6). Service providers may, therefore, deploy MSPPs to provide
multi-service access, while still making use of their multi-billion dollar investment in
traditional SONET equipment.
How Much Ethernet Is in an MSPP?
Mapping Ethernet frames into SONET represents the initial and most fundamental
issue with EoS. All Ethernet-enabled MSPPs perform this function. However, Ethernet
means more than just a frame format; it also includes a switching technology??”Ethernet
Medium Access Control (MAC) bridging, more precisely. Historically, the integration of
Ethernet switching into SONET systems has been met with mixed results.
The issue is only partly technical. While equipment vendors certainly can design new
systems that feature high performance, low-cost combinations of Ethernet switching
and full SONET ADM functionality, most implementations have grown from systems
that were optimized for either Ethernet or SONET. These designs carry the burden of
tradeoffs made early in the design process.
More limiting than that, however, are the current operating environments of the
largest service providers. These providers have large embedded operations support
systems (OSSs) that cover all aspects of their optical transport networks (e.
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