Transmission and Multiplexing (TM); Synchronous Digital Hierarchy (SDH); SHD Based User Network Access; Physical Layer Interfaces for Broadband Integrated Services Digital Network (B-ISDN) Applications Second Edition
This draft second edition European Telecommunication Standard (ETS) defines the physical layer interface to be applied to the SB and TB reference points of the reference configurations of the Broadband Integrated Services Digital Network (B-ISDN) Synchronous Digital Hierarchy (SDH) based User-Network Interface (UNI) at 155 520 kbit/s and 622 080 kbit/s. It addresses separately the physical media and the transmission system used at these interfaces and addresses also the implementation of UNI related Operation Administration and Maintenance (OAM) functions. The selection of the physical medium for the interfaces at the SB and TB reference points should take into account that optical fibre is agreed as the preferred medium to be used to cable customer equipment. However@ in order to accommodate existing cabling of customer equipment@ other transmission media (e.g. coaxial cables) should not be precluded. Also@ implementations should allow terminal interchangeability. This ETS reflects in its structure and content the desire to take care of such early configurations and introduces a degree of freedom when choosing a physical medium at the physical layer. Edition 2 of this ETS defines newly considered points since the publication of edition 1@ dealing particularly with jitter characteristics at the B-UNI@ sub-rates of STM-1 applied at the SB and TB reference points of the reference configurations of the B-ISDN SDH - based UNI (if required in this ETS)@ enhanced definitions concerning the cell delineation algorithm and changes of the SDH overhead octet allocation at the B-UNI. The production of this ETS has taken into account the recommendations given in ITU-T Recommendation I.432.1 and I.432.2 [7].