D-Link DGS-3120-24PC Manual page 288

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xStack DGS-3120 Series Layer 2 Managed Stackable Gigabit Switch CLI Reference Guide
30-5 config erps raps_vlan
Description
This command is used to configure the ERPS R-APS VLAN settings.
The ring MEL is one field in the R-APS PDU. Note that if CFM (Connectivity Fault Management)
and ERPS are used at the same time, the R-APS PDU is one of a suite of Ethernet OAM PDU.
The behavior for forwarding of R-APS PDU should follow the Ethernet OAM. If the MEL of R-APS
PDU is not higher than the level of the MEP with the same VLAN on the ring ports, the R-APS
PDU cannot be forwarded on the ring.
Restrictions apply for ports that are included in a link aggregation group. A link aggregation group
can be configured as a ring port by specifying the master port of the link aggregation port. Only the
master port can be specified as a ring port. If the specified link aggregation group is eliminated, the
master port retains its ring port status. If the ring port configured on virtual channel, the ring which
the port connects to will be considered as a sub-ring. Note that the ring ports can be modified
when ERPS is enabled.
RPL port - Specify one of the R-APS VLAN ring ports as the RPL port. To remove an RPL port
from an R-APS VLAN, use the none designation for rpl_port.
RPL owner - Specify the node as the RPL owner.
Note that the RPL port and RPL owner can be modified when ERPS is enabled; and the virtual
channel cannot be configured as RPL. For example, if a ring port is configured on the virtual
channel and the ring port is configured as an RPL port, an error message will be display and the
configuration will fail.
The R-APS VLAN cannot be the protected VLAN. The protected VLAN can be one that has
already been created, or it can be used for a VLAN that has not yet been created.
Holdoff timer - The Holdoff timer is used to filter out intermittent link faults when link failures occur
during the protection switching process. When a ring node detects a link failure, it will start the
holdoff timer and report the link failure event (R-APS BPDU with SF flag) after the link failure is
confirmed within period of time specified.
Guard timer - Guard timer is used to prevent ring nodes from receiving outdated R-APS
messages. This timer is used during the protection switching process after the link failure recovers.
When the link node detects the recovery of the link, it will report the link failure recovery event (R-
APS PDU with NR flag) and start the guard timer. Before the guard timer expires, all received R-
APS messages are ignored by this ring node, except in the case where a burst of three R-APS
event messages that indicates the topology of a sub-ring has changed and the node needs to flush
FDB are received on the node. In this case the recovered link does not go into a blocking state.
The Guard Timer should be greater than the maximum expected forwarding delay for which one R-
APS message circles around the ring.
WTR timer - WTR timer is used to prevent frequent operation of the protection switch due to an
intermittent defect. This timer is used during the protection switching process when a link failure
recovers. It is only used by the RPL owner. When the RPL owner in protection state receives R-
APS PDU with an NR flag, it will start the WTR timer. The RPL owner will block the original
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