(Optional) Enabling Enhanced M-LAG Layer 3 Forwarding
Context
To speed up convergence when an M-LAG member interface fails, you can enable enhanced M-LAG Layer 3 forwarding so that backup FRR resources are requested for all ARP and ND entries with M-LAG member interfaces as outbound interfaces. Active and standby paths are established for traffic forwarding on downlink outbound interfaces. If an M-LAG member interface fails, the outbound interface can be quickly changed to a peer-link interface.
CE12800 switches (configured with FD1, FG, FG1, SD, FD and FDA series cards) support enhanced M-LAG Layer 3 forwarding in IPv4 and IPv6 scenarios.
CE12800E switches support enhanced M-LAG Layer 3 forwarding in IPv4 and IPv6 scenarios.
Procedure
- Run system-view
The system view is displayed.
- Run m-lag forward layer-3 enhanced enable
Enhanced M-LAG Layer 3 forwarding is enabled.
By default, enhanced M-LAG Layer 3 forwarding is disabled.
After enhanced M-LAG Layer 3 forwarding is enabled, backup FRR resources are requested for all ARP and ND entries with M-LAG member interfaces as outbound interfaces. The outbound interfaces can be changed to peer-link interfaces to establish active and standby paths for traffic forwarding. If the FEI side detects that an M-LAG member interface fails, dual-homing networking is changed to single-homing networking. The next hop in the corresponding ARP or ND entry is changed from the M-LAG member interface to the peer-link interface. This improves the switchover performance when faults occur.
- After enhanced M-LAG Layer 3 forwarding is enabled, the active and standby paths may fail to be delivered due to increased next-hop resource consumption. As a result, packet loss occurs.
- After enhanced M-LAG Layer 3 forwarding is enabled, you need to configure an Eth-Trunk interface to clear all the learned ARP and ND entries when the Eth-Trunk joining in or being removed from M-LAG. This prevents the upper-layer protocol module from detecting the waste of FRR resources caused by the change of M-LAG member interfaces.
- After enhanced M-LAG Layer 3 forwarding is enabled, you can disable this function only after 300s. After enhanced M-LAG Layer 3 forwarding is disabled, you can enable this function only after 300s.
- You can configure this command in the Admin-VS only, and the configuration takes effect for the entire device.
- Run commit
The configuration is committed.