scope:

This first part of ETS 300 478 describes the support of connectionless data service on Broadband Integrated Services Digital Network (B-ISDN) in accordance with:

- ETS 300 217 [2], which details the stage 1 aspects for the Connectionless Broadband Data Service (CBDS);

- ITU-T Recommendation I.113 [5], which defines connectionless service (vocabulary);

- CCITT Recommendation F.812 [4], which provides a service description of a CBDS. CCITT Recommendation F.812 [4] generally describes the service to include:

- source address validation;

- addresses based on CCITT Recommendation E.164 [3] numbering;

- point-to-point and multicast information transfer;

- address screening for point-to-point and multicast information transfer;

- network capabilities for charging;

- interworking with other ConnectionLess and Connection oriented data services;

- Quality of Service (QoS) parameters.

- ITU-T Recommendation I.211 [6], which describes connectionless data service aspects. ITU-T Recommendation I.211 [6] identifies two configurations, type (i) and type (ii) to support connectionless data service. In type (i), a Connectionless Service Function (CLSF) is installed outside the B-ISDN. In type (ii), a CLSF, which handles routeing of data to be transferred based on connectionless techniques, is installed within the B-ISDN;

- ITU-T Recommendation I.327 [8], which describes "high layer capabilities" for the support of services (e.g. connectionless service) and gives functional architectural models for the cases mentioned in F.812 Recommendation [4]; - ITU-T Recommendation I.362 [9], which specifies the use of ATM Adaptation Layer (AAL) type 3/4 for connectionless data services (although I.362 recognizes that the use of other AAL types is for further study) and identifies that routeing and addressing are provided by the layer located above AAL type 3/4;

- ETS 300 349 [10], which specifies AAL type 3/4;

- ITU-T Recommendation I.364 [1], which specifies the support of Broadband Connectionless Data Bearer Service (BCDBS) on B-ISDN.

This ETS relates to type (ii) (direct) provision of connectionless service, using B-ISDN connectionless service. However, aspects of this ETS may be applied to some type (i) provision of connectionless service. This ETS describes the framework for network support of CBDS and the protocol used to support CBDS at the User Network Interface (UNI). The protocol used to support CBDS at the Network Node Interface (NNI) is described in 300 479-1 [14].