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204 Chapter 8

Figure 8-15 L2/L3 Switch
The metropolitan
SONET network
T1/E1, T3, OC-3
Frame Relay, ATM

SONET Ring
OC-12
OC-48
OC-192

SONET
add-drop MUX

learning/training, telemedicine, global information systems, intra-
nets for e-mail and shared databases/applications for e-government,
and business-to-government (B2G) and extranet access. Individual
agencies and school districts usually build independent islands of
information technology around themselves, isolated from each
other. Different software and hardware platforms are deployed, and
information cannot be shared. These entities failed to leverage their
economies of scale for greater buying power. This has resulted in
higher communications and information technology costs and dupli-
cation of effort.
Things are changing, however. Innovative communities are col-
laborating to pool resources to create new network infrastructures
that enable higher-performance networked applications at lower
overall costs. By building a high-speed communications grid among
public entities, a community may be able to break down traditional
barriers and streamline operations by reducing duplicated efforts.
Figure 8-16 shows how this might work.