Adtran 1200291L1 User Manual

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Chapter 7. Circuit and Network Redundancy
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MX2800 STS-1 User Manual
7-3
CIRCUIT FAILURE RECOVERY MODE
In Circuit Failure Recovery Mode, two controller cards are installed 
and a single STS-1 line is coming in (see Figure 7-2). In this mode, 
the MX2800 STS-1 can continue operating in the event of a 
controller card failure. When both cards are healthy, the primary 
card actively processes data while the secondary card stands by 
ready to take over if the first fails. The secondary card continuously 
monitors the line and remains framed to the incoming signal. 
See Table 7-1 on page 7-4 for a list of this mode’s configuration 
requirements. 
  
Figure 7-2.  Circuit Failure Recovery Mode
During a card switch, service interruption is experienced on both 
the STS-1 and the DSX-1 connections. However, since the 
secondary controller card remains framed to the incoming signal 
at all times, it is a minimal interruption.
MX2800 STS-1