Alcatel-Lucent 9500 MXC - IDU Protection Switch Conditions and Criteria

Chapter 2. 9500 MXC Terminals
Vol. II-2-30 Alcatel-Lucent
Next:
• IDU Protection Switch Conditions and Criteria
• IDU Service Restoration Times
IDU Protection Switch Conditions and Criteria
Tx and Rx are switched separately except for a Tx online switch event where the
Rx Online function will follow the Tx to put Tx Online and Rx Online on the
same IDU. This occurs providing there is no blocking condition to prevent an RX
online switch
1
.
The primary-designated IDU is default online for Tx and Rx
2
.
• Online for Tx means that it is transmitting.
• Online for Rx means that it is controlling the Rx protection switch function and
is sending Rx data to the trib ports.
The protection cable must be correctly installed between protected IDUs for
protection to operate.
Data is provided for:
• Switching Guard Times
• Switch Conditions: IDU 20x and IDU 155o
• Tx Switch Criteria
• Rx Switch Criteria: IDU 20x and IDU 155o
Switching Guard Times
To prevent protection switch oscillation a switch oscillation guard time
mechanism applies to all forms of online protection switching
3
. The mechanism
is described below.
• A period of guard time begins immediately after each protection switch occurs.
• No protection switches are permitted during the guard time. Protection
switching may resume once the guard time has elapsed.
• To damp possible oscillations in the system the guard time is regularly adjusted,
using the following rules:
• The guard time doubles after each switch (up to the maximum)
1
An Rx blocking condition will occur if there is an Rx path alarm on the partner IDU or if the current IDU
is locked online for Rx.
2
Except for IDU 20x when operated in the Hot-standby: Non-protected Tributary mode. In this mode both
IDUs are online to receive data from its directly-connected ODU.
3
It does not apply to Rx diversity-bus (hitless) path switching.