Perform this task to configure IPS on an SRP
interface. This is an optional task.
Intelligent Protection Switching (IPS) provides
IP self-healing and restoration, and performance monitoring after a link or
node failure. There are two SRP IPS modes:
-
Automatic SRP IPS mode takes effect when the
SRP ring detects an event, a fiber cut, or a node failure, and remains in
effect until the trigger condition is cleared. Once the trigger is cleared, the
SRP IPS mode remains in effect until the wait-to-restore (WTR) value expires.
-
User-configured SRP IPS mode takes effect as
soon as you enter the command and remains in effect until it is removed by a
user command or overridden by an SRP IPS command with higher priority. You can
use the
no srp ips request
forced-switch global configuration command or the
srp
remove
manual-switch EXEC
command to negate a user-configured command.
A a user-configured, forced-switch adds a
high-priority protection switch wrap on each end of a specified span by
entering the user-configured
srp ips request forced-switch
command. For example, you can enter an
srp ips request forced-switch
command to force data traffic to one side of the ring
before a DPT PLIM is removed from a router slot, or in response to an event.
This table describes the IPS requests in the
order of priority, from higher to lower.
Table 1. Explanation of SRP IPS User Requests
SRP IPS Request
|
Description
|
Forced-switch
|
Adds a high-priority protection switch
wrap on each end of a specified span by entering the user-configured srp ips
request forced-switch command.
|
Manual-switch
|
Adds a low-priority protection switch
wrap on each end of a specified span by entering the user-configured srp
request manual-switch command.
|
Note |
Before removing the DPT PLIM, you can use the
srp ips request forced-switch command on both sides of the interface that is to
be removed.
|
If an automatic or user-configured protection
switch is requested for a given span, the node that receives the protection
request issues a protection request to the node on the other end of the span
using both the short path over the failed span, because the failure may be
unidirectional, and the long path around the ring.
As the protection requests travel around the
ring, the protection hierarchy is applied. For example, if a high-priority
Signal Fail (SF) request enters the ring, it overrides a preexisting
lower-priority request. If an event or a user-configured command enters a
low-priority request, it is not allowed if a high-priority request is present
on the ring.
Note |
An exception is that multiple signal-fail and
forced-switch requests can coexist on the SRP ring and will bisect the ring if
they occur on separate fiber links.
|
All protection switches are performed
bidirectionally and enter wraps at both ends of a span for transmit and receive
directions, even if a failure is only unidirectional.