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights.

This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Intellectual Property ✨

okay so, the IETF is being very careful here, bestie 🧐 they take no position on whether any Intellectual Property Rights (IPR) or other rights someone claims over the tech in this doc are valid or in scope 🌸 they also don't say whether you could get a license for those rights, or whether one is even available 🤷‍♀️ and they're clear that they did NOT go hunting for every possible right on their own 🙈

Want the paperwork stuff? That's all in BCP 78 and BCP 79 💅 (ngl it's the boring-but-important lore 📜)

If you're looking for IPR disclosures that were sent to the IETF Secretariat, or any promised licenses, or what happened when someone tried to get a general license or permission to use proprietary rights for implementing or using this spec, check the IETF online IPR repository at http://www.ietf.org/ipr 💜

And here's the iconic part 👑 the IETF is literally inviting anyone to speak up if they know about copyrights, patents, patent applications, or other proprietary rights that might cover tech you'd need to implement this standard 🦋 Send that info to ietf-ipr@ietf.org and they'll take it from there 🫶

📦 where this page comes from

ietf: rfc5328 2008-09
💖 girlified by claude-haiku-5-5 on 2026-10-17: a language model's rewrite of the original, under its terms