ISDN Design for Global Markets
Karen H. Dorato, Lisa J. Klau · AT&T Technical Journal · 1993
Integrated Services Digital Network (ISDN) promises end-to-end, high-speed digital connectivity in a multivendor environment. Over the past several years, applications — such as high-speed data transfer and telemarketing enhancements — have expanded, and the deployment of ISDN customer-premises equipment has increased. However, applications that are available in some countries are not available in others, in part, because standards for the ISDN primary-rate interface (PRI) and the deployment rates of this interface vary from country to country (and carrier to carrier). Thus, true global portability of the protocol is not feasible at this time. However, it is possible to design and develop a PRI implementation that aligns with these varying standards in a single software and hardware base. The implementation requires flexibility and leniency in handling certain protocol elements and may rely on system administration to allow explicit control over some country-specific options of the protocol. This paper reviews the differences found worldwide in the ISDN PRI standards, and describes the flexibility that can be designed into an ISDN PRI implementation to accommodate these inconsistencies.