Overview of NSR
Definition
After Non-Stop Routing (NSR) is configured on a local device with active and standby MPUs installed, the control plane of its neighbor cannot detect the fault occurring on the local device's control plane. Therefore, the key of NSR is that the control plane failover is independent of neighbors.
Purpose
The demand for data, audio, and video services is growing, which imposes increasing requirements on IP network reliability. A provider edge (PE) can perform a switchover of active and standby MPUs if a single point of failure occurs or a maintenance operation (an upgrade, for example) is performed. The PE fails to converge routing information during a switchover of active and standby MPUs if its neighbor nodes fail simultaneously or these nodes do not support graceful restart (GR). NSR helps the PE converge routing information and ensures uninterrupted forwarding.
Benefits
NSR prevents route flapping during a switchover of active and standby MPUs so that services are not affected. NSR satisfies user requirements for high IP network reliability.
Protocols That Can Be Used with NSR on the Switch
Eth-Trunk
E-Trunk
IS-IS
OSPF
OSPFv3
BGP
BGP4+
PIM
MSDP
MVPN
IPv4/IPv6 L3VPN
RSVP
LDP
BFD
VRRP