The protecting node must use CPM-4 or higher (other protected nodes can continue to use CPM-3).
The protecting node functionality is not supported in the 7450 ESS chassis.
All nodes in the OMCR cluster (central standby and the protected nodes) must run at the minimum SR OS Release 12.0R1.
Warm-standby mode is a chassis-wide property. In other words, while in warm-standby mode, the chassis cannot operate in 1:1 (active-active) redundancy mode.
OMCR is supported only for IPoEv4/v6 subscribers. However, non-synchronized PPPoEv4/v6 subscribers are supported in the OMCR cluster. PPPoEv4/v6 PTA (locally terminated) non-synchronized subscribers and the OMCR synchronized IPoE subscriber must be instantiated under separate group-interfaces. On the other hand, non-synchronized PPPoEv4/v6 LAC sessions can be under the same group interface as the OMCR synchronized IPoE subscribers. Non-synchronized PPPoEv4/v6 subscriber hosts rely on ppp-keepalive timeouts to re-establish connectivity when the failure occurs.
Preemption of already instantiated subscriber hosts in the protecting node by another subscriber hosts is not allowed.
Redundant interface (shunting) is not supported for subscribers on the protecting node while they are not fully instantiated in the control/data plane (or while the underlying SRRP instance is in a non-master state on the protecting node).
Persistency in multi-chassis environment must be disabled because redundant nodes are protecting each other and they maintain up-to-date lease states.
The failover trigger is based on SRRP only (no MC-LAG support).
Unnumbered subscriber-interface model is not supported in OMCR.
The protecting node supports 10 MCS peers, while the protected node (in active/active mode of operation) supports 4 MCS peers.
Synchronization of the following MCS clients is not supported:
Host tracking
MC ring
Layer 2 subscriber hosts
Layer 3 IGMP/MLD
Layer 2 IGMP/MLD
DHCP Server
PPPoE Clients
MC-LAG
MC-IPSEC
MC-ENDPOINT