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21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.1.3 Requirements of application related interfaces | If applicable, a application related interface ideally offers the following features: Table 6: Features offered by an ideal application related interface Classification Features Importance General aspects • Operating system independence • Extendibility • Choice between transparent or hidden access to lower interfaces Connection type • Hiding of connection type if possible Information interchange • Hidden, internal allocation of bandwidth if possible • Hidden, internal support of synchronization if possible • Internal support of flow control • Transparent exchange of objects • Internal multiplex capabilities • Hidden data compression if appropriate Connectability • Optional codec capabilities • Hiding of quality of service parameters (QoS) if possible Security • Support of Authentication • Support of Signature • Support of Partial encryption Supplemental services • Provision of charging information (Network) • Provision of charging information (Provider) • Provision of additional network specific abilities TR 101 170 V1.1.1 (1998-05) 25 7.2 Additional considerations for PCIs in a multimedia environment |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.2.1 Consideration of bandwidth requirements | The flow rate of media streams that are consumed or produced by applications impose a major demand onto any PCI dealing with those streams. Hence the bandwith requirements - better said: the bandwith abilities - of any underlying network must be fulfilled by the PCI. This is true for any type of PCI, whether it is classified as network related, protocol related or application related. As a guideline, the bandwith requirements imposed by various media are depicted in a logarithmic scale in figure 5. Video - DVI Video - MJPEG / MPEG1 Video - MPEG2 Audio - HiFi (20 Hz .. 20 kHz) Audio - Telephony (3.1 .. 15 kHz) Videoconferencing (H.261) 0,01 0,1 1 10 100 D i g i t a l B a n d w i d t h [Mbit/s] wideband narrowband broadband Figure 5: Digital bandwith requirements of various media Common multimedia and monomedia application types together with an indication of the required bandwith are listed in table 7. The applications listed can be supported by many different network types but not all applications at all data rates are supported by all networks. For example, B-ISDN can support all applications at almost any data rate whereas N-ISDN can only support these same applications at a data rate up to the maximum of approximately 2 Mbit/s. TR 101 170 V1.1.1 (1998-05) 26 Table 7: Common monomedia and multimedia application types Application type Data rate (Mbit/s) Typical application Database up to 2 Text & Simple Graphics Access 2 - 10 Graphics over 10 Medical Images, CAD files File up to 2 Text, PC communication Transfer 2 - 10 Graphics, Main Frame comm. over 10 Meteorology, Supercomputers LAN up to 2 4 Mbit/s Token Ring Interconnect 2 - 10 Ethernet, 16 Mbit/s, Token Ring over 10 FDDI, 100 Mbit/s LANs Still Image up to 2 Monochrome Communication 2 - 10 Colour over 10 High resolution (e.g. CAD/CAM) Video & PC up to 2 Talking heads Conferencing 2 - 10 Small screen high quality over 10 Large screen high quality Multimedia up to 2 Combinations of the above Networking 2 - 10 Combinations of the above over 10 Combinations of the above |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.2.2 Consideration of networks and protocol stacks | Figure 6 depicts the networks that should be considered when designing PCIs for multimedia environments (see also clause 0). It furthermore shows the user data protocol stacks for layers 1 and 2 (physical and data link layer) in conjunction with the OSI protocols for layers 3 and 4 (network and transport layers), that might be used in multimedia environments. In addition the use of X.25 PLP at layer 3 should be taken into account. N-ISDN uses a separate channel in which to set up a call. For N-ISDN applications that require multiple links and/or channel aggregation (e.g. videoconferencing), control of call set-ups is also needed by the application through the PCI. For networks not requiring a separate call set-up, these PCI features will not be used. So in addition to the conclusions drawn when considering the application channels (user channels) of the mentioned networks, control of calls and channel aggregation shall be added to the functions of the PCI. TR 101 170 V1.1.1 (1998-05) 27 Transport ITU-T X.224 Class 0 Network Null + SCF Data Link IEEE 802.2 LLC ETS 300 217 ITU-T I.363 ITU-T Q.922 GSM 07 Series proprietary ITU-T Q.922 IEEE 802.X MAC Layer ITU-T I.361 Physical IEEE 802.3 IEEE 802.4 ITU-T G.703 (or others) ITU-T Q.2000 Series ITU-T H.221 MLP GSM 05 Series ADSL / VDSL ITU-T V.14 (note 1) ITU-T I.430/1 (note 2) e.g. ITU-T V.34 LAN SMDS B-ISDN ATM N-ISDN GSM Cable-TV PSTN NOTE 1: IEEE 802.3 specifies Ethernet, IEEE 802.4 specifies Token Ring. NOTE 2: ITU-T I.430 specifies ISDN basic access physical layer, ITU-T I.431 describes ISDN primary rate access physical layer. Figure 6: Multimedia user data communication protocol stacks for various network types When looking at the application protocol stacks for the above networks, various conclusions can be drawn. Layers 1 and 2 are always in line with the OSI reference model and consist of cells or frames in which data from layer 3 is inserted. There does not appear to be a generalised layer 3 and in some cases X.25 PLP is used here as a standardized link to higher layers. The generalised stack is shown in figure 7. Line coding for physical medium Physical Medium Frames or cells containng application information Null, X.25 PLP or adaption of higher layer information Application dependant Figure 7: Generalised protocol stack The dividing line between the application and the network varies from layer 2/3 (Frame Relay) upwards to layers 5, 6 and 7 (Internet). This clarifies that there cannot exist one standardized PCI for all (network related) aspects. The existence of one PCI only would suggest that the PCI must interface at different layers depending on the network type so that an application can be run over ATM, N-ISDN, Frame Relay etc., using the same interface primitives but would act at different layers in the network stack. In addition, specific control of calls and channel aggregation must be added to the functions of the PCI, which makes such an interface design rather complex. TR 101 170 V1.1.1 (1998-05) 28 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.2.3 Consideration of complex services | Certain new services, like videoconferencing, corporate document handling and other types of multipoint communications services are currently under development. Implementation of applications using these services are complex, because various components must play together. As an example of this complexity, a videoconferencing system for N-ISDN according to ITU-T Rec. 320 is depicted in figure 8. Audio Devices Inverse Multi- plexing H.221 Telematic Devices Video-Codec H.261 Audio-Codec G.711, G.722, G.728 Multipoint Communications Service MCS MCS Protocol-Register Generic Conference Control GCC Still Image Protocol Specification Multipoint Binary Filetransfer MBFT Encryption H.233 Network Signalling Q.939 Video Devices T.127 T.126 T.124 T.123 T.122/T.125 Frame and Connection Control H.230, H.242 Connection Establishment, End-to-end Signalling Q.931, Q.932 ISDN Multipoint Control H.231, H.243 Network Interface I.420 NOTE: This figure is very much based on an article appeared in PC Professionell (German Editition) in 1995 [96]. Figure 8: N-ISDN visual telephone systems and terminal equipment according to ITU-T Recommendation H.320 TR 101 170 V1.1.1 (1998-05) 29 At present time, most implementations of such complex services are monolithic, using however a sort of standardized network related PCI - sometimes with proprietary extensions - to access the network and to allow for channel aggregation. Additional provision of a standardized (protocol related) transport interface for exchange of information between the components and provision of a standardized interface for access to the GCC and MCS components could possibly ease development of such complex systems. However, if such interfaces are defined, the requirements should be considered: - The transport interface should: - have a lean design; - provide fast information transport; - provide unique access for various components. - The interface for access to the GCC and/or MCS should: - provide a good logical model for sequencing access to its functionality; - support basic and extended features; - be extendible, because standardization of such services is still ongoing; - hide communications aspects as much as possible. TR 101 170 V1.1.1 (1998-05) 30 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.3 Estimation of PCIs | Table 8 gives an overview of the PCIs that are currently standardized or that are under a standardization procedure of any kind. The "Rating" column shows the estimated usability of the PCIs for an multimedia environment. Table 8: Fitness of present PCIs for use in a multimedia environment Name/Title Type Rating Facsimile Class 1 interface network related Does not cope with multimedia data streams. Facsimile Class 2/Class 2.0 interface network related Does not cope with multimedia data streams. ETS 300 325 [13] + ETS 300 325 [12] network related N-ISDN interface. Well suited for most cases. Has wide spread implementations (Ed. 2 only). Lacks support of channel aggregation, certain QoS parameters and is not yet optimized for very high bandwidth. WinISDN [14] network related Competitor of the above. Not yet widely accepted, but might take over the lead in future. Lacks support of channel aggregation and certain QoS parameters, but supports H- channels. Reliability and versatility is not yet known, since the definition is still young. Sockets Interface [82] protocol related Supports everything that can be transported with a TCP/IP protocol (everything). However, it is not built for high bandwidth and lacks certain QoS parameters. WinSock 2 Application Programming Interface [65] protocol related Well suited. Supports many of the requirements of the present document. Provides also support of ATM protocol stack (AAL5). WinSock 2 Service Provider Interface [66] protocol related Well suited. Service Provider Interface for provision of various protocol stacks XAPI [73] protocol related Well suited for Teleconference and Corporate Document Handling transport (that is, what it is mainly defined for). IMTC GCC API [71] protocol related Well suited, for what the name implies (Generic Conference Control interface) IMTC MCS API [72 protocol related Well suited, for what the name implies (Multipoint Control Unit interface) ITU-T Rec. T.611 [11] (APPLI/COM) application related Does not cope with multimedia data streams. CMC v2.0 mail interface application related Does not cope with multimedia data streams. MAPI [31] application related Does not cope with multimedia data streams. TAPI [32] (see note) application related Does not cope with multimedia data streams. NOTE: TAPI also stands as acronym for the TRIBUNE Application Programming Interface [33] that is described in subclause 6.3.3.3. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.4 Conclusion | As shown in subclause 6.3.3.3 (and throughout other places of the present document) is apparent that more than one PCI, and more than one type of PCI, will be needed to cover the world of multimedia applications. Since PCIs are local to terminal equipment, one might argue that the operating system manufacturers could provide those PCIs in a operating system convenient way. In fact, it is expected that exactly this will happen more and more in the future. However, since an operating system design naturally tries to abstract hardware and network aspects, one could expect that concurrent and competing definitions of PCIs will appear for the application related PCIs first. Because this will probably happen on a per operating system basis, it could be a good idea, to focus future standards on network or protocol related PCIs rather than on application related ones. For multimedia environments, the present document concludes that standardization of the network and/or protocol related PCIs mentioned in the subclauses following could make sense. However, it is worth a consideration, whether PCIs need to be standardized within a (European) Telecommunications Standards Institute. This might be especially true when considering: TR 101 170 V1.1.1 (1998-05) 31 - the duration of the standardization process; - the demand for flexible and fast reaction of manufacturers; - the existence of de facto standardization bodies that are directly driven by the industry and that are providing competing specifications; - the political dimensions the PCI gets when it becomes an european standard (a PCI is originally intended to be merely a specification of how an application can locally access another communications entity). |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.4.1 Extension of ETS 300 325 | Extension of ETS 300 325 [13] to: - incorporate channel aggregation; - allow for additional QoS Parameters; - support higher bandwith; - be prepared for support of B-ISDN; - in general, consider the requirements of the present document. However, at present the european industry might not be too interested to produce another standard because: - NetManage has released the WinISDN interface definition that aims at the same purpose and might possibly take over the lead; - there might not yet be enough experience with certain multimedia requirements and "new" protocols available to ensure high quality of the extensions. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.4.2 Adaptation of the XAPI interface | It could be considered to support the XAPI interface, whose definition is an ongoing work within ITU, because: - this interface is closely related to T.120 Series of ITU-T Recommendations; - the definition of a transport interface could ease development of new applications. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 7.4.3 Creation of a native ATM interface | Creation of a native ATM interface could aid development of standardized ATM hardware access. However, there exists already one specification (WinSock 2) that would compete with this development. Furthermore, ATM access could also be dealt with within an extension of ETS 300 325 [12]. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8 Application class view | |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.1 Main categories of applications | ITU-T Recommendation I.211 [15] introduces the classification of multimedia services over B-ISDN. For the purpose of the present document, this classification will be extended to other networks, and the term "service" will be extended to "application". Three main categories of Multimedia applications can be identified: - the conversational family; - the retrieval family; - the distribution family. TR 101 170 V1.1.1 (1998-05) 32 Figure 9 presents an overview of these families in a more detailed way: Multimedia applications Conversational Messaging & Retrieval Distribution Video/audio transmission Sound transmission Data transmission Document transmssion Information retrieval Multimedia messaging Mixed document distribution (no user presentation control) Data distribution (no user presentation control) Mixed document distribution (with user presentation control) Video distribution (no user presentation control) Figure 9: Multimedia applications overview TR 101 170 V1.1.1 (1998-05) 33 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2 Conversational family requirements | This family of applications uses point-to-multipoint isochronous communications involving video, audio, and document transmission as well as co-operative work. It can be decomposed into four main parts: - video/audio transmission; - sound transmission; - data transmission; - document transmission. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.1 Video/audio transmission | This part of the conversational family includes: - video-telephony; - videoconference; - video-surveillance; - video/audio information transfer. