Chapter 20
  |  ERPS Commands
–  503  –
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Recovery with revertive mode is handled in the following way:
a.
The RPL Owner Node, upon reception of an R-APS (NR) message and in 
the absence of any other higher priority request, starts the WTB timer 
and waits for it to expire. While the WTB timer is running, any latent R-
APS (MS) message is ignored due to the higher priority of the WTB 
running signal.
b.
When the WTB timer expires, it generates the WTB expire signal. The 
RPL Owner Node, upon reception of this signal, initiates reversion by 
blocking the traffic channel on the RPL, transmitting an R-APS (NR, RB) 
message over both ring ports, informing the ring that the RPL is 
blocked, and flushes its FDB.
c.
The acceptance of the R-APS (NR, RB) message causes all ring nodes to 
unblock any blocked non-RPL that does not have an SF condition. If it is 
an R-APS (NR, RB) message without a DNF indication, all Ethernet Ring 
Nodes flush their FDB. This action unblocks the ring port which was 
blocked as a result of an operator command.
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Recovery with non-revertive mode is handled in the following way:
a.
The RPL Owner Node, upon reception of an R-APS (NR) message and in 
the absence of any other higher priority request does not perform any 
action.
b.
Then, after the operator issues the erps clear command at the RPL 
Owner Node, this ring node blocks the ring port attached to the RPL, 
transmits an R-APS (NR, RB) message over both ring ports, informing 
the ring that the RPL is blocked, and flushes its FDB.
c.
The acceptance of the R-APS (NR, RB) message triggers all ring nodes to 
unblock any blocked non-RPL which does not have an SF condition. If it 
is an R-APS (NR, RB) message without a DNF indication, all ring nodes 
flush their FDB. This action unblocks the ring port which was blocked as 
result of an operator command.
Example 
Console(config-erps)#non-revertive
Console(config-erps)#
propagate-tc
This command enables propagation of topology change messages for a secondary 
ring to the primary ring. Use the 
no
 form to disable this feature.
Syntax 
[
no
]
 propagate-tc
Default Setting 
Disabled