AN IMPLEMENTATION OF ST-II FOR THE HEIDELBERG TRANSPORT-SYSTEM

As part of its work on the Heidelberg Transport System (HeiTS) for multimedia communication, the IBM European Networking Center (ENC) has implemented the Experimental Internet Stream Protocol Version 2 (ST-II). ST-II is a connection-oriented internetworking protocol for multiple-target communication of real-time data such as digital audio and video. This paper summarizes the experiences gained from the design and coding phases. A description of an ST-II service interface and state diagrams, which are missing from the original specification, are provided. The ENC implementation of ST-II fits into the larger scenario of HeiTS: the protocol co-operates with surrounding modules for resource allocation, buffer management, and network access. Comments on the ST-II protocol specification, comparisons with other known implementations, and some first performance measurement results are provided. Experience showed that ST-II is well suited for the transfer of audio and video; however, a clearer specification and some minor design modifications would yield better results.