![Huawei Quidway NetEngine40E Configuration Manual - Reliability Download Page 27](http://html.mh-extra.com/html/huawei/quidway-netengine40e/quidway-netengine40e_configuration-manual-reliability_169453027.webp)
With fast detection performed by the OAM, the protection group is listed in the forwarding table
with its primary tunnel entry and bypass tunnel entry. This enables fast switchover after a failure
is detected, providing high reliability for network connectivity.
Figure 1-3
Networking diagram of MPLS OAM protecting switchover
PE2
P3
PE1
P2
P1
MPLS TE
Tunnel
, two TE tunnels are created between the ingress PE1 and egress PE2,
forming a protection group. A TE tunnel is created between PE2 and PE1 through P1 as a reverse
channel, advertising a failure to ingress PE1.
BFD
BFD and OAM are similar because both of them define a set of mechanisms including detection,
failure report, and switchover. For BFD and OAM, the detection is carried out by sending fast
detection packets through a preset path to detect the link status. If the detection packets cannot
pass through the link, the packets are dropped. To avoid the jitters, the number of detection
packets is specified. When the number of the lost detection packets reaches the set value, the
link is considered as interrupted.
BFD is a bidirectional detection mechanism, and its detection packets are sent bidirectionally.
If one end does not receive the detection packets within a specified period, the end assumes that
the link is interrupted and reports to related modules to perform switchover.
HUAWEI NetEngine80E/40E Router
Configuration Guide - Reliability
1 Reliability Overview
Issue 02 (2014-09-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
10