Reliability Technologies Supported By The Ne80E/40E; Frr (Fast Reroute) - Huawei NetEngine80E Configuration Manual - Reliability

HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability
The protection switching has the following functions:
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1.3 Reliability Technologies Supported by the NE80E/40E

Reliability technologies for IP networks include failure detection technologies and protection
switching technologies.

1.3.1 FRR (Fast ReRoute)

FRR, classified into IP FRR, LDP FRR, MPLS TE FRR, and VPN FRR, is the most common
technology used to perform a fast switchover in case of a failure.
IP FRR
In the forwarding module, an interface status table is created to save information about working
status of every interface on a device. After an abnormality is detected, for example, the physical
link is unavailable or an interface is shut down manually, the interface status table is updated.
In addition, during packet forwarding, if the forwarding table contains load balancing entries,
that is, several next hops, the next hop is selected based on a certain rule and its outgoing interface
is detected in the interface status table. If the outgoing interface of one next hop is invalid, another
next hop is selected and its outgoing interface status is detected until the outgoing interface of
a next hop is valid.
When the last next hop is detected, the packet is forwarded directly without checking the
outgoing interface.
Because detecting and updating the interface status is much faster than route convergence, the
rerouting takes effect faster with the IP FRR technology. Moreover, the load balancing entries
in the forwarding table are checked that ensures highly-reliable forwarding.
The enhanced IP FRR technology supports the next hop of non-equivalence load balancer. An
active next hop is selected by the Interior Gateway Protocol (IGP) and a standby next hop is
configured manually. When a failure occurs, the fast switchover is performed.
LDP FRR
Conventional IP FRR cannot effectively protect traffic on a Multiprotocol Label Switching
(MPLS) network. The NE80E/40E provides MPLS networks with the LDP FRR for protection
at the interface level.
Compared with fast convergence in IGP, the LDP FRR calculates a secondary interface in
advance. Route calculation and re-establishment of an LSP after a failure take less time. As a
result, the switchover speeds up.
Issue 02 (2011-09-10)
Local request protection
Local real-time protection
Processing switchover signal latency
Avoiding single-node switchover
Coexistence and preemption of switchover requests
Switchover recovery mode
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1 Reliability Overview
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