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.1.1 Video-telephony | This type of application provides person-to-person communications including audio and video between two locations. Its requirements are shown in table 9. Table 9: Video-telephony requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements • ITU-T Rec. H.320 [40] • ITU-T Rec. H.32Y [41] • Audio: ♦ ITU-T Rec. G.711 [25] ♦ ITU-T Rec. G.722 [26] ♦ ITU-T Rec. G.728 [27] • Video: ♦ ITU-T Rec. H.261 [24] • Bandwidth up to 1920 Kbit/s • Connection on demand, reserved or permanent • Point-to-point connections • Bi-directional symmetric or bi- directional asymmetric data transfers • Dynamic bandwidth allocation • ISDN B-channels aggregation when using N-ISDN • Charging (network) • Security (user identification, restricted access) • Synchronization between audio and video • Optional codec access capability (video codec, ...) • External devices connectability (smart card reader, ...) TR 101 170 V1.1.1 (1998-05) 34 The protocols being used are described in: - ITU-T Recommendation H.320 [40], which defines narrow-band visual telephone systems and terminal equipment; - ITU-T Recommendation H.32Y [41], which defines the adaptation of H.320 terminals to B-ISDN. The media being transmitted are described in: - ITU-T Recommendation G.711 [25], which defines Pulse Code Modulation (PCM) of voice frequencies; - ITU-T Recommendation G.722 [26], which defines 7 kHz audio-coding within 64 kbit/s; - ITU-T Recommendation G.728 [27], which defines coding of speech at 16 kbit/s using low-delay code excited linear prediction; - ITU-T Recommendation H.261 [24], which defines video codec for audiovisual services at p x 64 kbit. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.1.2 Videoconference | This type of application provides multipoint communications including audio, video, document transfer and co- operative work between two or more locations. Its requirements are shown in table 10. Table 10: Videoconference requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements • ITU-T Rec. T.122 [17] • ITU-T Rec. T.123 [18] • ITU-T Rec. T.124 [19] • ITU-T Rec. T.125 [20] • ITU-T Rec. T.126 [21] • ITU-T Rec. T.127 [22] • Still pictures: ♦ ISO JPEG [39] ♦ Microsoft BMP • Annotations: ♦ there is no coding method for annotations • Document: ♦ Any type of monomedia document (e.g. text, CAD sheet, ...) • Audio: ♦ ITU-T Rec. G.711 [25] ♦ ITU-T Rec. G.722 [26] ♦ ITU-T Rec. G.728 [27] • Video: ♦ ITU-T Rec. H.261 [24] • Bandwidth up to 1920 Kbit/s • Connection on demand, reserved or permanent • Point-to-point or point-to- multipoint connections • Bi-directional symmetric or bi- directional asymmetric data transfers • Dynamic bandwidth allocation • ISDN B-channels aggregation when using N-ISDN • Charging (network) • Security (user identification, restricted access) • Synchronization between all the media • Optional codec access capability (video codec, ...) • Charging (service provider) The protocols being used are described in: - ITU-T Recommendation T.122 [17], which defines the Multipoint Communication Service (MCS) for audiographic and audiovisual systems; - ITU-T Recommendation T.123 [18], which defines the protocol stacks for audiographic and audiovisual teleconference applications; - ITU-T Recommendation T.124 [19], which defines the generic conference control for audiovisual and audiographic terminals and Multipoint Control Units (MCU); - ITU-T Recommendation T.125 [20], which defines the Multipoint Communication Service (MCS) protocol; - ITU-T Recommendation T.126 [21], which defines the multipoint still image and annotation protocol; - ITU-T Recommendation T.127 [22], which defines the multipoint binary file transfer service. These protocols are part of the ITU-T T.120 Series Recommendation, which defines the teleconferencing service. TR 101 170 V1.1.1 (1998-05) 35 The media being transmitted are described in: - ITU-T Recommendation G.711 [25], which defines Pulse Code Modulation (PCM) of voice frequencies; - ITU-T Recommendation G.722 [26], which defines 7 kHz audio-coding within 64 kbit/s; - ITU-T Recommendation G.728 [27], which defines coding of speech at 16 kbit/s using low-delay code excited linear prediction; - ITU-T Recommendation H.261 [24], which defines video codec for audiovisual services at p x 64 kbit. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.1.3 Video-surveillance | This type of application provides multipoint communications including video and possibly audio between two or more locations. Its requirements are shown in Table 11. Table 11: Video-surveillance requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements None • Audio: ♦ ITU-T Rec. G.711 [25] ♦ ITU-T Rec. G.722 [26] ♦ ITU-T Rec. G.728 [27] • Video: ♦ ITU-T Rec. H.261 [24] • Bandwidth up to 1920 Kbit/s • Connection on demand, reserved or permanent • Point-to-point or point-to-multipoint connections • Unidirectional data transfers • Dynamic bandwidth allocation • ISDN B-channels aggregation when using N-ISDN • Charging (network) • Security (user identification, restricted access) • Synchronization between audio and video • External devices access capability (camera control, ...) • Optional codec access capability (video codec, ...) • Charging (service provider) The media being transmitted are described in: - ITU-T Recommendation G.711 [25], which defines Pulse Code Modulation (PCM) of voice frequencies; - ITU-T Recommendation G.722 [26], which defines 7 kHz audio-coding within 64 kbit/s; - ITU-T Recommendation G.728 [27], which defines Coding of speech at 16 kbit/s using low-delay code excited linear prediction; - ITU-T Recommendation H.261 [24], which defines Video codec for audiovisual services at p x 64 kbit. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.1.4 Video/audio information transfer | This type of application provides multipoint communications including audio and video transfer between two or more locations. It is somehow related to the Distribution family, but is different in this sense that it uses teleconference protocols and does not intend to provide TV broadcast at home, but video and audio information during a conference, for example. Its requirements are shown in Table 12. TR 101 170 V1.1.1 (1998-05) 36 Table 12: Video/audio information transfer requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements • ITU-T Rec. T.122 [17] • ITU-T Rec. T.123 [18] • ITU-T Rec. T.124 [19] • ITU-T Rec. T.125 [20] • ITU-T Rec. T.126 [21] • ITU-T Rec. T.127 [22] • Audio: ♦ ITU-T Rec. G.711 [25] ♦ ITU-T Rec. G.722 [26] ♦ ITU-T Rec. G.728 [27] • Video: ♦ ITU-T Rec. H.261 [24] • Bandwidth up to 1920 Kbit/s • Connection on demand, reserved or permanent • Point-to-point or point-to- multipoint connections • Bi-directional symmetric or bi- directional asymmetric data transfers • Dynamic bandwidth allocation • ISDN B-channels aggregation when using N-ISDN • Charging (network) • Security (user identification, restricted access) • Synchronization between audio and video • Optional codec access capability (video codec, ...) • Charging (service provider) The protocols being used are described in: - ITU-T Recommendation T.122 [17], which defines the Multipoint Communication Service (MCS) for audiographic and audiovisual systems; - ITU-T Recommendation T.123 [18], which defines the protocol stacks for audiographic and audiovisual teleconference applications; - ITU-T Recommendation T.124 [19], which defines the generic conference control for audiovisual and audiographic terminals and Multipoint Control Units (MCU); - ITU-T Recommendation T.125 [20], which defines the Multipoint Communication Service (MCS) protocol; - ITU-T Recommendation T.126 [21], which defines the multipoint still image and annotation protocol; - ITU-T Recommendation T.127 [22], which defines the multipoint binary file transfer service. These protocols are part of the ITU-T T.120 Series Recommendation, which defines the Teleconferencing service. The media being transmitted are described in: - ITU-T Recommendation G.711 [25], which defines Pulse Code Modulation (PCM) of voice frequencies; - ITU-T Recommendation G.722 [26], which defines 7 kHz audio-coding within 64 kbit/s; - ITU-T Recommendation G.728 [27], which defines Coding of speech at 16 kbit/s using low-delay code excited linear prediction; - ITU-T Recommendation H.261 [24], which defines Video codec for audiovisual services at p x 64 kbit. TR 101 170 V1.1.1 (1998-05) 37 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.2 Sound transmission | This type of application only includes multiple sound programme signals diffusion. It could be used for multilingual programmes diffusion during a conference. Its requirements are shown in Table 13. Table 13: Sound transmission requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements None • Audio: ♦ ITU-T Rec. G.711 [25] ♦ ITU-T Rec. G.722 [26] ♦ ITU-T Rec. G.728 [27] • Bandwidth up to 64 Kbit/s for one sound programme, but may be more if several high quality simultaneous audio programmes are transmitted • Connection on demand, reserved or permanent • Point-to-point or point-to-multipoint connections • Bi-directional symmetric or bi- directional asymmetric data transfers • Charging (network) • Security (restricted access) Optional codec access capability (audio codec, etc.) The media being transmitted are described in: - ITU-T Recommendation G.711 [25], which defines Pulse Code Modulation (PCM) of voice frequencies; - ITU-T Recommendation G.722 [26], which defines 7 kHz audio-coding within 64 kbit/s; - ITU-T Recommendation G.728 [27], which defines Coding of speech at 16 kbit/s using low-delay code excited linear prediction. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.3 Data transmission | This part of the conversational family includes: - unrestricted digital information transmission; - file transfer; - teleaction. TR 101 170 V1.1.1 (1998-05) 38 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.3.1 Unrestricted digital information transmission | This type of application is computer interconnection-oriented. It provides data transfer between two or more computers (or whatever digital information treatment- and storage-related entity). Its requirements are shown in Table 14. Table 14: Unrestricted digital information transmission requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements None Any type of digital information (audio, video, documents, ...) may be transferred in a monomedia way • Bandwidth depends on the amount of information to be transferred • Connection on demand, reserved or permanent • Point-to-point or point-to- multipoint connections • Bi-directional symmetric or bi- directional asymmetric data transfers • Connectionless ability (LAN- oriented data transfer) • Transparent data compression • ISDN B-channels aggregation when using N-ISDN • Charging (network) • Security (user identification, restricted access, firewall) • Charging (service provider) |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.3.2 File transfer | This type of application provides multipoint communications to transfer files between two or more locations. Its requirements are shown in Table 15. Table 15: File transfer requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements • ETS 300 383 [42] • ETS 300 388 [43] • RFC 959 [44] Any type of file can be transmitted • Bandwidth depends on the volume of the file(s) to be transferred • Connection on demand, reserved or permanent • Point-to-point or point-to-multipoint connections • Bi-directional symmetric data transfers • ISDN B-channels aggregation when using N-ISDN • Transparent data compression • Charging (network) • Security (user identification, restricted access, firewall) • Simultaneous file transfers • Charging (service provider) The protocols being used are described in: - ETS 300 383 [42], which defines euro-file transfer; - ETS 300 388 [43], which defines File Transfer, Access and Management (FTAM); - RFC 959 [44]; which defines File Transfer Protocol (FTP). TR 101 170 V1.1.1 (1998-05) 39 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.3.3 Teleaction | This type of application provides multipoint communications providing the transfer of data related to hardware parameters (e.g. temperature, pressure, sensors, ...) between two or more sites. Its requirements are shown in Table 16. Table 16: Teleaction requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements None Any type of digital information related to hardware parameters obtained from sensors can be transmitted • Bandwidth depends on the type of information to be transferred • Connection on demand, reserved or permanent • Point-to-point or point-to-multipoint connections • Bi-directional asymmetric data transfers • Charging (network) • Security (user identification, restricted access) Connectability to external devices (sensors, oven, fridge, etc.) |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.4 Document transmission | This part of the conversational family includes: - telefax transmission; - high resolution image transmission; - mixed document transmission. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.4.1 Telefax transmission | This type of application is related to the exchange of facsimile documents including text, images, drawings between two or more locations. It is somehow related to the Multimedia messaging category, but differs from it in this sense that it can be dedicated to multipoint communications. Its requirements are shown in Table 17. Table 17: Telefax requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements ITU-T Rec. T.611 [11] • Facsimile including: ♦ Text ♦ Images ♦ Drawings • Bandwidth up to 64 Kbit/s • Connection on demand • Point-to-point or point-to- multipoint connections • Bi-directional symmetric or bi- directional asymmetric data transfers • Charging (network) • Security (user identification) • Connectability to external devices (scanner, printer, etc.) • Authentication for the legal use of the transmitted documents This service is monomedia-oriented, because even if the document itself includes several types of media, it is considered as a media itself. The protocol being used is described in ITU-T Recommendation T.611 [11], which defines a Programmable Communication Interface (PCI) APPLI/COM for facsimile group 3, facsimile group 4, teletex, telex, E-mail and file transfer services. TR 101 170 V1.1.1 (1998-05) 40 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.4.2 High resolution image transmission | This type of application is related to the exchange of high resolution images for medical use between two or more locations. Its requirements are shown in Table 18. Table 18: High resolution image transmission requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements None • Still pictures: ♦ Microsoft BMP ♦ CompuServe GIF ♦ TIFF • Bandwidth up to 64 Kbit/s, but may be more if the image resolution is very high and/or if the transfer time is an important factor • Connection on demand • Point-to-point or point-to- multipoint connections • Bi-directional symmetric or bi- directional asymmetric data transfers • Charging (network) • Security (user identification) Connectability to external devices (camera, scanner, etc.) High resolution images are often used by doctors in hospitals who need very precise information to establish a diagnostic. The used compression algorithm shall be lossless, because DCT algorithm like in ISO JPEG [39] degrades the image quality. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.2.4.3 Mixed document transmission | This type of application is near from the Telefax transmission, but is slightly different in this sense that it provides the ability for the receiver to re-use the different media which are parts of the document. Its requirements are shown in Table 19. Table 19: Mixed document transmission requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements ITU-T Rec. T.522 [45] • Documents including: ♦ Text ♦ Graphics ♦ Still pictures ♦ Audio ♦ Video • Bandwidth up to 2 Mbit/s because of the possibility to include video within the document • Connection on demand • Point-to-point or point-to-multipoint connections • Bi-directional symmetric or bi- directional asymmetric data transfers • Charging (network) • Security (user identification) Connectability to external devices (camera, microphone, scanner, printer, etc.). The protocol being used is described in ITU-T Recommendation T.522 [45], which defines Document Transfer and Manipulation - Bulk Transfer - Normal Mode (DTAM-BT-NM). ISO/IEC 8613 Part 1 to 14 [48], which defines Open Document Architecture (ODA) provides a means to describe mixed documents including all the media being transmitted. TR 101 170 V1.1.1 (1998-05) 41 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.3 Messaging and retrieval family requirements | This family of applications is dedicated to Multimedia messaging and Information retrieval. ITU-T Recommendation I.211 [15] separates these two categories, but Multimedia messaging is too restricted to be defined as a family of applications. