High- availability features include Routing
Engine redundancy, graceful Routing Engine switchover (GRES), nonstop
bridging, nonstop active routing, graceful restart for routing protocols,
Virtual Router Redundancy Protocol (VRRP), and unified in-service
software upgrade (ISSU). Some high-availability features are not supported
by all platforms and all PICs. For information about the first supported
Junos OS release for these features by PIC and platform, see the Junos OS High Availability Configuration Guide
.