Shortcomings
As detailed in earlier, EoF and EoWDM can only furnish full-rate connections and
cannot (in isolation at least) support subrate or switched Ethernet services. leaving a
Fiber and WDM 223
substantial service gap, particularly since fractional Gigabit Ethernet demands from
SME outfits will form a large portion of overall demand. Hence, carriers must incur
added capital and operational expenditures to deploy higher-layer devices to fill this
void. At current market price-points, EoWDM transponders are best-suited for EPL
speeds exceeding 1.0 Gbps [2]. As a result NGS/MSPP solutions will be more cost-effective
for ???fractional??? service rates in the lower ten-hundreds of megabits range, particularly
if SONET/SDH infrastructures are already in place. As a compromise, some
carriers can use CWDM transport in these slower-rate settings.
Another area of concern for EoF and EoWDM is the lack of fully matured standards.
For example, EoF is generally incapable of supporting full-spectrum management, at
least until switch vendors offer full Ethernet OAM functionality on their ports (see
Ethernet Management). Meanwhile, even though EoWDM provides much better OAM
capabilities, most offerings are still vendor proprietary.
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