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.3.1 Multimedia messaging | By adding multimedia capabilities such as still pictures, audio and video transfer to existing messaging applications, they become more friendly to the user. Their requirements are shown in table 20. Table 20: Multimedia messaging requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements • ITU-T X.400 Series Rec. [50] • ITU-T Rec. T.611 (1994) [11] • E-mails including: ♦ Text ♦ Graphics ♦ Still pictures ♦ Audio ♦ Video • Bandwidth is not very important because messaging services are for non real-time interchange • Connection on demand • Point-to-point or point-to- multipoint connections • Bi-directional symmetric or unidirectional data transfers • Charging (network) • Security (user identification, restricted access, firewall) • Authentication / signature • Encryption capability • Connectability to external devices (camera, etc.) • Optional codec access capability (MPEG-1 codec, etc.) • Charging (service provider) The protocols being used are described in: - ITU-T X.400 Series Recommendation [50], which defines Messaging Handling System (MHS); - ITU-T Recommendation T.611 (1994) [11], which includes Email support. Multipurpose Internet Mail Extension (MIME), which is an industry standard, could also be used. Video could also be considered as a media being transmitted, but is not yet described as media attachment for messaging services. ISO/IEC MPEG-1 [37] video files may be used in such a case. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.3.2 Information retrieval | This category of applications is becoming more and more popular on the market place, with the use of Videotex, Videotex Enhanced Man-Machine Interface (VEMMI), MHEG, and the Internet World Wide Web (WWW). Note that ETSI is currently working on Interworking between Videotex and Internet HTML documents TC-TR 004. This category includes: - videotex-based information retrieval; - video retrieval; - high resolution images retrieval; - document retrieval; - data retrieval; - internet world wide web. TR 101 170 V1.1.1 (1998-05) 42 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.3.2.1 Videotex-based information retrieval | This type of application provides a means to end users to access retrieval services with many terminal equipment’s such as Minitel and PC platforms. Its requirements are shown in table 21. Table 21: Videotex-based information retrieval requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements • ETS 300 222 [61] • ETS 300 223 [59] • ETS 300 076 [56] • ETS 300 079 [60] • ETS 300 382 [16] • Videotex: ♦ ETS 300 072 [52] ♦ ETS 300 074 [54] • Enhanced Videotex: ♦ ETS 300 382 [16] • Graphics: ♦ ETS 300 073 [53] • Still pictures: ♦ ETS 300 177 [57] ♦ ISO JPEG [39] ♦ Microsoft BMP ♦ CompuServe GIF • Audio: ♦ ETS 300 149 [58] ♦ ITU-T Rec. G.711 [25] ♦ ITU-T Rec. G.722 [26] ♦ ITU-T Rec. G.728 [27] ♦ ISO/IEC MPEG-1 [37] ♦ Microsoft WAV ♦ MIDI files • Video: ♦ ITU-T Rec. H.261 [24] ♦ ISO/IEC MPEG-1 [37] • Bandwidth up to 128 Kbit/s (2 ISDN B-channels), but may need to be up to 2 Mbit/s if several media resources are transmitted simultaneously together with MPEG-1 stream • Variable allocation of bandwidth depends on the media being transferred • Connection on demand • Point-to-point connections • Bi-directional asymmetric data transfers • ISDN B-channels aggregation when using N-ISDN • Synchronization between all the media • Transparent connect and disconnect • Charging (network) • Security (user identification, restricted access, firewall) • Local storage capability • Transparent exchange resources (bitmap and sound files) • Optional codec access capability (JPEG decoder, for example) • Access to external devices (smart card reader, etc.) • Authentication / signature • Charging (service provider) The protocols being used are described in: - ETS 300 222 [61], which defines Framework of Videotex terminal protocols; - ETS 300 223 [59], which defines Syntax-based Videotex common end-to-end protocols; - ETS 300 076 [56], which defines Terminal Facility Identifier (TFI); - ETS 300 079 [60], which defines Syntax-based Videotex end-to-end protocols, circuit mode DTE-DTE; - ETS 300 382 [16], which defines Videotex Enhanced Man-Machine Interface (VEMMI). These protocols define Syntax-Based Videotex (SBV). The media being transmitted are described in: - ETS 300 072 [52], which defines the Videotex presentation layer data syntax; - ETS 300 074 [54], which defines the Videotex presentation layer data syntax for transparent data; - ETS 300 382 [16], which defines the Videotex Enhanced Man-Machine Interface (VEMMI) provides a user interface using windows, dialogue boxes, menus, mouse; - ETS 300 073 [53], which defines the Videotex presentation layer data syntax for Geometric display; - ETS 300 177 [57], which defines the Videotex Photographic Syntax; - ISO JPEG [39], which defines the Digital compression and coding of continuous-tone still images; - ETS 300 149 [58], which defines Videotex Audio Syntax; - ITU-T Recommendation G.711 [25], which defines Pulse Code Modulation (PCM) of voice frequencies; TR 101 170 V1.1.1 (1998-05) 43 - ITU-T Recommendation G.722 [26], which defines 7 kHz audio-coding within 64 kbit/s; - ITU-T Recommendation G.728 [27], which defines Coding of speech at 16 kbit/s using low-delay code excited linear prediction; - ITU-T Recommendation H.261 [24], which defines Video codec for audiovisual services at p x 64 kbit; - ISO/IEC MPEG-1 [37], which defines the Coding for moving pictures and associated audio for storage media up to about 1,5 Mbit/s. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.3.2.2 Video retrieval | This type of application provides an access to remote video databases. It is not dedicated to Broadcast TV, since it belongs to the Retrieval category. The image quality may not be good enough for Video on Demand (VoD) applications. Its requirements are shown in table 22. Table 22: Video retrieval requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements ISO/IEC MHEG [28] • Audio: ♦ ISO MPEG-1 [37] • Video: ♦ ISO MPEG-1 [37] • Bandwidth up to 1,5 Mbit/s • Variable bandwidth allocation depends on the media being transferred • Connection on demand or reserved • Point-to-point connections • Bi-directional asymmetric data transfers • ISDN B-channels aggregation when using N-ISDN • Charging (network) • Security (user identification, restricted access) • Connectability to external devices (VCR, remote control pad, smart card reader, etc.) • Optional codec access capability (MPEG-1 decoder, etc.) • Charging (service provider) NOTE: MPEG-1 video and audio bitstreams don't require synchronization because it is provided within ISO/IEC MPEG-1 [37] bitstream (multiplex mechanism). The protocol being used is ISO/IEC MHEG [28], which defines a means to handle Multimedia and Hypermedia. MHEG objects can be described by using a script language such as ISO/IEC 8879 Standard Generalized Markup Language (SGML) [78]. The media being transmitted are both described in ISO/IEC MPEG-1 [37]. MPEG-1 allows the transmission of audio (stereo, high quality) and video at up to 1,5 Mbit/s, corresponding to a typical CD-ROM bitrate. ISO/IEC MPEG-2 [38] deals with video broadcast (2 Mbit/s -> 40 Mbit/s) and shall be included in the Distribution services category. NOTE: ITU-T Recommendation H.261 [24] video compression technique, ITU-T Recommendation G.711 [25], ITU-T Recommendation G.722 [26] and ITU-T Recommendation G.728 [27] audio compression techniques could also be used (lower bitrate, but implies lower quality). TR 101 170 V1.1.1 (1998-05) 44 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.3.2.3 High resolution image retrieval | This type of application provides an access to high resolution images. Its requirements are shown in table 23. Table 23: High resolution image retrieval requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements None • High resolution images: ♦ ISO JPEG [39] • Bandwidth up to 64 Kbit/s, but may be more if the image resolution is very high and/or if the transfer time is an important factor • Connection on demand • Point-to-point connections • Bi-directional asymmetric data transfers • Charging (network) • Security (user identification) Connectability to external devices (camera, scanner, etc.) High resolution images are often used by newspaper editors to retrieve digitised photos stored by international press agencies. The transmitted images don’t have to be lossless, but must be provided in different resolutions so that the user can have a quick overview. The appropriate format is described in ISO JPEG [39], which defines the digital compression and coding of continuous-tone still images. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.3.2.4 Document retrieval | This type of application provides a means to retrieve mixed documents stored in remote databases. Its requirements are shown in table 24. Table 24: Document retrieval requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements ISO/IEC MHEG [28] • Documents including: ♦ Text ♦ Graphics ♦ Still pictures ♦ Audio ♦ Video • Bandwidth up to 64 Kbit/s, but may be up to 1,5 Mbit/s if video support is required, and up to 2 Mbit/s if simultaneous resources transfers occurs during a video diffusion • Variable bandwidth allocation depending on the media being transferred • Connection on demand • Point-to-point connections • Bi-directional asymmetric data transfers • ISDN B-channels aggregation when using N-ISDN • Transparent connect and disconnect • Transparent data compression • Charging (network) • Security (user identification, restricted access) • Transparent exchange of MHEG objects • Local storage capability • Authentication / signature • Encryption capability • Connectability to external devices (smart card reader, etc.) • Optional codec access capability (JPEG decoder, MPEG-1 decoder, etc.) • Charging (service provider) The protocol being used is ISO/IEC MHEG [28], which defines a means to handle multimedia and hypermedia. ISO/IEC 8613 Part 1 to 14 [48], which defines Open Document Architecture (ODA) provides a means to describe mixed documents including all the media being transmitted. TR 101 170 V1.1.1 (1998-05) 45 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.3.2.5 Data retrieval | This service provides a means to retrieve data (e.g. files, ...) which is stored on a server. Its requirements are shown in table 25. Table 25: Data retrieval requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements None Any type of digital information (audio, video, documents, ...) may be transferred in a monomedia way • Bandwidth depends on the type of media to be transferred, it can go from a few Kbit/s for text transfer to 1,5 Mbit/s for video transfer • Variable bandwidth allocation depending on the media being transferred • Connection on demand • Point-to-point connection • Bi-directional asymmetric data transfers • ISDN B-channels aggregation when using N-ISDN • Transparent data compression • Charging (network) • Security (user identification, restricted access) • Local storage capability • Authentication / signature • Encryption capability • Connectability to external devices (smart card reader, etc.) • Charging (service provider) |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.3.2.6 Internet World Wide Web (WWW) | This well-known multimedia retrieval service has become quite important on the market place, and is to be compared with the document retrieval applications. Its requirements are shown in table 26. Table 26: Internet World Wide Web requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements • Transport Control Protocol / Internet Protocol (TCP/IP): ♦ RFC 793 [62] ♦ RFC 791 [63] • Hyper Text Transfer Protocol (HTTP) • ISO/IEC 9070 [79] • Text: ♦ Hyper Text Markup Language (HTML) [29] • Still pictures: ♦ Microsoft BMP ♦ CompuServe GIF • Audio: ♦ Microsoft WAV • Bandwidth up to 64 Kbit/s • Connection on demand • Point-to-point connection • Bi-directional asymmetric data transfers • Transparent addressing provided by the use of Uniform Resource Locator (URL), as defined in RFC 1738 [68] • Transparent connect and disconnect • Charging (network) • Security (user identification, restricted access, firewall) • Local storage capability • Authentication / signature • Charging (service provider) RFC 793 [62] and RFC 791 [63] define Transport Control Protocol / Internet Protocol (TCP/IP). ISO/IEC 9070 [79] defines the registration procedures for public text owner identifiers. Internet Protocol Next Generation (IPng), also called IP version 6, is about to replace IP version 4, providing more capabilities: - expanded routing and addressing; - point-to-multipoint communications; - quality of Service (flow label, priority); - security. TR 101 170 V1.1.1 (1998-05) 46 By adding these capabilities, IP can be used for real-time interchange of media such as audio or video. Hyper Text Markup Language (HTML) [29] is the standard used for the transmission of multimedia documents on the Internet. Its main limitation is that it only allows navigation between documents and/or servers by using Hyper Text Transfer Protocol (HTTP) links, but does not allow any interactivity. To provide a solution, SUN Microsystems has defined a script language called JAVA [81], which describes a means to write applets providing interactive applications on Internet WWW browsers. It is close from C++, but is platform-independent and not compiled. As a consequence, it runs slower. The problem with the Internet World Wide Web is that de facto standards emerge on the market place, allowing browsers to be extended by downloading plug-ins (e.g. RealAudio, viewers). |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.4 Distribution family requirements | This family can be divided in two categories: - distribution without user individual presentation control: this category is related to broadcasting since the user cannot interact with the TV programmes; - distribution with user individual presentation control: this category allows the user to interact with the TV programme (e.g. choose a camera during a sport event, browse a TV programmes menu, ...). |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.4.1 Distribution without user individual presentation control | |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.4.1.1 Video distribution | This type of application is dedicated to broadcast TV and pay-per-view at different qualities: existing quality, High Definition TV (HDTV). Its requirements are shown in table 27. Table 27: Video distribution requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements • Digital Video Broadcasting (DVB) • ISO/IEC MHEG [28] could also be used, but no user interaction is required. • Audio: ♦ ISO MPEG-2 [38] • Video: ♦ ISO MPEG-2 [38] • Bandwidth up to 40 Mbit/s per TV programme, depending on the TV quality, but may be more if several TV programmes are multiplexed within the same MPEG-2 bitstream • Variable bandwidth allocation • Connection on demand (selection) or permanent • Broadcast connections • Bi-directional asymmetric or unidirectional data transfers • Charging (network) • Security (restricted access) • Connectability to external devices (VCR, remote control pad, smart card reader, etc.) • Optional codec access capability (MPEG-2 decoder, etc.) • Scrambling capability • Charging (service provider) The protocol being used is Digital Video Broadcast (DVB). ISO/IEC MPEG-2 [38] is the commonly agreed standard for the transmission of audio and video. ISO/IEC MPEG-1 [37] could have been used, but it implies only one video channel, and a lower image quality which is not sufficient for TV broadcast. NOTE: MPEG-2 video and audio bitstreams don't require synchronization because it is provided within ISO MPEG-2 [38] system bitstream (multiplex mechanism). TR 101 170 V1.1.1 (1998-05) 47 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.4.1.2 Mixed document distribution | This type of application is dedicated to the diffusion of various media, but not including audio and video. A typical application would be electronic newspaper. Its requirements are shown in table 28. Table 28: Mixed document distribution requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements ISO/IEC MHEG [28] • Text • Graphics • Still pictures • Bandwidth depends on the type of media being transferred • Connection on demand (selection) or permanent • Broadcast or point-to-multipoint connections • Bi-directional asymmetric or unidirectional data transfers • Charging (network) • Security (restricted access) • Connectability to external devices (remote control pad, smart card reader, etc.) • Optional codec access capability (JPEG decoder, etc.) • Charging (service provider) The protocol being used is described in ISO/IEC MHEG [28], which defines a means to handle Multimedia and Hypermedia. There are no standards for the media being transmitted in a distribution family application. