Performance of ATM protocols for video services

Asynchronous transfer mode (ATM) operation has now been recognised as a basis for a multiservice network that will permit broadband operation up to a high bit rate. The CCITT Study Group XVIII has made some progress towards the definition of such a network but much remains to be done before complete Recommendations can be produced and viable systems implemented. The main problem is that, although the broadband ISDN network will provide a (digital) bearer service, it cannot be defined in isolation. The teleservices to be carried on the B-ISDN need to be considered in relation to both the interfacing to the bearer network and the effects of impairments produced by the network. Interest has been concentrated on both interactive and distributive video services because they are likely to constitute a major source of traffic for the B-ISDN. An attempt has been made to model conditional replenishment coded video signals carried over an ATM network under a range of traffic loadings and so characterise the impairments to the teleservices that would be produced by the bearer network. This information can then be used to assess the human factors perception of the video services that might be carried by the network