Abstract: In this article, we present a detailed performance
evaluation of a hybrid optical switching (HOS)
architecture called OverspillRouting in Optical Networks
(ORION). The ORION architecture combines
(optical) wavelength and (electronic) packet switching,
so as to obtain the individual advantages of both switching
paradigms. In particular, ORION exploits the possible insertions/extractions, to reduce the necessary
interfaces, do not deteriorate performance and thus the
use of traffic concentrators assure ORION’s economic
viability.
idle periods of established lightpaths to transmit
packets destined to the next common node, or even
directly to their common end-destination. Depending
on whether all lightpaths are allowed to simultaneously
carry and terminate overspill traffic or overspill is restricted
to a sub-set of wavelengths, the architecture
limits itself to constrained or un-constrained ORION. To
evaluate both cases, we developed an extensive network
simulator where the basic features of the ORION architectureweremodeled,
including suitable edge/core node
switches and load-varying sources to simulate overloading
traffic conditions. Further, we have assessed various
aspects of the ORION architecture including two
basic routing/forwarding policies and various buffering
schemes. The complete network study shows that
ORION can absorb temporal traffic overloads, as intended,
provided sufficient buffering is present.We also
demonstrate that the restriction of simultaneous packet
Abstract: We present a detailed performance evaluation of a
hybrid optical switching architecture called OverspillRouting in
Optical Networks (ORION). The ORION architecture combines
wavelength and (electronic) packet switching, so as to obtain the
advantages of both switching paradigms. We have developed an
extensive network simulator where the basic features of the
ORION architecture were modeled, including suitable loadvarying
sources and edge/core node architectures. Various aspects
of the ORION architecture were studied including the routing
policies used (i.e. once ORION always ORION and lightpath reentry)
and the various options available for the buffer
architecture. The complete network study shows that ORION can
absorb temporary traffic overloads, as intended, provided
sufficient buffering is present.