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

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calculation.  The signal degrade alarm at the path level (SD-P) must be disabled on the port in 
order to suppress these unreliable alarm notifications.  Additionally, the PM data at the path level 
will not be reliable and thus the associated threshold values must be set to 0 in order to avoid 
threshold crossing alerts (TCA) notification on that port.   This limitation does not exist with the 
OC-3/STM-1, OC-48/STM-16 AS (any slot), and OC-192/STM-64 cards. 
 

 
The SDH transport feature of the ONS 15454 addresses a variety of applications, with three 
applications depicted in Figures 3-1, 3-2 and 3-3: 
 

   STM-n 

handoffs. 

 

    SDH signal aggregation, which allows the user to consolidate lower speed SDH signals 

into higher speeds, i.e. STM-1s and STM-4s signals into STM-16 or STM-64 signal. 

 

    Hybrid interfaces including SONET, SDH, Asynchronous TDM and Ethernet traffic with 

Au3 SDH mapping only. 

 

 
Transoceanic cable landings typically have a mixture of both SDH and SONET transmission 
equipment.  These network elements provide drop interfaces of either STM-N or OC-N. If a pass-
through transport element is not available, then a dedicated fiber would be required to transport a 
foreign optical interface inland.  With a pass-through optical transport system, the lower order 
tributary may be mapped into a fraction of the fiber’s capacity and efficiently transported inland. 
Figure 3-2 illustrates a typical mixed SONET/SDH system (for an STM-n hand-off).  The Cisco 
ONS 15454 will be able to drop SDH type interfaces (i.e., STM-1, STM-4) in addition to SONET 
and Traditional TDM based services.  The SDH traffic is seamlessly transported within the 15454 
nodes with an AU-4 (STS-3c) granularity.