grooming outside ASON. Alternatively, band-
width allocation can be carried out using a wave-
length allocation scheme that can allow mixing
of a number of clients together. Network seg-
ment – e.g. metro versus core networks – may be
the most decisive factor when choosing among
different traffic grooming paradigms.
Automatically switched optical networks can
allocate resources on demand, accommodate
lower priority traffic where and when there is
bandwidth available, and drop this traffic if nec-
essary in case of congestion or in case higher
priority traffic needs to be restored because of
fibre break or other failure. The dynamic provi-
sioning, bandwidth efficiency, traffic engineer-
ing and fast restoration capabilities of ASON
make it a very powerful multi-client platform
that opens new possibilities for service integra-
tion, the introduction of new services, new pric-
ing paradigms and business models.
6 Summary
Optical transmission has experienced a dramatic
growth in the past years with the advent of
DWDM that has enabled multi-terabit optical
transmission over distances of several hundreds
of kilometres. Yet the potential of optical tech-
nology is still far from being exploited. Optical
network functionality in wavelength-routed net-
works may well be the key to high capacity
intelligent networks that utilise their resources in
an efficient way and can provide a range of dif-
ferentiated services. Optical switching provides
an economical way to handle large amounts of
traffic and to build reliable networks. It leads to
a dramatic reduction of the required processing
capacity and to rationalised network architec-
tures without duplication of functionality and
expensive superfluous interfaces. The on-going
intense standardisation and development work in
the past years can mean that such networks are
not all that far from being a reality; they are in
fact leaving the labs and entering the market as
we speak. Although the winning technologies
are not yet fully identified and the detailed logis-
tics of networks and architectures are still to be
finalised, one reality has clearly emerged: Opti-
cal switching will be an integral and determining
part of next generation networks.
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