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[EX/QFX] Caveats for ERPS/CFM in ELS switches



Article ID: KB36245 KB Last Updated: 24 Sep 2020Version: 1.0

This article explains Ethernet ring protection switching (ERPS) caveats when it is configured along with Ethernet OAM connectivity fault management (CFM).


ERPS is not reacting to the connectivity fault management (CFM) logical interface when it goes UP/DOWN. However, it does work on Ex2200-Ex3200-EX4500.


‚ÄčThis behavior is the expected due to a hardware limitation.

ELS switches Implement ITU-T G.8032 (ERPS) as implemented in EX4300. On the other hand, CFM and ERPS can work together as needed, in Legacy devices such as EX2200, Ex4200

Additional points to be considered:
Although a switch can be configured for both ERP and STP, there are restrictions in how they can be configured.
  • If ERP is configured on an interface, that interface cannot participate in STP, RSTP or MSTP.
  • If a VLAN is part of an MST instance, it cannot also be in ERP’s control VLAN or data VLANs.
  • The combined total number of ERP instances and MSTP instances or ERP instances alone is limited to 50 instances for EX2300 and 100 instances for EX3400 due to TCAM size.

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