Frame Relay Systems should be as simple as possible but not simpler Albert Einstein Many people are familiar with the first widely used service of the datacomms era—. As a mature product of the ‘analogue era’, it is a complex protocol. Much of this complexity arose from the need to protect against errors introduced by noisy analogue transmission circuits and the comparatively long round-trip delay caused by their low transmission speeds. Frame Relay, by contrast, is very much a product of the ‘digital age’, exploiting the much lower error rates and higher transmission speeds of modern digital systems. In particular, Frame Relay. | Total Area Networking ATM IP Frame Relay and SMDS Explained. Second Edition John Atkins and Mark Norris Copyright 1995 1999 John Wiley Sons Ltd Print ISBN 0-471-98464-7 Online ISBN 0-470-84153-2 3 Frame Relay Systems should be as simple as possible but not simpler Albert Einstein Many people are familiar with the first widely used service of the datacomms era . As a mature product of the analogue era it is a complex protocol. Much of this complexity arose from the need to protect against errors introduced by noisy analogue transmission circuits and the comparatively long round-trip delay caused by their low transmission speeds. Frame Relay by contrast is very much a product of the digital age exploiting the much lower error rates and higher transmission speeds of modern digital systems. In particular Frame Relay has its roots in the Integrated Services Digital Network the ISDN Griffiths 1992 . THE ISDN The ISDN is the latest step in the evolution of the PSTN. The early 1970s saw the widespread introduction of digital transmission into the telephone network. This was followed in the late 1970s by digital switching systems with computer control of switching operations together with powerful message-based inter-processor signalling between the switching centres. This combination of digital switching and digital transmission systems the so-called Integrated Digital Network or IDN promised great flexibility for new service innovation and reductions in operating costs. But the local access circuit between the user and the local exchange was still analogue. It was still just a telephone network. Driven by the increasing importance of non-voice services the 1980s saw the next logical step in the evolution of the telephone network in which the digital connection is taken all the way to the user making it equally suitable for voice and non-voice services. To exploit the power of this all-digital 44 FRAME RELAY Figure Separation of user information and signalling
