Aps Switch Occurs Even Though Aps Forced Switch In Effect; Aps Line Is Failing To Switch; Large Cell Loss When Performing A Front Card Switchover; Aps Service Switch Description - Cisco BPX-BXM-155-8DX Installation And Configuration Manual

Operational Problems
Explanation: This is normal operation. An APS clear switch request causes the APS switching
mechanism in the BXM to initialize. This will cause a switch back to the working line if the working
line is in better shape than the protection line. If the protection line is not faulty, no switch will occur.

APS Switch Occurs even though APS Forced switch in effect

Description: A forced switch to protection line is performed. LOS on protection line causes a switch
back to working line even though a forced switch is in progress
Explanation: Signal Fail on Protection line has higher priority than Forced switch. Whenever the
protection line is in failure, there will be a switch to working line, even if the working line is failed or
there is a forced W->P in effect.

APS line is failing to switch

Description: The user issues an APS forced or manual switch request but no switch occurs
Investigation: This could be due to a forced, manual, or lockout switch being in progress and a clear
switch is required (switchapsln Ln1 Ln2 1). Need to issue an APS clear switch (switchapsln) to exit
forced, manual, or lockout switch state.
If running the ITUT APS standard protocol which does not report an Architecture Mismatch APS alarm
the problem could be that one end of the line is bi-directional and the other is uni-directional.
Check that configuration is the same on both ends, specifically uni/bidirectional mode, 1:1/1+1
configuration.
A manual switch will not occur if the standby line is in alarm.

Large cell loss when performing a front card switchover

Description: A line configured for APS 1+1 line redundancy has its active front card switched either
due to card failure, switchyred (switchcdred), or resetting the card. A loss of cells is observed.
Investigation: Cell loss at card switchover is not due to faulty APS. It is a result of the card redundant
switch (YRED switch) and there will be up to 250ms worth of traffic disruption during BXM front card
switchovers.

APS service switch description

Description: What is an APS service switch? Does it work on APS 1:1 configurations?
Investigation: An APS service switch is applicable only to APS 1+1 configuration. It lets you switch
all the APS lines on a card by using a single switchapsln command with an "s" option at the end of the
command. All APS lines on this card pair will be switched and made active on a single backcard
allowing the other backcard to be removed for service.
IMPORTANT: Be sure that the associated front card is active for the backcard that is to remain in the
rack. You might have to perform a switchcdred so that the backcard that the service switch switches to
has its associated front card active. A service switch is not required in order to remove a BXM front
card with APS 1+1 lines on it. The card redundancy will handle the switch to the other card without
affecting the lines.
Cisco BPX 8600 Series Installation and Configuration
29-14
Chapter 29
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001
Troubleshooting