Cisco Cisco ONS 15454 SONET Multiservice Provisioning Platform (MSPP) Guía De Diseño

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and post-amplification; these components that may or may not be present in an OADM, 
depending upon its design. 
 

 

 

 

 
Most DWDM systems support standard SONET/SDH optical interfaces to which any SONET 
compliant client device can attach.  On the client side there can be SONET/SDH terminals or 
ADMs, ATM switches, or routers.  Transponders are used to convert incoming optical signals into 
the precise ITU-standard wavelengths to be multiplexed. 
 
Within the DWDM system a transponder converts the client optical signal back to an electrical 
signal and performs the 3R functions (see Figure C-23).  This electrical signal is then used to 
drive the WDM laser.  Each transponder within the system converts its client's signal to a slightly 
different wavelength.  The wavelengths from all of the transponders in the system are then 
optically multiplexed. 
 
In the receive direction of the DWDM system, the reverse process takes place. Individual 
wavelengths are filtered from the multiplexed fiber and fed to individual transponders, which 
convert the signal to electrical and drive a standard interface to the client. 
 

 

 

 
Using the ONS 15454 with its OC48ELR ITU optics cards reduces or eliminates the need for 
transponders.  This architecture provides a cost-effective solution for Metro DWDM network 
applications. 
 

 
Some DWDM systems transponders are optical-electrical-optical (OEO) devices that transforms 
(maps) an incoming wavelength into a DWDM wavelength.  Using the ONS 15454 OC48ELR ITU 
optical cards reduces or eliminates (based on your channel plan) the need for transponders.  
Figure C-24 shows a DWDM system with transponders.