Usage Scenario
- To specify whether to use VCs or NVCs to transmit R-APS PDUs on sub-rings, run the virtual-channel command.
- ERPSv2 supports single and multi-ring topologies.
- In multi-ring topologies, sub-rings either have VCs or NVCs to transmit R-APS PDUs.
- With VCs: R-APS PDUs on sub-rings are transmitted to the major ring through interconnection nodes. The ring protection link (RPL) owner port of a sub-ring blocks both R-APS PDUs and data traffic.
- With NVCs: R-APS PDUs on sub-rings are terminated on the interconnection nodes. The RPL owner port blocks data traffic but not R-APS PDUs on each sub-ring.
Prerequisites
ERPSv2 has been configured using the version v2 command, and the ERPS ring has been configured as a sub-ring using the sub-ring command.
Configuration Impact
If a sub-ring uses VCs to transmit R-APS PDUs, you must run the virtual-channel disable command to restore the R-APS PDU transmission mode to NVC before running the undo sub-ring command to restore the sub-ring to a major ring.
If the VC mode is used for sub-ring R-APS PDU transmission, it is recommended that the major ring's VLAN with an ID same as that of the sub-ring's control VLAN transmit only sub-ring R-APS PDUs. If this major ring's VLAN also transmits data packets, attackers may construct bogus sub-ring R-APS PDUs, causing sub-ring loops or even a major ring failure.