Juniper JUNOSE 11.2.X MULTICAST ROUTING, Configuration Manual

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You configure a working interface on the primary port and a corresponding protect interface
on the redundant port of the I/O module. The working interface provides the primary
connection, and the protect interface provides the redundant connection.
The router sends and receives data through both interfaces; however, in normal operation,
only the signal on the working interface is used. If the signal on the primary interface fails,
the router can use the signal on the protect interface. The process by which the router
switches to the protect interface is called
switchover .
When you configure APS/MSP, you must assign a working interface and a corresponding
protect interface to a unique group. This group establishes the relationship between the
interfaces. Within the group, each interface is identified by an APS/MSP
channel number .
For information about identifying the channel number, see “Numbering Scheme” on
page 79.
You must pair a working interface and its corresponding protect interface on an I/O
module to form a valid linear APS 1+1 group. For example, on an I/O module that provides
four working (primary) ports and four protect (redundant) ports, the working interface
ports are numbered 0–3, and the protect interface ports are numbered 4–7. Table 6 on
page 72 lists the pairings required to form four valid APS 1+1 groups on this I/O module.
Each working/protect port pair (for example, port 0 and port 4) forms a valid APS 1+1
group.
Table 6: Sample Pairings for Valid APS/MSP Groups
With This Protect Port Pair This Working Port
4 0
5 1
6 2
7 3
Automatic Switchover
Provided you have not issued the aps lockout command for the protect interface, the
router switches over to the protect interface if it detects signal failure. You can set the
SONET/SDH alarms that determine signal failure and signal degradation.
Manual Switchover
When the router is running and you have configured the I/O module for APS/MSP, you
can cause switchover by issuing the
aps force or aps manual command.
Switching Mechanisms
E Series Broadband Services Routers support both bidirectional and unidirectional APS
switching modes. By default, the router uses bidirectional switching mode.
Copyright © 2010, Juniper Networks, Inc. 72
JunosE 11.2.x Physical Layer Configuration Guide