Cisco MGX 8850 PXM45 Release Notes page 49

Figure 3
configuration, where the secondary card monitors the working line that is attached to the primary card,
and the primary card monitors the protection line that is connected to the secondary card.
Figure 3
AXSM front card
Secondary card
Standby card
Backcard Backcard
Tx
2
Line failures are always detected at the receive end of the line. This is where a switchover occurs when
a failure is detected. Two different types of switchovers can occur, depending on whether the APS was
configured as unidirectional or bidirectional in the cnfapsln command:
When a failure occurs on a line configured for unidirectional switching, the switch changes lines at
•
the receive end only. A switchover is not necessary at the transmit end because the transmitting back
cards send signals on both lines in the 1 +1 APS configuration.
• When a failure occurs on a line configured for bidirectional switching, a switchover occurs at both
ends of the line.
If the status of the standby line is good, a switchover from the failed active line to the standby is
automatic.
Enter the cnfapsln command to enable an automatic switchover back to the working line after it recovers
from a failure, as shown in the following example:
M8xx0_LA.1.AXSM.a > cnfapsln -w 1.1.1 -rv 2
Table 18
OL-2914-01 Rev D0, July 3, 2003
shows an example of how the APS communication process operates in a crossed APS
Crossed APS Configuration
Remote node
AXSM front card
Primary card
Active card
APS connector
Rx 2 Tx Rx
2
Working line
Active line
Signal
Physical line
describes the configurable parameters for the cnfapsln command.
Release Notes for Cisco MGX 8850 (PXM45), MGX 8850 (PXM1E), and MGX 8830, Software Release 3.0.10
AXSM front card
Secondary card
1
1 1
2
Backcard Backcard Backcard Backcard
Tx
3
Protection line
Stendby line
Limitations and Restrictions for 2.1.x
Local node
AXSM front card
Primary card
Active card Standby card
6
5
APS connector
6
Rx Tx Rx
4
Backcard
3
49