Page 204 - Optical Switching And Networking Handbook

09_200023_CH08/Batesx 1/17/01 8:20 AM Page 189

High-Speed Applications 189

Express through traffic
Figure 8-1
Add-drop
multiplexing with
SONET/SDH

OADM
M M
U U
X X

Local traffic Local traffic

MUX

DS1
Figure 8-2 DS1 1
Add-drop on the 1
DS3 OC-1 OC-1 DS3
long haul circuit OADM
28 CSU/DSU Router Router CSU/DSU 28
OADM

6 24
9 15

Fiber circuits dropped of
to location "B" and added
back in to location "C"

Figure 8-2 provides a slightly more detailed look at the application
of add-drop multiplexing within a longer-haul circuit. Here, the
inputs at location A are multiplexed into a DS-3 and then onto a