g., TIRKS,
NMA, and other systems from Telcordia). These systems are optimized to model pointto-
point transport of circuits. Simple EoS mappings (e.g., point-to-point EoS ???circuits???
using GFP/VCAT/LCAS) fit well within the current models. However, more complex
data functionality, such as Ethernet switching, is complex and expensive to model in
these systems. Operational support for Ethernet switching, for instance, requires large
investments from these service providers, either in the embedded OSSs or in new OSSs
that handle the advanced data functions of MSPPs and other highly integrated systems.
Investment has been slow and has focused on opportunities where revenues are
relatively large and easily forecasted, e.g., in dedicated networks for large corporate
customers.
Drivers for This Solution
As mentioned previously, cost was the initial driver to deliver Ethernet services over
SONET. As Ethernet services emerged in the mid-1990s, service providers looked for
ways to lower service delivery costs by integrating Ethernet with the rapidly expanding
SONET infrastructure. This, in turn, motivated equipment vendors to build network
elements that could carry Ethernet over SONET.
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