Use graceful Routing Engine switchover (GRES) and nonstop active routing (NSR) to prevent traffic loss in EVPN-VXLAN environment

The graceful Routing Engine switchover (GRES) feature enables a Juniper Networks device to continue forwarding packets, even if one Routing Engine fails. To preserve routing during a switchover, GRES is combined with nonstop active routing (NSR). Although GRES preserves interface and kernel information, in an EVPN/VXLAN environment, a Juniper Networks device could experience Layer 3 traffic loss if traffic is flowing during the switchover or reboot of the Routing Engine. To prevent traffic flows from being dropped in such a scenario, configure a hold-time interval that prevents IP phantom addresses from being added to the routing tables.