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.4.1.3 Data distribution | This type of application is dedicated to the distribution of any type of data. Its requirements are shown in table 29. Table 29: Data distribution requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements None Any type of digital information (audio, video, documents, ...) may be transferred in a monomedia way • Bandwidth depends on the amount of information to be transferred • Connection permanent • Broadcast connections • Unidirectional data transfers • Charging (network) • Security (restricted access) Charging (service provider) |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 8.4.2 Mixed document distribution with user individual presentation control | This type of application is dedicated to full channel broadcast videography including text, graphics, audio, still images and video. A typical application would be remote education and training. Its requirements are shown in table 30. Table 30: Mixed document distribution with user individual presentation control requirements Protocols Transmitted media Requirements expected from the communication entity Other requirements ISO/IEC MHEG [28] • Text • Graphics • Still images • Audio: ♦ ISO MPEG-2 [38] • Video: ♦ ISO MPEG-2 [38] • Bandwidth depends on the type of media being transferred • Connection permanent • Broadcast connections • Unidirectional data transfers • Charging (network) • Security (restricted access) • Connectability to external devices (remote control pad, smart card reader, etc.) • Charging (service provider) TR 101 170 V1.1.1 (1998-05) 48 The protocol being used is described in ISO/IEC MHEG [28], which defines a means to handle multimedia and hypermedia. There are no standards for the media being transmitted, except for audio and video which coding processes are described in ISO/IEC MPEG-2 [38]. MPEG-2 also provides a means called Digital Storage Media Command Control (DSM-CC) for user interaction on video sequences restitution. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 9 User View | |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 9.1 Main categories of users | ETR 084 [7] introduces three categories of users: - the information producer is the source of the multimedia and hypermedia information accessed and interchanged within the service; - the information manager is the service operator, responsible for enabling access to the information base as well as administering information interchange between users; - the information consumer is the final user of the service, who retrieves and consults the information for its own purposes. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 9.2 Information producer requirements | The information producer is in charge of the conception of the Multimedia application. He must provide: - the different media; - the scripts linking these media. If the information producer is not the owner of the server, his main requirement may be to upload the application (media, scripts): - by off-line means (CD-ROM, ...); - by on-line means (network access). In both cases, the interchange is non real-time. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 9.3 Information manager requirements | The information manager is in charge of the server. He administers the multimedia application provided by the information producer in order to make it available to the information consumer. His main requirements are: - administration of media and scripts; - administration of users (information producers, information consumers); - upload of multimedia applications including media and scripts; - charging; - access control / protection (firewalls); - system monitoring. TR 101 170 V1.1.1 (1998-05) 49 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 9.4 Information consumer requirements | The information consumer is the end user who consults the multimedia information made available by the information manager. His main requirements are: - remote consultation (real-time downloading) of multimedia information (media, scripts); - local consultation (non real-time downloading) of multimedia information (media, scripts); - charging (service / network). Other important attributes can also be identified, which are out of the scope of the present document. For example: - cost of terminals; - cost of Metropolitan and Wide Area Networks (MAN, WAN) deployments; - Human Computer Interface (HCI). |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 10 Media view | The aim of this part of the present document is not to establish an exhaustive list of existing standards for the coding for various media. It identifies the different categories of media, builds a list of requirements for each and gives the main coding formats. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 10.1 Main categories of media | ETR 225 [6] and TCR-TR 026 [1] introduce a categorization of media: - telematic files; - graphics; - still picture; - audio; - video. In some cases, these media have particular distribution and / or processing requirements, as shown thereafter. ETR 084 [7] may also be another helpful source of information for the description of these media by building a quite exhaustive list of techniques, international standards and industry formats. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 10.2 Telematic files | Telematic files are documents including text in any type of coded form (e.g. fax, word processor document, simple ASCII, etc.). They don’t have particular processing requirements. Note that characters may be coded with 7 bits or 8 bits, depending on the ASCII coding system being used, so converters may be needed. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 10.3 Graphics | In most cases, this media is used for simple graphic presentations (e.g. charts, CAD sheets, ...). These graphics are coded with vectors, which differentiate them from still pictures. Its main processing requirements are: - high definition video cards; - high definition screens; - fast vector computing; TR 101 170 V1.1.1 (1998-05) 50 - as long as the amount of information is low, bitrate is not an important attribute. The main formats used to code graphics are: - Windows MetaFile (WMF); - Computer Graphic Metafile (CGM); - Corel Draw (CDR); - AutoDesk AutoCAD sheets (DXF). |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 10.4 Still pictures | This media is coded pixel-by-pixel and sometimes uses a compression algorithm. This algorithm can be of two types: - lossless, if high quality is required (e.g. medical images); - non-lossless (lossy), if fast access is a requirement. Still pictures main processing requirements are: - large colour palettes; - high definition video cards; - high definition screens; - bitrate, if fast access / downloading is necessary (e.g. for press agencies scanning photo catalogues); - interleave coded form, giving the ability for a system receiving the picture to display it before it is completely transmitted; - Discrete Cosine Transform (DCT) decoder for JPEG still pictures. The main formats used to code still pictures are: - Windows Device-Independent Bitmap (BMP); - CompuServe Graphics Interchange Format (GIF); - Tagged Image File Format (TIFF); - ISO/IEC JPEG [39]. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 10.5 Audio | Audio processing depends on: - quality to be produced (e.g. speech, CD-Audio quality, ...); - number of simultaneous audio tracks (mono, stereo, Dolby Surround, ...). Its main requirements (for a real-time use) are: - high bandwidth (up to 64 Kbit/s); - constant bitrate; - synchronization, when more than one audio track is transmitted. NOTE: ISO/IEC MPEG-1 [37] and MPEG-2 [38] provide an embedded synchronization within the bitstreams. TR 101 170 V1.1.1 (1998-05) 51 The main formats used to code audio are: - ITU-T Recommendation G.711 [25]; - ITU-T Recommendation G.722 [26]; - ITU-T Rececommendation G.728 [27]; - Microsoft WAVeform (WAV); - ISO/IEC MPEG-1 audio streams [37]; - ISO/IEC MPEG-2 audio streams [38]; - Musical Instruments Digital Interface (MIDI). NOTE: MIDI files does not contain any audio information. They simply contain note numbers and associated parameters such as velocity, aftertouch, which will be reproduced by an internal (audio card) or external (keyboard) synthesizer. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 10.6 Video | This media (for a real-time use) requires: - high bandwidth (up to 1,5 Mbit/s for MPEG-1, up to 40 Mbit/s for MPEG-2); - constant bitrate; - Discrete Cosine Transform (DCT) decoder; - synchronization, when more than one audio track is transmitted. NOTE: ISO/IEC MPEG-1 [37] and MPEG-2 [38] provide an embedded synchronization within the bitstreams. The main formats used to code video are: - ITU-T Recommendation H.261 [24]; - Microsoft Audio Video Interleaved (AVI); - Intel Digital Video Interactive (DVI); - ISO/IEC MPEG-1 [37]; - ISO/IEC MPEG-2 [38]. NOTE: Moving JPEG (MJPEG) is another way of coding video information by using only JPEG frames instead of intra-coded, predicted and interpolated pictures as for MPEG-1 or MPEG-2. Most of the active Multimedia working bodies have agreed that MPEG (whether it is MPEG-1, more appropriate for CD-ROM, or MPEG-2 for TV broadcast) is the major video coding standard. So it appears that Microsoft Audio Video Interleaved (AVI) and Intel Digital Video Interactive (DVI) will not be used very much. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 11 Service view | At present time, new multimedia services are still under development. For the purpose of the present document videoconferencing and corporate document handling have been considered. These services are defined by the ITU-T T.120 Series of Recommendation and the ITU-T T.190 Series of Recommendation, respectively. They both introduce the element of multipoint communications that is dealt with in ITU-T Recommendations T.122 [17] and T.125 [20]. The service view results in requirements for an (network related) transport interface between the components of a ITU-T T.120 Series conforming implementation and an application related interface, that offers MCS and GCC functionality to an application. TR 101 170 V1.1.1 (1998-05) 52 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12 Network view | Multimedia applications can be supported by many different types of network. In order to derive a hypothetical standard multimedia PCI for all possible multimedia and monomedia applications for all applicable network types, the following analysis has been carried out: - list and explanation of applications that need to be supported; - types and simple descriptions of possible networks used to support multimedia and monomedia applications presented as a table; - for each network type the following details have been presented: - detailed description of network capabilities; - typical protocol stack for an applicable multimedia application; - listing of network attributes; - listing of applicable ITU-T Recommendations, ETSI Standards and abbreviations. - standardized representation of network protocol stacks derived from all applicable network types; - recommendations for multimedia and monomedia generalised API based on network view and applicable applications. Each of the above items is considered in the subclauses below. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.1 Networks - general description | Each of the network types are reviewed in table 31 and their capabilities in the support of different data types and other information is also included. Table 31: Use of different networks in the support of multimedia Network Description PSTN Public Switched Telephone Network: This is the general telephone network with analogue local loops. Multimedia applications can be supported using modems. Different data types can be supported limited by the maximum data rate of 32 kbit/s (without compression). The PSTN with the addition of digital local loops (i.e. N-ISDN) provides better support and greater bandwidth for data applications. Design of a generalised API need not specifically take into account analogue loop PSTNs. CSPDN Circuit-Switched Public Data Network: CSPDNs are the X.21-based data networks. Multimedia applications can be supported for different data types limited by the maximum data rate of 64 kbit/s (without compression) although multiple connections can be made to achieve greater bandwidth. This type of network is being replaced by N-ISDNs and design of a generalised API need not take into account CSPDNs. PSPDN Packet-Switched Public Data Network: PSPDNs are the X.25-based networks ideally suited for file transfer applications. This type of network is not intended for the transfer of isochronous data (real-time voice and video), but can still support multimedia applications limited by the effective maximum data rate of 9,600 bit/s. Some PSPDN users are changing to Frame Relay and SMDS networks to achieve higher throughput. Design of a generalised API need not specifically take into account PSPDNs although X.25 PLP is often used at layer 3 in the support of some LAN/WAN networking applications so this layer 3 protocol must not be excluded from the API considerations. N-ISDN Integrated Services Digital Network (Narrowband - to distinguish it from the Broadband version): ISDNs are digital end-to-end networks that support 64 kbit/s channels (circuit-switched) although multiple connections can be made to achieve greater bandwidths (up to 1,920 kbit/s per primary rate access). ISDNs can also support packet data via packet handling equipment. GSM Global System for Mobile Communications: A digital mobile telephony network with a data service based on 9.6 kbit/s bandwidth. Multimedia applications can be supported for different data types limited by the maximum data rate of 9.6 kbit/s (without compression) although when the new HSCSD (High Speed Circuit Switched Data) service starts, bandwidths of 64 kbit/s, 76.8 kbit/s and 96 kbit/s can be achieved. TR 101 170 V1.1.1 (1998-05) 53 Network Description Frame Relay Although originally specified as a service of N-ISDN, Frame Relay networks now exist in their own right and are being used as the replacement for applications that would normally use packet-switched networks (both public and private). This type of network is not intended for the transfer of isochronous data, but can still support multimedia applications limited by the effective maximum data rate of 2 048 kbit/s. These networks rely upon the built-in reliability and virtually error-free performance of digital networks so the protocol stack for Frame Relay does not include the error checking and retransmission overhead normally associated with packet networks. For Frame Relay the higher layer end-to-end protocols are expected to verify the integrity of the data. The generalised API need not support applications