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 is 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:
In CLI or Web configurations, 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. The control vlan of the instance must be same as the Control VLAN; otherwise, you
will get an error. If you still want to use this instance, you can change the Control VLAN
to same as the control vlan of the instance first. And then configures the instance.
CLI Configuration