H3C Technologies H3C S12500 Series Switches - Manual (Page 15)

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 thus
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, and
Configuration Guide
of the corresponding
protocols
GR
Graceful Restart (GR) prevents forwarding discontinuity caused by
a protocol restart (including a BGP, IS-IS, OSPF, LDP, or RSVP-TE
restart) or an active/standby switchover. This feature requires the
peer devices to implement routing information backup and
recovery.
Layer 3—IP Routing
Configuration Guide,
MPLS Configuration
Guide, and
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/MPLS 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. IS-IS supports this
feature.
Layer 3—IP Routing
Configuration Guide
VRRP
Virtual Router Redundancy Protocol (VRRP) is an error-tolerant
protocol, which provides highly reliable default links on multicast
and broadcast LANs such as Ethernet, avoiding network
interruption due to failure of a single link.
"Configuring VRRP"
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.