based on Frame Relay as these networks generally only support file and text transfers. SMDS (CBDS) Switched Multimegabit Data Service (called Connectionless Broadband Data Service by ETSI): These are digital end-to-end networks operating at rates up to 140/155 Mbit/s providing a connectionless data service. Information is sent in packets (at layer 3). This type of network is not intended for the transfer of isochronous data (although some network providers claim that they are adding isochronous service to SMDS) but can still support multimedia applications. LAN Local Area Networks (e.g. Ethernet, Token Ring): These type of networks deliver applications and services to the desktop and operate at data rates up to 100 Mbit/s. Current systems do not adequately support applications involving real-time voice and video although there are some newer developments in this area. The generalised API must support applications based on LANs. ATM To The Desktop Asynchronous Transfer Mode: ATM is starting to be used with LANs as a high-bandwidth switch and this is delivering many applications to the desktop. Work in this area is being addressed by the ATM Forum and the generalised API must address this area. Public ATM (B-ISDN) Broadband ISDN: This type of network supports everything that any of the other networks support and can carry information at up to 622 Mbit/s. All types of multimedia applications can be supported (including video- on-demand). Work in this area is being addressed by the ATM Forum/ITU-T but it is probably five to eight years before a full public service will be available. Specification of the generalised API should take into account the current work being undertaken by the ATM Forum/ITU-T. Cable TV This type of network was primarily intended to provide broadcast TV to homes. Using the latest technology and delivery systems, many different types of multimedia applications can be supported. These networks will have similar capabilities to B-ISDN with the main difference being the emphasis on services (i.e. TV distribution is the first consideration for Cable TV networks whereas communication is the first consideration for B-ISDNs) and the distribution. Cable TV networks are traditionally "tree and branch" networks, whereas public telephone networks (from which B-ISDN can be considered to have evolved from) usually employ a policy of individual local loops per subscriber, although this may change. Note that Cable TV is not to be confused with CATV (Community Antenna TV) which is a TV antenna/aerial distribution system. The generalised API must support applications based on Cable TV systems. Now the support for the identified applications are considered for each of the networks mentioned above. Table 32 gives a general overview of the capabilities of the network in handling various applications. Each of these network types are now examined in greater detail and examples are given of how each network type can support multimedia applications. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.2 Networks - detailed description | The following network types are considered in detail: • PSTN; • CSPDN; • PSPDN; • N-ISDN; • GSM; • Frame Relay; • SMDS (CBDS); • LAN; • ATM To The Desktop; • Public ATM (B-ISDN); • Cable TV. TR 101 170 V1.1.1 (1998-05) 54 Table 32: Network support for various applications Service Data Rate [Mbit/s] Typical Application PSTN with Modem CSPDN X.21 or X.21bis PSPDN X.25 GSM ISDN Frame Relay SMDS LANs B-ISDN with ATM Cable TV Database up to 2 Text & Simple Graphics Some Some Some Some Some All All All All All Access 2 - 10 Graphics -- -- -- -- -- Some All Some All All over 10 Medical Images, CAD files -- -- -- -- -- -- Some Some All All File up to 2 Text, PC comms Some Some Some Some Some All All All All All Transfer 2 - 10 Graphics, Main Frame comms -- -- -- -- -- Some All Some All All over 10 Meteorology, Supercomputers -- -- -- -- -- -- Some Some All All LAN up to 2 4 Mbit/s Token Ring -- Some Some -- -- All All -- All All Interconnect 2 - 10 Ethernet, 16 Mbit/s Token Ring -- -- -- -- -- Some All -- All All over 10 FDDI, 100 Mbit/s LANs -- -- -- -- -- -- Some -- All All Still Image up to 2 Monochrome Some Some Some Some Some All All All All All Communication 2 - 10 Colour -- -- -- -- -- Some All Some All All over 10 High resolution e.g. CAD/CAM -- -- -- -- -- -- Some Some All All Video & PC up to 2 Talking heads Some Some -- Some Some -- Some Some All All Conferencing 2 - 10 Small screen high quality -- -- -- -- -- -- Some -- All All over 10 Large screen high quality -- -- -- -- -- -- Some -- All All Multimedia up to 2 Combinations of the above -- Some -- Some Some -- Some Some All All Networking 2 - 10 Combinations of the above -- -- -- -- -- -- Some -- All All over 10 Combinations of the above -- -- -- -- -- -- Some -- All All TR 101 170 V1.1.1 (1998-05) 55 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.2.1 PSTN | The PSTN is a circuit-switched network ideally suited for isochronous communications, such as: - full-duplex voice communications (3,1 kHz telephony); - full-duplex data communication (including still image and video) using modems. Although the core of the PSTN (i.e. the IDN) is digital, the PSTN is regarded as an analogue network due to its analogue local loops. Voice is PCM encoded in order to be transported across the IDN. Data transmission is possible by modulating all binary information into audible signals in the telephony voice frequency range (300 to 3 400 Hz) and it is then PCM encoded in a similar manner to voice for transportation across the IDN. These modulated binary signals are then demodulated in order to recover the binary information. For multimedia applications, the PSTN can still be used although there is a finite limit of the data bandwidth that can be achieved for full-duplex communication. The upper limit for modems is regarded as being in the order of 32 kbit/s. Using data and video compression techniques effective bandwidths of up to 500 kbit/s can be achieved. The PSTN can support multimedia services, such as multipoint communication service for audiographics and audiovisual conferencing. The protocol stack for this multimedia service supported by a PSTN, is shown in figure 10. Transport ITU-T X.224 Class 0 Network Null + SCF Data Link ITU-T Q.922 Physical ITU-T V.14 e.g. ITU-T V.34 Figure 10: PSTN protocol stack - ITU-T Q.922 [83]: ISDN data link layer specification for frame mode bearer services; - ITU-T V.14 [84]: Transmission of start-stop characters over synchronous bearer channels; - ITU-T V.34 [85]: Modem operating at data signalling rate of 28 800 bit/s; - ITU-T X.224 [49]: Protocol for providing the OSI connection-mode transport services; - SCF: Synchronization and Convergence Function. The network has the following service attributes: TR 101 170 V1.1.1 (1998-05) 56 Table 33: Service attributes of PSTN Attribute Value information transfer mode • circuit switched information transfer rate • up to 32 kbit/s using modem information transfer capability • unrestricted digital information (with modem) • speech • audio (3,1 kHz) • video (slow-scan, poor-quality - with modem) establishment of connection • demand • semi-permanent • permanent symmetry • symmetrical (except using certain modems - asymmetrical) type of user information • speech • sound • text • facsimile • videotex • video synchronous/asynchronous • for data using modem - synchronous and asynchronous structure • for data - modem dependant UNIs • 2-wire analogue local loop call set-up protocols • Loop dialling, or • DTMF TR 101 170 V1.1.1 (1998-05) 57 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.2.2 CSPDN | The CSPDN is a 64 kbit/s circuit-switched network intended for full-duplex digital data transmission. The CSPDN can support multimedia services, such as multipoint communication service for audiographics and audiovisual conferencing. The protocol stack for this multimedia service supported by a CSPDN, is shown in figure 11. Transport ITU-T X.224 Class 0 Network Null + SCF Data Link ITU-T Q.922 Physical ITU-T H.221 MLP ITU-T X.21 or X.21bis Figure 11: CSPDN protocol stack - ITU-T H.221 [70]: Frame structure for a 64 to 1 920 kbit/s channel in audiovisual teleservices; - ITU-T Q.922 [83]: ISDN data link layer specification for frame mode bearer services; - ITU-T X.21 [86]: Interface between data terminal equipment and data circuit-terminating equipment for synchronous operation on public data networks; - ITU-T X.21bis [87]: Use on public data networks of data terminal equipment which is designed for interfacing to synchronous V-series modems; - ITU-T X.224 [49]: Protocol for providing the OSI connection-mode transport services; - SCF: Synchronization and Convergence Function. The service attributes are shown in table 34. Table 34: Service attributes of CSPDN Attribute Value information transfer mode • circuit switched information transfer rate • 64 kbit/s information transfer capability • unrestricted digital information establishment of connection • demand • semi-permanent • permanent symmetry • symmetrical type of user information • speech • sound • text • facsimile • videotex • video synchronous/asynchronous • synchronous structure • 8 kbit/s UNIs • 4-wire digital call set-up protocols • ITU-T X.21 (or X.21bis) TR 101 170 V1.1.1 (1998-05) 58 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.2.3 PSPDN | The PSPDN is a packet-switched network intended for full-duplex digital data transmission. PSPDN generally cannot support real-time isochronous data applications (i.e. telephony and videoconferencing). However, there is a protocol stack defined for PSPDNs in the support of the multipoint communication service for audiographics and audiovisual conferencing. It is quite likely that the response times for this service will be unacceptable. The protocol stack for this multimedia service is shown in figure 12. Transport ITU-T X.224 Class 0 Network ITU-T X.25 Data Link ITU-T X.25 Physical ITU-T X.21 or X.21bis Figure 12: PSPDN protocol stack - ITU-T X.21 [86]: Interface between data terminal equipment and data circuit-terminating equipment for synchronous operation on public data networks; - ITU-T X.21bis [87]: Use on public data networks of data terminal equipment which is designed for interfacing to synchronous V-series modems; - ITU-T X.25 [88]: Interface between data terminal equipment and data circuit-terminating equipment for terminals operating in the packet mode and connected to public data networks by dedicated circuit; - ITU-T X.224 [49]: Protocol for providing the OSI connection-mode transport services. Table 35: Service attributes of PSPDN Attribute Value information transfer mode • packet switched information transfer rate • 2 400 bit/s, 4 800 bit/s and 48 000 bit/s information transfer capability • data establishment of connection • demand • semi-permanent • permanent symmetry • symmetrical type of user information • text • binary data synchronous/asynchronous • direct network connection is synchronous, via PAD either is possible structure • PDU UNIs • 4-wire digital or via PAD over 2-wire analogue using X.28 call set-up protocols • Layer 1 - ITU-T X.21 or X.21bis • Layer 2 - ITU-T X.25 • Layer 3 - ITU-T X.25 PLP TR 101 170 V1.1.1 (1998-05) 59 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.2.4 ISDN | The ISDN is a circuit-switched digital network ideally suited for isochronous communications, such as: - full-duplex voice communications (using PCM encoded 3,1 kHz speech); - full-duplex data communication (including still image and video). The ISDN can also be used for packet data communication using either an internal or external packet handling function. ITU-T Recommendation X.31 [91] gives all the relevant details. The ISDN can support multimedia services, such as multipoint communication service for audiographics and audiovisual conferencing. The protocol stack for this multimedia service supported by a ISDN, is shown in figure 13. Transport ITU-T X.224 Class 0 Network Null + SCF Data Link ITU-T Q.922 Physical ITU-T H.221 MLP ITU-T I.430 or I.431 Figure 13: ISDN protocol stack - ITU-T H.221 [70]: Frame structure for a 64 to 1 920 kbit/s channel in audiovisual teleservices; - ITU-T I.430 [89]: Basic user-network interface - Layer 1 specification; - ITU-T I.431 [90]: Primary rate user-network interface - Layer 1 specification; - ITU-T Q.922 [83]: ISDN data link layer specification for frame mode bearer services; - ITU-T X.31 [91]: Support of packet mode terminal equipment by an ISDN; - ITU-T X.224 [49]: Protocol for providing the OSI connection-mode transport services; - SCF: Synchronization and Convergence Function. TR 101 170 V1.1.1 (1998-05) 60 Table 36: Service attributes of ISDN Attribute Value information transfer mode • circuit switched (B-channel) • packet switched (B-channel and/or D-channel) information transfer rate • circuit-mode transfer - 64 kbit/s (384 kbit/s, 1 536 kbit/s and 1 920 kbit/s possible in some networks) • packet mode transfer - packets per second t.b.d. information transfer capability • unrestricted digital information • speech • audio (3,1 kHz or 7 kHz) • video establishment of connection • demand • semi-permanent • permanent symmetry • symmetrical type of user information • speech • sound • text • facsimile • videotex • video synchronous/asynchronous • synchronous structure • 8 kbit/s UNIs • Basic Access (2B+D) • Primary Rate Access (30B+D) call set-up protocols • Layer 1 - ITU-T I.430/I.431 • Layer 2 - ITU-T Q.920/Q.921 • Layer 3 - ITU-T Q.930/Q.931 TR 101 170 V1.1.1 (1998-05) 61 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.2.5 GSM | GSM is a circuit-switched digital voice network with a data communication service GSM can support multimedia services, such as multipoint communication service for audiographics and audiovisual conferencing. The protocol stack for this multimedia service supported by GSM, is depicted in figure 14. Transport ITU-T X.224 Class 0 Network Null + SCF Data Link GSM 07 Series Physical GSM 05 Series Figure 14: GSM protocol stack - GSM 05 Series [103]: Physical Layer on the Radio Path; - GSM 07 Series [104]: Terminal Adaptation Functions for MSs; - ITU-T X.224 [49]: Protocol for providing the OSI connection-mode transport services; - SCF: Synchronization and Convergence Function. Table 37: Service attributes of GSM Attribute Value information transfer mode • circuit-switched information transfer rate • 6,5 kbit/s or 13 kbit/s information transfer capability • unrestricted digital information • speech • audio (3,1 kHz or 7 kHz) • video establishment of connection • demand symmetry • symmetrical type of user information • speech • sound • text • facsimile • videotex • video synchronous/asynchronous • synchronous structure • 4 kbit/s, 8 kbit/s or PDU UNIs • GSM Air Interface call set-up protocols • Layer 1 - ETSI GSM 05 series specifications • Layer 2 - ETSI GSM 04.06 specification • Layer 3 - ETSI GSM 04.08 specification TR 101 170 V1.1.1 (1998-05) 62 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.2.6 Frame Relay | Frame Relay is a packet-switched digital network ideally suited for data communications. These networks are not to be confused with the ETSI and ITU-T specified Frame Relaying services that are supported by ISDNs. Frame Relay can support multimedia services, such as multipoint communication service for audiographics and audiovisual conferencing. The protocol stack for this multimedia service supported by Frame Relay, is depicted by figure 15. Transport ITU-T X.224 Class 0 Network Null + SCF Data Link ITU-T I.365 / X.36 Physical ITU-T G.703, X.21 or X.21bis Figure 15: Frame Relay protocol stack - ITU-T G.703 [97]: Physical/electrical characteristics of hierarchical digital interfaces; - ITU-T I.365 [98]: Frame relaying services specific convergence sublayer; - ITU-T X.21 [86]: Interface between data terminal equipment and data circuit-terminating equipment for synchronous operation on public data networks; - ITU-T X.21bis [87]: Use on public data networks of data terminal equipment which is designed for interfacing to synchronous V-series modems; - ITU-T X.36 [99]: Interface between DTE and DCE for public data networks providing frame relay datatransmission service by dedicated circuit; - ITU-T X.224 [49]: Protocol for providing the OSI connection-mode