H3C Technologies H3C S10500 Series Switches - Manual (Page 13)

4
Technology Introduction Reference
FRR
Fast Reroute (FRR) provides a quick per-link or per-node protection
on an LSP. In this approach, once a link or node fails on a path, FRR
comes up to reroute the path to a new link or node to bypass the
failed link or node. This can happen as fast as 50 milliseconds
minimizing data loss. Protocols such as RIP, OSPF, IS-IS, static
routing, and RSVP-TE support this technology.
Layer 3—IP Routing
Configuration Guide,
MPLS Configuration
Guide/Configuration
Guide of the
corresponding
protocols
GR
Graceful Restart (GR) ensures the continuity of packet forwarding
when a protocol, such as BGP, IS-IS, OSPF, IPv6 BGP, IPv6 IS-IS,
OSPFv3, LDP, or RSVP-TE, restarts or during an active/standby
switchover process. It needs other devices to implement routing
information backup and recovery.
Layer 3—IP Routing
Configuration Guide,
MPLS Configuration
Guide/Configuration
Guide of the
corresponding
protocols
NSR
Non-stop Routing (NSR) is a new feature used to ensure non-stop
data transmission during an active/standby switchover. It backs up
IP forwarding information from the active MPU to the standby MPU.
Upon an active/standby switchover, NSR can complete link state
recovery and route re-generation without requiring the cooperation
of other devices. OSPF supports this feature.
OSPF configuration in
the Layer 3—IP
Routing Configuration
Guide
VRRP
Virtual Router Redundancy Protocol (VRRP) is an error-tolerant
protocol that provides highly reliable default links on multicast and
broadcast LANs such as Ethernet, avoiding network interruption
due to failure of a single link.
VRRP configuration in
the High Availability
Configuration Guide
A single availability technology cannot solve all problems. Therefore, a combination of availability
technologies, chosen on the basis of detailed analysis of network environments and user requirements,
should be used to enhance network availability. For example, access-layer devices should be connected
to distribution-layer devices over redundant links, and core-layer devices should be fully meshed. Also,
network availability should be considered during planning prior to building a network.