Web Management Guide-R04

Table Of Contents
Chapter 13
| Basic Administration Protocols
Ethernet Ring Protection Switching
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Figure 328: Showing Configured ERPS Rings
ERPS Forced and
Manual Mode
Operations
Use the Administration > ERPS (Configure Operation) page to block a ring port
using Forced Switch or Manual Switch commands.
Parameters
These parameters are displayed:
Domain Name – Name of a configured ERPS ring.
Operation – Specifies a Forced Switch (FS) or Manual Switch (MS) operation on
the east or west ring port.
Forced Switch – Blocks specified ring port. (Options: West or East)
A ring with no pending request has a logical topology with the traffic
channel blocked at the RPL and unblocked on all other ring links. In this
situation, the FS command triggers protection switching as follows:
a. The ring node where an FS 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. The ring node where the FS command was issued transmits R-APS
messages indicating FS over both ring ports. R-APS (FS) messages
are continuously transmitted by this ring node while the local FS
command is the ring nodes highest priority command (see
Table 34 on page 506). The R-APS (FS) message informs other ring
nodes of the FS command and that the traffic channel is blocked on
one ring port.
c. A ring node accepting an R-APS (FS) message, without any local
higher priority requests unblocks any blocked ring port. This action
subsequently unblocks the traffic channel over the RPL.
d. The ring node accepting an R-APS (FS) message, without any local
higher priority requests stops transmission of R-APS messages.
e. The ring node receiving an R-APS (FS) message flushes its FDB.