ADTRAN 4200659L1 - Manual (Page 137)

Chapter 7. Circuit and Network Redundancy
61200659L1-1 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