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Cost Implications and Financial Trending 231

400,000
Figure 9-11
350,000
Cost model of
dedicated fiber 300,000
versus DWDM 250,000
Cost 200,000
(Scientific Atlanta)
150,000
100,000
50,000
0
0 30 60 90 120 150
Miles

DWDM Dedicated Fiber

Source: Scientific Atlanta

gle head-end-to-hub link at just over 30 route miles, or at the initial
hub location. After the initial interconnect, the expected cost differ-
ential is obvious. Savings for DWDM, compared with the cost of fiber,
range from 12 to 30 percent. The implications of this simple analysis
are significant. DWDM technology is expected to prove cost-effective
for the case of insufficient fiber, but also another strong business
case for DWDM may be realizable even when sufficient fiber does
exist.

Costs for the Metropolitan

Networks

Not all networks need to be long distance to save considerable
amounts of money. In metropolitan networks, the savings can mount
quickly using DWDM and optical cross-connection systems. Com-
paring the optical networking and SONET architectures in a metro-
politan area shows between 20 and 40 percent overall savings, with
all things being equal. Let’s look at a scenario of using optical switch-
ing and cross-connection with a WDM attitude. Compare this with a