LevelOne GTL-2691 - Manual (Page 1098)

C HAPTER 38 | ERPS Commands
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non-erps-dev-
protect
This command sends non-standard health-check packets when an owner
node enters protection state without any link down event having been
detected through SF messages. Use the no form to disable this feature.
S YNTAX
[no] non-erps-dev-protect
D EFAULT S ETTING
Disabled
C OMMAND M ODE
ERPS Configuration
C OMMAND U SAGE
◆ The RPL owner node detects a failed link when it receives R-APS (SF -
signal fault) messages from nodes adjacent to the failed link. The
owner then enters protection state by unblocking the RPL. However,
using this standard recovery procedure may cause a non-EPRS device
to become isolated when the ERPS device adjacent to it detects a
continuity check message (CCM) loss event and blocks the link between
the non-ERPS device and ERPS device.
CCMs are propagated by the Connectivity Fault Management (CFM)
protocol as described under "CFM Commands" on page 1309 . If the
standard recovery procedure were used as shown in the following
figure, and node E detected CCM loss, it would send an R-APS (SF)
message to the RPL owner and block the link to node D, isolating that
non-ERPS device.
When non-ERPS device protection is enabled on the ring, the ring ports
on the RPL owner node and non-owner nodes will not be blocked when
signal loss is detected by CCM loss events.
◆ When non-ERPS device protection is enabled on an RPL owner node, it
will send non-standard health-check packets to poll the ring health
when it enters the protection state. It does not use the normal
procedure of waiting to receive an R-APS (NR - no request) message
from nodes adjacent to the recovered link. Instead, it waits to see if the
non-standard health-check packets loop back. If they do, indicating
that the fault has been resolved, the RPL will be blocked.
After blocking the RPL, the owner node will still transmit an R-APS (NR,
RB - ring blocked) message. ERPS-compliant nodes receiving this
message flush their forwarding database and unblock previously
blocked ports. The ring is now returned to Idle state.
non-ERPS
A
non-ERPS
RPL
Owner
RPL
X X
blocked blocked
fault
B C D E F