scope:

This Technical Report focuses on analysis of the impact of changing traffic characteristics on the PSTN, and the use of the PSTN for access to the Internet. The availability, reliability, and survivability aspects of the interactions between the Internet and the PTN, as well as the impact of that interaction on other PTN services, are addressed from an end-user's viewpoint.

Purpose

Over the past few years, the traffic characteristics of telecommunications networks have been changing. For example, Internet users are adding many calls with shorter and longer holding times than usual. This change, in turn, raises concerns about maintaining the performance and reliability of telecommunications services using the Public Switched Telecommunications Network (PSTN). The purpose of this Technical Report is to describe the challenges and propose some potential solutions to help maintain a high level of availability, reliability, and survivability of the PSTN.

Application

The intended audience of this Technical Report includes providers of telecommunications networks and services (including Internet services), as well as suppliers of telecommunications equipment and support systems. Network-provider personnel - including designers, planners, traffic engineers, and individuals in charge of operations, administration, maintenance, and management - can use this document to enhance the performance and survivability of their networks. Telecommunications equipment and support system suppliers can use this document to guide the design and building of equipment to improve network survivability performance.

Outline

Section 2 provides an overview of related work at the different national and international standards bodies, as well as at other industry forums and committees. Section 3 is an introduction to the Technical Report. Section 4 discusses the challenge of changing network traffic characteristics in the PTN with the advent of the Internet. Section 5 is devoted to Internet and discusses the Internet industry structure, architecture, technologies, reliability/availability objectives, Quality of Service (QoS), and trends. Section 6 addresses the PTN architecture and some reliability/availability objectives for a hypothetical reference connection of a local exchange PTN. Section 7 focusses on the interactions between the Internet and the PTN. In particular, it provides connection architectures, failure modes, parameter descriptions and measurements, as well as failure analysis methods. Section 8 provides some reliability/survivability solutions and suggestions to general industry, including failure prevention/mitigation methods. Section 9 gives some recommendations to standards organizations. Finally, Section 10 summarizes the findings of this Technical Report.