Page 243 - Optical Switching And Networking Handbook

10_200023_CH09/Bates 1/17/01 9:45 AM Page 228

228 Chapter 9

ment becomes more available. A typical cross-connect is shown in
Figure 9-9, where a TDM architecture is used inside the network
node but a WDM architecture is used across the long-haul network
using 16 on the fiber backbone. This figure looks at the equivalent
of 48 OC-48s cross-connected across DS-3 TDM multiplexers. This
allows a 2400 2400 digital cross-connect system.
An alternative to this figure is to use an optical cross-connect in a
WDM mesh architecture that enables a 64 64 cross-connect with
16 OC-48 to DS-3 multiplexers. This is shown in Figure 9-10 using a
meshed WDM as contrasted with TDM networks. These systems
yield benefits as already described and summarized in the followiing
list:

Patch panel replacements
OC-n switching
Remote access
Video and multicast

Protection rings

Figure 9-9
16
Traditional DCS
in WDM network WDM
(Tellium)
OC-48
OC-48
TDM Mux 48 TDM Mux 48 TDM Mux 48 TDM Mux 32

DS3 DS3

16
2400 x 2400
TDM TDM DS3 DCS TDM
Mux 4 Mux 48
WDM Mux 8 Mux 48 WDM
16 TDM TDM
TDM
TDM
Mux 12 Mux 48
TDM TDM
Mux 16 Mux 48
Source: Tellium