CLI Reference Guide-R04

Chapter 21 | ERPS Commands
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a. If no other higher priority commands exist, the ring node, where a manual
switch command was issued, blocks the traffic channel and R-APS channel
on the ring port to which the command was issued, and unblocks the other
ring port.
b. If no other higher priority commands exist, the ring node where the
manual switch command was issued transmits R-APS messages over both
ring ports indicating MS. R-APS (MS) message are continuously transmitted
by this ring node while the local MS command is the ring node’s highest
priority command (see Table 99 on page 571). The R-APS (MS) message
informs other ring nodes of the MS command and that the traffic channel is
blocked on one ring port.
c. If no other higher priority commands exist and assuming the ring node was
in Idle state before the manual switch command was issued, the ring node
flushes its local FDB.
d. A ring node accepting an R-APS (MS) message, without any local higher
priority requests unblocks any blocked ring port which does not have an SF
condition. This action subsequently unblocks the traffic channel over the
RPL.
e. A ring node accepting an R-APS (MS) message, without any local higher
priority requests stops transmitting R-APS messages.
f. A ring node receiving an R-APS (MS) message flushes its FDB.
◆ Protection switching on a manual switch request is completed when the above
actions are performed by each ring node. At this point, traffic flows around the
ring are resumed. From this point on, the following rules apply regarding
processing of further manual switch commands:
a. While an existing manual switch request is present in the ring, any new
manual switch request is rejected. The request is rejected at the ring node
where the new request is issued and a notification is generated to inform
the operator that the new MS request was not accepted.
b. A ring node with a local manual switch command which receives an R-APS
(MS) message with a different Node ID clears its manual switch request and
starts transmitting R-APS (NR) messages. The ring node keeps the ring port
blocked due to the previous manual switch command.
c. An ring node with a local manual switch command that receives an R-APS
message or a local request of higher priority than R-APS (MS) clear its
manual switch request. The ring node then processes the new higher
priority request.
◆ Recovery for manual switching under revertive and non-revertive mode is
described under the Command Usage section for the non-revertive command.