transport services; - SCF: Synchronization and Convergence Function. Table 38: Service attributes of Frame Relay Attribute Value information transfer mode • frame relaying/PDU information transfer rate • from 64 kbit/s to 2 048 kbit/s (typical values) information transfer capability • data establishment of connection • demand • permanent symmetry • bi-directional symmetric type of user information • text • binary data synchronous/asynchronous • synchronous structure • service data unit integrity UNIs • can be wire, coax or fibre call set-up protocols • ITU-T I.365/X.36 TR 101 170 V1.1.1 (1998-05) 63 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.2.7 SMDS (CBDS in ETSI) | SMDS is a circuit-switched digital network SMDS can support multimedia services, such as multipoint communication service for audiographics and audiovisual conferencing. The protocol stack for this multimedia service supported by SMDS, is shown in figure 16. Transport ITU-T X.224 Class 0 Network Null + SCF Data Link ETS 300 217 Physical ITU-T G.703 (and others) Figure 16: SMDS protocol stack - ITU-T G.703 [97]: Physical/electrical characteristics of hierarchical digital interfaces; - ETS 300 217 [102]: Connectionless Broadband Data Service (CBDS); - ITU-T X.224 [49]: Protocol for providing the OSI connection-mode transport service; - SCF: Synchronization and Convergence Function. Table 39: Service attributes of SMDS Attribute Value information transfer mode cell information transfer rate up to 155 Mbit/s information transfer capability • unrestricted digital information • video (isochronous SMDS only) establishment of connection • demand • semi-permanent • permanent symmetry • symmetrical type of user information • text synchronous/asynchronous • synchronous structure • cell UNIs • ITU-T G.703 and others call set-up protocols • ETSI 300 217 specification TR 101 170 V1.1.1 (1998-05) 64 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.2.8 LANs | LANs are a connectionless digital local network ideally suited for datacommunications. LANs can support multimedia services but primarily are used in the support of monomedia services. The protocol stack for these service are depicted in figure 17. Transport ITU-T X.224 Class 0 Network Null + SCF Data Link IEEE 802.2 LLC IEEE 802.X MAC Layer Physical IEEE 802.3 or 802.4 Figure 17: LAN protocol stack - IEEE 802.2: Logical Link Control (LLC); - IEEE 802.3: Ethernet; - IEEE 802.4: Token Ring; - ITU-T X.224 [49]: Protocol for providing the OSI connection-mode transport services; - SCF: Synchronization and Convergence Function. Table 40: Service attributes of LANs Attribute Value information transfer mode • connectionless information transfer rate • variable depending on loading information transfer capability • unrestricted digital information establishment of connection • demand symmetry • symmetrical type of user information • text • facsimile • videotex synchronous/asynchronous • synchronous structure • LAN messages (IEEE 802) UNIs • Media Access Units (IEEE 802) call set-up protocols • IEEE 802 series TR 101 170 V1.1.1 (1998-05) 65 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 12.2.9 ATM to the desktop and B-ISDN | ATM is a connection-oriented and connectionless digital network ideally suited for isochronous communications, such as: - full-duplex voice communications (using PCM encoded 3,1 kHz speech); - full-duplex data communication (including still image and video). ATM can support multimedia services, such as multipoint communication service for audiographics and audiovisual conferencing. The protocol stack for this multimedia service supported by ATM, is shown in. B-ISDN is a connection-oriented and connectionless digital network ideally suited for isochronous communications, such as: - full-duplex voice communications (using PCM encoded 3,1 kHz speech); - full-duplex data communication (including still image and video). B-ISDN can support multimedia services, such as multipoint communication service for audiographics and audiovisual conferencing. The protocol stack for this multimedia service supported by B-ISDN, is also depicted in figure 14. Transport ITU-T X.224 Class 0 Network Null + SCF Data Link ITU-T I.363 ITU-T I.361 Physical ITU-T Q.2000 Series Figure 18: ATM protocol stack - ITU-T Q.2000 Series: Broadband ISDN; - ITU-T I.361 [100]: B-ISDN ATM layer specification; - ITU-T I.363 [101]: B-ISDN ATM adaption layer specification; - ITU-T X.224 [49]: Protocol for providing the OSI connection-mode transport services; - SCF: Synchronization and Convergence Function. TR 101 170 V1.1.1 (1998-05) 66 Table 41: Service attributes of ATM Attribute Value information transfer mode • circuit switched • packet switched and connectionless information transfer rate • circuit-mode transfer • packet mode transfer information transfer capability • unrestricted digital information • speech • audio (3,1 kHz, 7 kHz or 15 kHz) • video establishment of connection • demand • semi-permanent • permanent symmetry • symmetrical and asymetrical type of user information • speech • sound • text • facsimile • videotex • video • TV synchronous/asynchronous • synchronous and/or asynchronous structure • cell UNIs • ITU-T Q.2000 series call set-up protocols • Layer 1 - ITU-T Q.2000 series • Layer 2 - ITU-T Q.2921 • Layer 3 - ITU-T Q.2931 TR 101 170 V1.1.1 (1998-05) 67 12.2.10 Cable TV A Cable TV network is: - full-duplex voice communications (using PCM encoded 3,1 kHz speech); - full-duplex data communication (including still image and video). A cable TV network can support multimedia services, such as multipoint communication service for audiographics and audiovisual conferencing. The protocol stack for this multimedia service supported by a ISDN, is shown in figure 19. Transport ITU-T X.224 Class 0 Network Null + SCF Data Link proprietary Physical ADSL or VDSL Figure 19: Cable TV network protocol stack - ITU-T X.224 [49]: Protocol for providing the OSI connection-mode transport services; - SCF: Synchronization and Convergence Function. Table 42: Service attributes of Cable-TV networks Attribute Value information transfer mode • varies information transfer rate • varies information transfer capability • unrestricted digital information • speech • audio (3,1 kHz, 7 kHz or 15 kHz) • video establishment of connection • demand • semi-permanent • permanent symmetry • symmetrical type of user information • speech • sound • text • facsimile • videotex • video • TV synchronous/asynchronous • synchronous structure • varies UNIs • Cable TV (wire, coax or fibre) call set-up protocols • not standardized TR 101 170 V1.1.1 (1998-05) 68 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 13 List of demands of multimedia environments | The present document tries to filter out the demands and issues imposed by the different categories of multimedia applications, users, media, services and networks in order to come to a list of requirements the generic PCI shall provide. |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 13.1 Demands of multimedia application classes | The requirements for PCIs depend on: - information interchange type (real-time or non real-time, as introduced in ETR 084 [7]); - security; - connectability; - independence from network aspects; - connection types. Table 43 gives the requirements list: Table 43: Requirements list for demands of multimedia application classes Real-time information interchange Non real-time information interchange Security Connectability Independence from network aspects Connection types • Demand of bandwidth • Dynamic allocation of bandwidth • Demand of synchronization • Demand of flow control • Transparent exchange of objects • Multiplex capabilities • Transparent data compression • Demand of bandwidth • Dynamic allocation of bandwidth • Demand of flow control • Multiplex capabilities • Transparent data compression • Authentication • Signature • Partial encryption • Charging information (network) • Charging information (service provider) • Optional codec capabilities • Connectability to external devices (handset, VCR, smart card reader, etc.) • Operating System independence • Ability to be easily extended • Connectability on demand • Transparent connect and disconnect • Transparent addressing capability • Symmetric / asymmetric interactivity considerations • Point-to-point and point-to- multipoint capabilities • Capability to act as the starting or the ending point of a connection TR 101 170 V1.1.1 (1998-05) 69 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 13.2 Demands of users | The requirements for PCIs depend on: - information interchange type (real-time or non real-time, as introduced in ETR 084 [7]); - security; - connection types. Table 44 gives the requirements list: Table 44: Requirements list for demands of users Real-time information interchange Non real-time information interchange Security Connection types • Demand of bandwidth • Dynamic allocation of bandwidth • Demand of synchronization • Transparent exchange of objects • Demand of bandwidth • Dynamic allocation of bandwidth • Authentication • Signature • Partial encryption • Charging information (network) • Charging information (service provider) • Symmetric / asymmetric interactivity considerations • Point-to-point and point-to- multipoint capabilities • Capability to act as the starting or the ending point of a connection |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 13.3 Demands of media | The requirements for PCIs depend on: - information interchange type (real-time or non real-time, as introduced in ETR 084 [7]); - connectability; - independence from network aspects. Table 45 gives the requirements list: Table 45: Requirements list for demands of media Real-time information interchange Non real-time information interchange Connectability Independence from network aspects • Demand of bandwidth • Dynamic allocation of bandwidth • Demand of synchronization • Demand of flow control • Transparent exchange of objects • Multiplex capabilities • Transparent data compression • Demand of bandwidth • Dynamic allocation of bandwidth • Demand of flow control • Multiplex capabilities • Transparent data compression • Optional codec capabilities • Connectability to external devices (handset, VCR, smart card reader, etc.) • Transparent data compression |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 13.4 Demands of services | Only videoconferencing and corporate document handling services have been considered. The demands derived result in: - provision of ITU-T Recommendation T.122 (MCS) conforming functionality; - provision of ITU-T Recommendation T.124 (GCC) conforming functionality; - provision of ITU-T Recommendation X.214 conforming primitives. TR 101 170 V1.1.1 (1998-05) 70 |
21bc628148fd0ff0ade3938bbe5b8f90 | 101 170 | 13.5 Demands of network | The following network protocol stacks need to be considered when designing standardized PCIs: • N-ISDN; • GSM; • SMDS (CBDS); • LANs; • ATM to the desktop; • public ATM (B-ISDN); • Cable TV. In addition the use of X.25 PLP at layer 3 has to be taken into account. N-ISDN uses a separate channel in which to set up a call. For N-ISDN applications that require multiple links and/or channel aggregation (e.g. videoconferencing), control of call set-ups is also needed by the application through the PCI. TR 101 170 V1.1.1 (1998-05) 71 Annex A: Glossary ADSL: Asymmetrical Digital Subscriber Line. ADSL is an enhanced system developed for high bitrate transmission on twisted pair copper cables. B-ISDN: Broadband ISDN. This type of network supports everything that any of the other networks support and can carry information at up to 622 Mbit/s. Cable TV: This type of network was primarily intended to provide broadcast TV to homes. Not to be confused with CATV. CATV: Community Antenna TV, which is a TV antenna/aerial distribution system. CSPDN: Circuit-Switched Public Data Network. CSPDNs are the X.21-based data networks. Frame Relay: Although originally specified as a service of N-ISDN, Frame Relay networks now exist in their own right and are being used as the replacement for applications that would normally use packet-switched networks (both public and private). GSM: Global System for Mobile communications. A digital mobile telephony network with a data service based (for the time being) on 9,6 kbit/s bandwidth. LAN: Local Area Network. This type of network deliver applications and services to the desktop and operate at data rates up to 100 Mbit/s. N-ISDN: Integrated Services Digital Network; Narrowband - to distinguish it from the Broadband version. PSPDN: Packet-Switched Public Data Network. PSPDNs are the X.25-based networks. PSTN: Public Switched Telephone Network. This is the general telephone network with analogue local loops, also known as Plain Old Telephone Service (POTS). SMDS: Switched Multimegabit Data Service; CBDS (Connectionless Broadband Data Service) in ETSI. These are digital end- to-end networks operating at rates up to 140/155 Mbit/s providing a connectionless data service. Information is sent in packets (at layer 3). TR 101 170 V1.1.1 (1998-05) 72 Annex B: Bibliography The following material, though not specifically referenced in the body of the present document, gives supporting information. 1) ETS 300 080 (1992): "Integrated Services Digital Network (ISDN); ISDN lower layer protocols for telematic terminals". 2) ETS 300 243-2 (1995): "Terminal Equipment (TE); Programmable Communication Interface (PCI) APPLI/COM for facsimile group 3, facsimile group 4, teletex and telex services Part 2: Conformance testing". 3) ISO/IEC DIS 10744 (1991): "Information technology - Hypermedia/time-based structuring language (Hytime)". 4) ISO/IEC DISP 12063-n: "MHS -Electronic Data Interchange Messaging". 5) ISO/IEC ISP 10611-n: "MHS - Common messaging". 6) ISO/IEC ISP 12062-n: "MHS - Interpersonal Messaging". 7) ITU-T Recommendation F.400 (1992): "MHS System and Service overview". 8) ITU-T Recommendation F.401 (1992): "MHS Naming & Addressing for Public MH Services". 9) ITU-T Recommendation F.410 (1992): "MHS The Public Message Transfer Service". 10) ITU-T Recommendation F.415 (1988): "MHS Intercommunication with Public Physical Delivery Services". 11) ITU-T Recommendation F.420 (1992): "MHS The Public IPM Service". 12) ITU-T Recommendation F.421 (1988): "MHS Intercommunication Between IPM Service and Telex". 13) ITU-T Recommendation F.422 (1988): "MHS Intercommunication Between IPM Service and Teletex". 14) ITU-T Recommendation Q.921 (1992): "ISDN user-network interface - Data link layer specification". 15) ITU-T Recommendation T.30 (1988): "Procedures for document facsimile transmission in the general switched telephone network". 16) ITU-T Recommendation T.90 (1992): "Characteristics and protocols for telematic services in ISDN". 17) ITU-T Draft Recommendation T.170: "Audio-visual interactive (AVI) systems". 18) ITU-T Draft Recommendation T.171: "Coded representation of Multimedia / Hypermedia information objects". 19) ITU-T Draft Recommendation T.175: "Protocols for browsing, downloading and executing AVI applications". 20) ITU-T Draft Recommendation T.176: "Protocols for synchronization of executed AVI applications". 21) ITU-T Recommendation X.200 (1988): "ISO 7498, Information processing systems - Open Systems Interconnection - Basic Reference Model (1984)". 22) ITU-T Recommendation X.402 (1992): "MHS Overall Architecture". 23) ITU-T Recommendation X.403 (1988): "Conformance testing". 24) ITU-T Recommendation X.407 (1998): "MHS Abstract Service Definition". 25) ITU-T Recommendation X.408 (1988): "MHS Encoded Information Type Conversion Rules". 26) ITU-T Recommendation X.411 (1992): "MHS MTS Abstract Service Definition and Procedures". 27) ITU-T Recommendation X.413 (1995): "MHS MS Abstract Service Definition". TR 101 170 V1.1.1 (1998-05) 73 28) ITU-T Recommendation X.419 (1992): "MHS Protocol Specifications". 29) ITU-T Recommendation X.420 (1992): "MHS Interpersonal Messaging System (IPM)". 30) ITU-T Recommendation X.435 (1991): "MHS Electronic Data Interchange Messaging System". 31) ITU-T Recommendation X.440 (1992): "MHS Voice Messaging System". 32) RFC 768 (1980): "User Datagram Protocol". 33) RFC 791 (1981): "Internet Protocol". 34) RFC 906 (1984): "TFTP". 35) ITU-T Recommendation H.233 (1993): "Confidentiality systems for audiovisual services". 