Sources of failure in the public switched telephone network

Author

Kuhn, D. Richard

Author_Institution

Software Quality Group, Nat. Inst. of Stand. & Technol., Gaithersburg, MD, USA

Volume

30

Issue

4

fYear

1997

fDate

4/1/1997 12:00:00 AM

Firstpage

31

Lastpage

36

Abstract

What makes a distributed system reliable? A study of failures in the US public switched telephone network (PSTN) shows that human intervention is one key to this large system´s reliability. Software is not the weak link in the PSTN system´s dependability. Extensive use of built-in self-test and recovery mechanisms in major system components (switches) contributed to software dependability and are significant design features in the PSTN. The network´s high dependability indicates that the trade-off between dependability gains and complexity introduced by built-in self-test and recovery mechanisms can be positive. Likewise, the tradeoff between complex interactions and the loose coupling of system components has been positive, permitting quick human intervention in most system failures and resulting in an extremely reliable system

Keywords

built-in self test; electronic switching systems; software reliability; switches; system recovery; telecommunication computing; telecommunication switching; telephone networks; PSTN; USA; built-in self-test; complexity; distributed system reliability; failure sources; human intervention; loose coupling; public switched telephone network; recovery mechanisms; software dependability; switches; system components; Communication cables; Distributed computing; FCC; Hardware; Humans; Intelligent networks; Personnel; Software maintenance; Switches; Telephony;

fLanguage

English

Journal_Title

Computer

Publisher

ieee

ISSN

0018-9162

Type

jour

DOI

10.1109/2.585151

Filename

585151