Chapter 2. 9500 MXC Terminals
Vol. II-2-28 Alcatel-Lucent
IDU Protection
This section describes IDU protection options:
Tx switching is not hitless; Rx switching (voting) between the two receive data
streams is hitless (errorless) on hot-standby and space diversity.
Refer to:
• Protected IDUs on page 2-28
• IDU Protection Switch Conditions and Criteria on page 2-30
• IDU Service Restoration Times on page 2-33
Protected IDUs
A protected terminal comprises two IDUs with companion ODUs, and
inter-connecting RJ-45 protection and NMS cables. ‘Y’ cables are available for
trib split/merge. Figure 2-14 illustrates cable options for IDU 20x.
An exception to standard protected IDU operation is provided by the IDU 20x
using the ‘Hot Standby: Non-protected Tributary’ mode which applies to
capacities above 20xE1 / 16xDS1:
• Normal equipment and path protection attributes apply for capacities to 20xE1
/ 16x DS1. Two modes are supported: ‘Hot Standby: Tributary Y-cable’, or Hot
Standby: Tributary Always-On’, which support hitless Rx path switching
(voting) for hot-standby or space diversity applications.
• For higher capacities traffic from the standby IDU is routed to the online IDU
to support termination of 40xE1 or 32xDS1 tribs; 20/16 tribs from each IDU. In
this configuration trib and PSU protection is not supported, however RAC/
ODU and path protection functions are retained. This protection mode is called
‘Hot Standby: Non-protected Tributary’.
IDU Protection Options
IDU 20x Hot-standby, Space Diversity, Ring
IDU 155o Hot-standby, Space Diversity
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