36) ITU-T Recommendation H.242 (1993): "System for establishing communication between audiovisual terminals using digital channels up to 2 Mbit/s". 37) ITU-T Recommendation H.230 (1993): "Frame-synchronous control and indication signals for audiovisual systems". 38) ITU-T Recommendation Q.939 (1993): "Digital subscriber signalling system No. 1 (DSS 1) - Typical DSS 1 service indicator codings for ISDN telecommunications services". 39) ITU-T Recommendation I.420 (1988): "Basic user-network interface". 40) ITU-T Recommendation H.231 (1993): "Multipoint control units for audiovisual systems using digital channels up to 2 Mbit/s". 41) ITU-T Recommendation H.243 (1993): "Procedures for establishing communications between three or more audiovisual terminals using digital channels up to 2 Mbit/s". 42) RFC 1167 (1990): "Simple Network Management Protocol (1990) - replaces RFC 1098". 43) RFC 1213 (1991): "Management Information Base (1991) - replaces RFC 1158". 44) RFC 1483 (1993): "Multiprotocol Encapsulation over ATM Adaptation Layer 5". 45) Draft ITU-T Recommendation F.MDS (1994): "Multimedia distribution services baseline document". 46) ETR 228 (1995): "Terminal Equipment (TE); Broadband Multimedia Information Retrieval Service". 47) ETR 176 (1995): "Terminal Equipment (TE); Interworking and interoperability of retrieval services and audiovisual services on narrow band networks". 48) ISO/IEC CD 14478-1 (1994): "Presentation Environments for Multimedia Objects (PREMO)". TR 101 170 V1.1.1 (1998-05) 74 History Document history V1.1.1 May 1998 Publication ISBN 2-7437-2163-4 Dépôt légal : Mai 1998 |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 1 Scope | The present document describes the requirements for TIPHON Transport Plane capabilities as identified in [1]. |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 2 References | For the purposes of this Technical Report (TR) the following references apply: [1] ETSI TR 101 877: "Telecommunications and Internet Protocol Requirements Definition Study; Scope and Requirements for a Simple call". [2] ETSI TR 101 835: "Telecommunications and Internet Protocol Harmonization over Networks (TIPHON); Project method definition". [3] ETSI TS 101 329-4: "Telecommunications and Internet protocol Harmonization Over Networks (TIPHON) Release 4; Functional Entities, Reference Points and Information Flows Definition; Part 4: Quality of Service Management". [4] ITU-T Recommendation Y.1310: "Transport of IP over ATM in public networks". |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 3 Definitions and abbreviations | |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 3.1 Definitions | For the purposes of the present document, the following terms and definitions apply: administrative domain: bounded entity within which all encompassed constituent elements are under common ownership, operation and management domain: result of the application of specific policies to a specific network technology signalling entity: element capable of sending signalling information For instance terminal, router, service element. transport domain: implementation of the transport plane functionality Transport Abstraction Layer: provides a set of domain independent capabilities derived from the underlying Network Abstraction Layer in response to the transport and connectivity requirements of the Service Abstraction Layer |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: IP Internet Protocol MLPS Multi Protocol Label Switching QoS Quality of Service SCTP Secure TRansport Control Protocol SLA Service Level Agreement TCP Transport Control Protocol UDP User Datagram Protocol ETSI ETSI TR 101 311 V1.1.1 (2001-06) 6 |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 4 Introduction to the TIPHON transport plane | The TIPHON environment addresses the case where multiple networks, possibly employing differing network technologies, inter-work to provide end-to-end communications services as shown in figure 1. This model supports the different business roles found within the heterogeneous communications environment envisaged by TIPHON (see annex A of [1]) and commonly found in modern public communications networks. Network Abstraction Layer Transport Abstraction Layer Service Abstraction Layer Terminal Domain #1 Terminal Domain #2 Access Domain#1 Transit Domain#1 Access Domain#2 Transit Domain#2 Service Application Layer TIPHON Application Plane TIPHON Transport Plane Transport Plane/Application Plane Interface Figure 1: The TIPHON network and service environment model. The TIPHON network and service environment model is separated into two planes that exist across the various network domains encountered in the end-to-end communications path. These two planes connect with a Management Plane, shown in figure 2, which exists outside of the TIPHON network and service environment. Transport plane TIPHON Transport SCN Plane TIPHON Application Plane Figure 2: TIPHON planes ETSI ETSI TR 101 311 V1.1.1 (2001-06) 7 As shown, the upper plane comprises the Service Application and Service Abstraction Layers and is termed the TIPHON Application Plane. This plane addresses the implementation of end-to-end communications applications. The lower plane includes the Transport and Network Abstraction Layers and is termed the TIPHON Transport Plane. The TIPHON Transport Plane provides domain independent communications capabilities to the TIPHON Application Plane. Requirements placed upon the TIPHON Transport Plane by the TIPHON Application Plane are expressed in Service Independent Requirements documents in accordance with the TIPHON project method [2]. The present document describes sets of Service Independent Requirements that specify the required behaviour of the TIPHON Transport Plane. The TIPHON Application Plane is expressed in terms of Service Applications and Service Capabilities that are described elsewhere. |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 4.1 Functionality in the transport plane | The TIPHON transport plane supports the TIPHON Application Plane by providing transport for signalling and media streams to multiple applications. Each type of stream has its own requirements on the transport capabilities provided by the TIPHON Transport Plane. The TIPHON Transport Plane provides generic transport functionality and hence includes protocol layers up to and including ISO Layer 4. For IP-based transport this includes protocols such as TCP, UDP and SCTP. This means that functionality such as security is also within the scope of the TIPHON Transport Plane. The Transport Plane contains the functionality that is necessary for its own performance, like QoS and routing protocols. 4.2 Assumed business models The TIPHON telephony application is intended for commercial deployment. The functionality in the transport plane service capability shall support the business requirements of the operators of the network equipment to meet their business and regulatory constraints. A TIPHON Transport Domain: • may allow non-TIPHON data applications to share the same transport infrastructure; • should provide a Quality of Service capability independently of the application requesting it; • may serve multiple TIPHON application domains. Application Domain Transport Domain 1 Transport Domain 2 Application Domain End-user/ Enterprise Domain U-T A-T T-T U-A Figure 3: Transport Plane context There are three kinds of users of the transport plane functionality, each of those impose differing requirements as follows: • end-users & enterprises: will require communication with application domains to access the applications and transport domains to get the bandwidth they need; • application domains: will need to communicate with users and enterprises, other application domains and transport domains to signal for their service and to establish bandwidth for signalling and media; ETSI ETSI TR 101 311 V1.1.1 (2001-06) 8 • other transport domains: need to establish bandwidth for signalling and media. See also annex A of [1] for an analysis of the possible relationships between roles and hence domains. |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 5 Requirements | |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 5.1 Transport Capabilities | The TIPHON transport plane provides functionality for 3 generic transport capabilities: • best effort packet transport (reliable and unreliable); • QoS-enabled packet transport for the media; • QoS-enabled packet transport for the signalling. |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 5.2 Deployment specific policies | Transport domains are free to choose the way in which they provide functionality. The operator of a transport domain may choose local policies and technologies provided they fulfil the overall requirements. The TIPHON transport plane shall provide the means to support such local policies. Examples of these local policies are: • QoS mechanisms (There is a choice of QoS mechanisms such as static over provisioning, IntServ, DiffServ, MPLS etc which may be use on their own or in combination); • addressing mechanisms (for example private addressing ranges or globally unique addresses; • access control; • admission control; • transport mechanisms (IP version 4, IP version 6, or something else…); • policing mechanisms (such as policy enforcement, e.g. discard policy). |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 5.3 Core requirements | 1) The transport plane shall allow for appropriate entities to communicate for the purposes of signalling and media streams. 2) The Transport Abstraction Layer shall provide an abstraction from underlying transport network technologies and differences in policy between multiple domains. The TIPHON Transport Plane might be aware of the fact that the underlying transport mechanism is a wireless link, in that case the TIPHON Transport Plane shall hide terminal mobility from the telephony application as long as agreed communication is possible with the terminal (i.e. it stays within range). 3) There shall be no assumption that Transport Addresses are globally unique although they must be unique within the same domain. 4) A signalling transport shall provide a means of uniquely identifying the originating and terminating signalling entity (e.g. terminal, service node etc.). 5) The transport plane shall be able to provide a unique terminal ID to support access control, legal intercept and lifeline services. ETSI ETSI TR 101 311 V1.1.1 (2001-06) 9 6) The transport plane shall provide a reference point enabling the physical location of terminals (fixed and mobile), to support location aware services as well as lifeline/emergency calling service and legal interception requirements. 7) The transport plane shall allow multiple signalling interfaces terminating on a signalling entity. |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 5.4 Transport Quality | 1) Transport domains shall accept, in real-time, request for flows with or without QoS control from application domains and from other transport networks. 2) The purpose of the TIPHON Transport Abstraction Layer includes mapping from transport independent QoS descriptions to transport dependent QoS descriptions. 3) Reservations (static or dynamic) may be per: • end-point (host); • end-point and port; • end-point and subdivisions e.g. per set of ports; • pair of end-points (hosts); • pair of end-points and pair of ports; • pair of endpoints and pair of sets of ports. 5) The transport plane network shall support signalling traffic with adequate low delays and reliability. 6) The transport shall be able to identify signalling units received containing errors. 7) The transport shall provide a means to detect signalling congestion on the route and if possible to notify the application using this transport service. |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 5.5 Media Quality of Service | The telephony application has the following media requirements: 1) Quantitative guarantees: The transport plane shall facilitate guaranteed (on a statistical basis) end-to-end bandwidth capacity with appropriately bounded delay, loss and jitter. 2) Monitoring Function: The transport plane shall enable a monitoring function to indicate whether QoS levels are being met. See TS 101 329-4 [3]. 3) Static and Dynamic Operation: QoS preferences may be signalled on a per call basis or operate on the basis of service capability level agreements using static QoS provisioning. |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 5.6 Interconnection of Transport Domains | It is desirable to be able to provide Service Level Agreements (SLA) governing Inter network communications. End-to-end QoS guarantees may be covered by such Service Level Agreements. 1) Technical mechanisms are required at the interconnection of transport domains to enable the agreed transport QoS to be achieved. NOTE: In this respect guidelines for interconnection between transport networks are provided in ITU-T Recommendation Y.1310 [4]. 2) The transport plane shall allow operation of applications over a combination of separate networks domains. (Note that this does not imply that the network deployment shall be transparent!) ETSI ETSI TR 101 311 V1.1.1 (2001-06) 10 3) Federation: A particular deployment of the transport plane functionality (network) may require the services of a neighbouring network to provide its services. Providing a service area that appears to be transparent to the customer of the network. |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 5.7 Security | Network Operators, Network Providers and Access Providers themselves need security to safeguard their operation and business interests, to meet their obligations to customers, shareholders and to comply with regulatory requirements including lawful interception. The transport plane shall therefore provide an appropriately trusted transport facility for TIPHON applications and address the following issues:- 1) Legal Interception: Depending on local regulatory constraints the transport plane must provide a means for legal interception. 2) Confidentiality of media: Confidentiality is the avoidance of the disclosure of information without the permission of its owner except in cases of legal interception. The transport plane is required to take measures to avoid this unauthorised disclosure. This may be achieved by several means including the use of encryption or prevention of access to the transport network. 3) Confidentiality of address/location information: The transport plane shall allow equipment addresses (both end-user and network-user) and geographical location confidential to end-users and untrusted peer networks. This does not prevent the disclosure of such information to Emergency Call handling or publish-and-subscribe features. 4) Integrity: Integrity is the property that data has not been altered or destroyed in an unauthorized manner. Within the bounds of established quality of service requirements, such as best-effort transmission, the transport plane should deliver transport facilities of a known integrity. 5) Accountability: The transport plane shall provide accounting functionality commensurate with the purposes of maintaining system integrity and accounting for resource usage, to prevent the possibility of fraud while allowing legal investigation. 6) Authentication: the transport plane shall provide means of authenticating packet streams for the purposes of: • identifying the origin of packets for the purposes of non-repudiation, accountability and access control and to prevent masquerading; • authenticating the sender of the packets for access control. 7) Denial of service: Denial of service is the situation whereby an entity fails to perform its function or prevents other entities from performing their functions. Insofar as the attack targets functionality of the transport plane. Transport protocols and their implementations should be designed for functional operation under denial of service attacks. 8) Access control: Access to the network may be subject to authorization. The transport plane shall provide functionality to control the access to the network and block unauthorized usage. 9) Packet/Service access control: The transport plane shall provide functionality to control the access of signalling and media streams to the network. |
