Tripp Lite NGI-S08C2POE8, Owner'S Manual

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Wait to restore (WTR) timer -- The RPL owner uses the WTR timer. The WTR timer applies
to the revertive mode to prevent frequent triggering of the protection switching due to port
flapping or intermittent signal failure defects. When this timer expires, the RPL owner sends a
R-APS (NR, RB) through the ring.
Wait to Block (WTB) timers -- This wait-to-block timer is activated on the RPL owner. The
RPL owner uses WTB timers before initiating an RPL block and then reverting to the idle state
after operator-initiated commands, such as for FS or MS conditions, are entered. Because
multiple FS commands are allowed to co-exist in a ring, the WTB timer ensures that the
clearing of a single FS command does not trigger the re-blocking of the RPL. The WTB timer
is defined to be 5 seconds longer than the guard timer, which is enough time to allow a
reporting ERN to transmit two R-APS messages and allow the ring to identify the latent
condition. When clearing a MS command, the WTB timer prevents the formation of a closed
loop due to the RPL owner node applying an outdated remote MS request during the recovery
process.
Hold-off timer -- Each ERN uses a hold-off timer to delay reporting a port failure. When the
timer expires, the ERN checks the port status. If the issue still exists, the failure is reported. If
the issue does not exist, nothing is reported.
ERPS revertive and non-revertive switching
ERPS considers revertive and non-revertive operation. In revertive operation, after the
condition (s) causing a switch has cleared, the traffic channel is restored to the working
transport entity, i.e. blocked on the RPL. In the case of clearing of a defect, the traffic channel
reverts after the expiry of a WTR timer, which is used to avoid toggling protection states in
case of intermittent defects. In non-revertive operation, the traffic channel continues to use the
RPL, if it is not failed, after a switch condition has cleared.
Control VLAN:
The pure ERPS control packets domain only, no other packets are transmitted in this vlan to
guarantee no delay for the ERPS. So when you configure a Control VLAN for a ring, the vlan
should be a new one. The ERPS will create this control vlan and its member ports automatically.
The member port should have the Left and Right ports only.
In ERPS, the control packets and data packets are separated in different vlans.
The control packets are transmitted in a vlan which is called the Control VLAN.
Instance:
For ERPS version 2, the instance is a profile specifies a control vlan and a data vlan or multiple
data vlans for the ERPS. In ERPS, it can separate the control packets and data packets in
different vlans. The control packets are in the Control VLAN and the data packets can be in one
or multiple data vlan. And then user can assign an instance to an ERPS ring easily.
In ERPS version 1, if a port is blocked by ERPS, all packets are blocked.
In ERPS version 2, if a port is blocked by a ring of ERPS, only the packets belong to the vlans
in the instance are blocked.
Notice:
Control VLAN and Instance:
There are the Control VLAN and the Instance settings.
If the Control VLAN is configured for a ring and you want to configure an instance for the ring.