Page 91 - Optical Switching And Networking Handbook

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76 Chapter 3

Figure 3-18
Add-drop
multiplexing
with SONET OC-1 OC-1 OC-1

DSI
DS1

TEAMFLY
additional new signals can be added in place of the data stream
dropped out of the higher-speed signal. A single-stage add-drop mul-
tiplexing function can multiplex various inputs into an OC-n signal.
At an add-drop site, only those signals which need to be accessed are
dropped and inserted. The remaining traffic continues through the
network switching system without requiring special processing.

SONET Topologies

Several different topologies can be used in a SONET network
employing various multiplexers.These include the normal topologies
most networks have become accustomed to over the years, such as
Point-to-point
Point-to-multipoint

Hub and spoke
Ring

The variations enable more flexibility for SONET in the WANs
built by the carriers and now becoming the method of choice at many
large organizations.With each of the topologies, larger organizations
are finding the benefits of installing highly reliable interoperable
equipment at private network interfaces and access points to public
networks.

®
Team-Fly