5d1879a78e36e0f42fc66f966871f59c | 101 311 | 5.8 Operational Requirements | 1) Maintainability: The transport plane deployments shall be able to change the signalling transport in a smooth way, i.e. it shall be possible to add and delete signalling paths without interruption of the transport between two nodes. ETSI ETSI TR 101 311 V1.1.1 (2001-06) 11 History Document history V1.1.1 June 2001 Publication |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 1 Scope | The present document summarizes the users' views on the main issues related to private directory systems from a functional point of view. It deals with the design of these systems, their interworking as well as interworking between private directory systems and public ones. The present document is applicable to private directory system design and provision. It should be seen as a source of guidelines to users. A corporate directory is an implementation of a private directory for large companies. It is here defined as a repository for information shared by all departments in a corporation, an organization, or an institution. A corporate directory is in contrast to the situation where different departments and functions maintain their own directories for their own purposes, and where such directories are not integrated to constitute an integrated appearance to all users. This does not necessarily imply that a corporate directory needs to be centralized or centrally managed. There are several directory technologies available. Issues concerning establishing a corporate directory are to some degree dependent on the selected technology. Most concepts given in the present document refer to the X.500 directory technology. It does not assume that the reader has a deep understanding of that technology. It is the intention here to keep the technical details down to a minimum. However, it is not possible to discuss deployment of a directory without referring to some X.500 directory concepts, like naming and information structures. Annex A gives a short introduction to the basic X.500 concepts for the benefit of those readers not familiar with such concepts. Although EWOS closed in 1997 and a new organization ISSS (Information Society Standardization System) has been set up to continue producing specifications in same area, EWOS publications remain available for downloading. Therefore, some additional tutorial information can be found on the EWOS Web-pages: http://www.ewos.be/dir/gtop.htm [12] Nevertheless, as indicated in subclause 6.4 "Directory schema", interworking between the different directory systems implies conformance to some X.500 key concepts. In the remainder of the present document, concepts like Directory Information Tree (DIT), directory entry, Distinguished Name (DN), Relative Distinguished Name (RDN), Directory System Agent (DSA), Directory User Agent (DUA), Directory Management Domain (DMD), etc. are assumed to be known by the reader. |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 2 References | References may be made to: a) specific versions of publications (identified by date of publication, edition number, version number, etc.), in which case, subsequent revisions to the referenced document do not apply; or b) all versions up to and including the identified version (identified by "up to and including" before the version identity); or c) all versions subsequent to and including the identified version (identified by "onwards" following the version identity); or d) publications without mention of a specific version, in which case the latest version applies. A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number. >1@ ITU-T Recommendation X.500 (1993) | ISO/IEC 9594-1 (1995): "Information technology - Open Systems Interconnection - The Directory: Overview of Concepts, Models and Services". >2@ ITU-T Recommendation X.501 (1993) | ISO/IEC 9594-2 (1995): "Information technology - Open Systems Interconnection - The Directory: Models". TR 101 153-2 V1.1.1 (1998-01) 7 >3@ ITU-T Recommendation X.511 (1993) | ISO/IEC 9594-3 (1995): "Information technology - Open Systems Interconnection - The Directory: Abstract Service Definition". >4@ ITU-T Recommendation X.518 (1993) | ISO/IEC 9594-4 (1995): "Information technology - Open Systems Interconnection - The Directory: Procedures for Distributed Operation". >5@ ITU-T Recommendation X.519 (1993) | ISO/IEC 9594-5 (1995): "Information technology - Open Systems Interconnection - The Directory: Protocol Specifications". >6@ ITU-T Recommendation X.520 (1993) | ISO/IEC 9594-6 (1995): "Information technology - Open Systems Interconnection - The Directory: Selected Attribute Types". >7@ ITU-T Recommendation X.521 (1993) | ISO/IEC 9594-7 (1995): "Information technology - Open Systems Interconnection - The Directory: Selected Object Classes". >8@ ITU-T Recommendation X.509 (1993) | ISO/IEC 9594-8 (1995): "Information technology - Open Systems Interconnection - The Directory: Authentication Framework". >9@ ITU-T Recommendation X.525 (1993) | ISO/IEC 9594-9 (1995): "Information technology - Open Systems Interconnection - The Directory: Replication". >10@ ITU-T Recommendation X.402 (1995) | ISO/IEC 10021-2 (1996): "Information technology - Message Handling Systems (MHS) - Overall Architecture". >11@ EWOS/ETG 027: "Security Architecture for the Directory". >12@ http://www.ewos.be/dir/gtop.htm. >13@ http://www.ema.org/html/at_work/dirsync.htm. >14@ Internet specification RFC-1274 (1991): "The COSINE and Internet X.500 Schema". >15@ TR 101 153-1 (1998): "Users' views on addressing and directories; Part 1: Requirements for design and interworking". >16@ ITU-T Recommendation I.112 (1993): "Vocabulary of terms for ISDN". >17@ ITU-T Recommendation I.510 (1993): "Definitions and general principles for ISDN interworking". |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 3 Definitions, symbols and abbreviations | In the present document, particular attention should be given to the meaning of the word "private" which, in this context, has been used to indicate that a directory was designed and build by a company or an individual for his own purpose. Where information with privacy aspects is contained in one part of a directory, this part is referred as "restricted use directory". NOTE: This document makes frequent mention of the "X.500 standard" and similar terms relating to "X.500". In the absence of any more precise reference, the occurrence of such an expression in this text may be taken as referring the X.500 series of ITU-T Recommendations, which include [1] to [9]. |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 3.1 Definitions | For the purposes of the present document, the definitions of Part 1 (TR 101 153-1 [15]) apply: business user: User using telecommunication product/services while performing business tasks which have no direct relationship with the telecommunication business. corporate directory: An implementation of a private directory for large companies. A corporate directory is here defined as a repository for information shared by all departments, subsidiaries, etc. in a corporation, an organization, or an institution. These different elementary parts are often placed in different countries and may have separate directory systems interconnected and managed in an harmonized way to build a corporate directory. TR 101 153-2 V1.1.1 (1998-01) 8 directory: System or service allowing users and applications to find information related to a category of people, e.g. employee of a company, subscriber of a network, etc. In the following clauses, unless otherwise specified, the word directory will be used for corporate directory. end-user: A person or machine delegated by a customer to use the service facilities of a telecommunication network, (term 401 of ITU-T Recommendation I.112 [16]) e.g. consumer, residential or business user without any technical knowledge of telecommunication technology using telecommunication terminals. interface: The common boundary between two associated systems (term 408 of ITU-T Recommendation I.112 [16]). interoperability: The ability to communicate between end-users across a mixed environment of various domains, networks, facilities, equipment, etc. from different manufacturers. interworking: Interactions between networks, between end systems, or between parts thereof, with the aim of providing a functional entity capable of supporting an end-to-end communication (ITU-T Recommendation I.510 [17]). IT&T manager: Person responsible in a company for telecommunication and information technology activities. personal directory: Directory managed by an individual for his own use. In general, this is achieved with a personal computer connected to available databases (e.g. public and private directories) and appropriate software to process the local database and add the additional information needed. private directory: Directory built and managed for private purposes. This may be achieved for home use or business use. public directory: Directory built and managed for public use. residential user: User using telecommunication means in private premises. restricted use directory: Directory containing information with privacy aspects. This may be handled as a "restricted part" of a private directory. In any case this means that it contains information which should not be known outside a small group of people. This can be information on individuals or business information containing competitive aspects. Service (Telecommunication Service): That which is offered by an Administration or ROA to its customers in order to satisfy a specific telecommunication requirement (term 201 of ITU-T Recommendation I.112 [16]). NOTE: Bearer service and teleservice are types of telecommunication service. Other types of telecommunication service may be identified in the future. single-location directory: Directory related to users in a single location within a single ownership/business. user: Without specific addition this word is used to identify the telecommunication user community in general, e.g. end- users and IT&T managers. It means user of products or services possibly conforming to standards. |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: ADDMD Administration Directory Management Domain API Application Programming Interface CD ROM Compact Disk Read Only Memory CSV Comma Separated Value DAP Directory Access Protocol dap Directory Access Protocol DIB Directory Information Base DISP Directory Information Shadowing Protocol DIT Directory Information Tree DMD Directory Management Domain DN Distinguished Name DNS Domain Name Server DSA Directory System Agent DSP Directory System Protocol DUA Directory User Agent TR 101 153-2 V1.1.1 (1998-01) 9 ECMA European Computer Manufacturers Association EDP Electronic Data Processing EIDQ European International Directory Inquiry e-mail Electronic mail ETSI European Telecommunications Standards Institute EWOS European Workshop for Open Systems EWOS/EG DIR EWOS Expert Group on Directories ID IDentifier IEC International Electrotechnical Commission ISO International Organization for Standardization ISP International Standardized Profile ISSS Information Society Standardization System IT&T Information Technology and Telecommunications ITU-T International Telecommunication Union - Telecommunication Standardization Bureau JTC1 ISO/IEC Joint Technical Committee No. 1 LAN Local Area Network ldap Lightweight Directory Access Protocol MHS Message Handling System NDS Network Directory System OCG Operational Co-ordination Group OSI Open Systems Interconnection OSITOP European User Group for Open Systems PBX Private Branch Exchange PC Personal Computer PNO Public Network Operator PRDMD Private Directory Management Domain RDN Relative Distinguished Name RFC Request For Comment (Internet Society) SME Small and Medium Enterprises SMTP Simple Mail Transfer Protocol. SNADS System Network Architecture Distribution Services. SOHO Small Office, Home Office. TG Topic Group UPT Universal Personal Telecommunications VAT Value-Added Tax WWW World-Wide Web |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 4 General considerations | Probably the first question to arise when designing a directory system is why a new directory system is needed when there are already so many in the company. The answer may be that a single suitable directory is far better than several outdated ones. The following set of considerations should help in designing a reliable one. |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 4.1 Who will use the directory system? | Several types of users may be identified: the end user or their secretary, switch board attendant, people in charge of the administrative management in the company, people in charge of the technical management of information. In fact, among the operators and service providers there are also of course people in charge of directory management but this is not the purpose of our study, which is user oriented. In addition, it should be recalled that directory information is not only used by people but also by applications (for instance e-mail, videoconferencing, workgroup software and automatic information desks). Obviously, these different users need different information types. TR 101 153-2 V1.1.1 (1998-01) 10 |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 4.2 What is needed in a directory? | A directory is vital to find additional information related to a person, or to something else, on whom/which the enquirer has some piece of information: - someone (or an application) known by name; or - has activities or competencies in a given area; or - is in charge of a department; or - lives or works in a given geographical district, in your or another company, in a private or public area, etc... |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 4.3 What for? | - to get more information; - to pay a visit to someone; - to call someone by phone; - to access a database, a server; - to send a document by mail, fax or e-mail; - to update some information; - to send a purchase order; - to pay a bill via electronic means; or - to manage a commercial transaction. |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 4.4 How is updating to be managed? | The following aspects of management have to be considered: - data management; - management of the directory system; - management of the directory service, and special care should be given to the definition of who is in charge of updating each piece of information in the directory system and what level of security should be given to these tasks. 4.5 And finally, how could a directory system provide your company with competitive advantages? A directory system can make information on a company and its products available to its customers. Should this possibility be developed with the necessary access restrictions then this could help the company's commercial communication and offer competitive advantages - provided the design is appropriate. TR 101 153-2 V1.1.1 (1998-01) 11 |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 5 General specifications | This clause contains indications on the design of directory systems and tools for their management and automated updating. Since paper directories are still widely used for many reasons, electronic directory systems are seen by the users as the best means to provide up-to-date information. A unique centralized system being impracticable, the Information Technology and Telecommunications (IT&T) managers should implement tools to consolidate information from different sources inside and outside the company, since, even within the same company, there are often quite different systems from different providers where some relevant pieces of information are stored and between which interworking is needed. The end-users (person or unit) will wish, in most cases, to put in place their own customized directory system comprising relevant elements obtained from different sources. |
ff9f3f41733e8c81bad8a25e26abfb33 | 101 153-2 | 5.1 Content | The survey (see annex A of TR 101 153-1 [15]) gives a good idea on the main information to be included in a corporate directory. Information about people may be classified in four categories. |
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