ATM as a universal transfer medium for user information, signalling and operation and maintenance

ATM has been selected as the transer mode for future integrated broadband networks. It has already been highlighted in numerous papers that ATM is capable of transferring voice, video and data. This paper describes the capability of ATM to transfer also signalling information and the impact of ATM on signalling as well as the capability of ATM to build a very powerful maintenance concept which can be used ubiquitous; i.e. as well in the transmission as in the switching systems. First this paper will describe the impact of ATM on signalling. This impact can be seen on all levels of the protocol stack. On level one the disappearance of a fixed D channel as in NISDN introduces the need for a meta-signalling concept for multidrop environments. The opportunities generated by this meta-signalling are described here. The impact on level 2 is the need to introduce a segmentation and reassembly layer On level 3 the impact of ATM is mostly reflected through the deftnition of the ATM bearer service. The maintenance philosophy of a future broadband network is also a keypoint to its success. Since ATM can be considered as a switching as well as a transmission principle, a universal maintenance concept can be defined This maintenance philosophy includes where and what sort of maintenance information and how this is gathered. Secondly, how this information is then transported to the maintenance centers and finally how this information is interpreted.