HPE FlexNetwork HSR6800 series Configuration Manual page 11

Technology Introduction
NSR ensures non-stop data transmission during an
active/standby switchover by backing up IP/MPLS forwarding
information from the active MPU to the standby MPU. Upon an
NSR
active/standby switchover, NSR can complete link state recovery
and route re-generation without requiring the cooperation of other
devices. IS-IS supports this feature.
Two devices back up the services of each other to ensure that the
services on them are consistent. If one device fails, the other
device can take over the services by using VRRP or dynamic
Stateful failover
routing protocols. Because the other device has already backed
up the services, service traffic can pass through the other device,
avoiding service interruption.
VRRP is an error-tolerant protocol, which provides highly reliable
VRRP default links on multicast and broadcast LANs such as Ethernet,
avoiding network interruption due to failure of a single link.
4
Reference
Layer 3—IP Routing
Configuration Guide
"Configuring stateful
failover"
"Configuring VRRP"