NSR and Unified ISSU Support for EVPN VPWS and PBB EVPN

Junos OS supports NSR and Unified ISSU on VPWS with EVPN and provider backbone bridging (PBB) EVPN. NSR and GRES enables the routing system to switch over from a primary Routing Engine to a backup Routing Engine while continuing to forward packets. Unified ISSU enables you to upgrade between two different Junos OS releases with no disruption on the control plane and with minimal disruption of traffic. Unified ISSU upgrade is only supported by dual Routing Engine platforms. Unified ISSU requires both GRES and NSR to be enabled. To enable GRES, include the graceful-switchover statement at the [edit chassis redundancy] hierarchy level. To enable NSR, include the nonstop-routing statement at the [edit routing-options] hierarchy level and the commit synchronize statement at the [edit system] hierarchy level.