Download Best Practices

Best Practices
Protection Switching
Testing protection switching is about confirming that a protected, diversity, or
ring link operates in accordance with its protection switch settings in the presence
of an equipment fault or path error. The manufacturer’s equipment user manual
should specify the switch criteria, and a procedure to check for correct operation.
Table 8-3 describes the types of checks to be performed on each link type.
Table 8-3. Protection Switching Checks
Link Type
Checks
Hot Standby Link
• Correct switching from/to all A side, B side (main - standby) combinations.
• Hitless Rx switching is hitless.
• Tx switching restores correct link/traffic operation within the specified
period.
• No switching is attempted to a standby Tx or Rx if it is in alarm.
• That where a protected system has a preferred side and an automatic return
to the preferred side, that the preferred side is restored automatically when
a fault on the preferred side is cleared. This must be checked for the
preferred Tx and Rx separately.
• The appropriate front panel and management alarms are indicated for the
various states.
Space Diversity Link
• Rx selection is hitless.
• Tx switching restores correct link/traffic operation within the specified
period.
• That no Tx switching is attempted to the standby Tx if it is in alarm.
• The appropriate front panel and management alarms are indicated for the
various states.
Frequency Diversity Link
• Rx and Tx selection is hitless. Putting any Rx or Tx into alarm does not
cause a traffic error.
• The appropriate front panel and management alarms are indicated for the
various states.
280-200019-001 Rev 005a June 2007
8-9