Bfd Configuration; Introduction To Bfd; How Bfd Works - HP 4800G Series Configuration Manual

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BFD Configuration

When configuring BFD, go to these sections for information you are interested in:

Introduction to BFD

BFD Configuration Task List
Configuring BFD Basic Functions
Configuring Protocol-based BFD
Enabling Trap
Displaying and Maintaining BFD
BFD Configuration Examples
The term "router" or router icon in this document refers to a router in a generic sense or an Ethernet
switch running routing protocols.
Introduction to BFD
Bidirectional forwarding detection (BFD) provides a single mechanism to quickly detect and monitor the
connectivity of links in networks. To improve network performance, devices must quickly detect
communication failures to restore communication through backup paths as soon as possible. Normally,
devices in a network may employ the following detection methods:
Detect link failures by sending hardware detection signals, such as SDH (synchronous digital
hierarchy) transmission system alarms.
If no hardware detection signals are provided or failures cannot be detected through hardware
detection signals, devices can use the hello mechanism of a routing protocol for failure detection,
which has a slower failure detection rate of more than one second. In Gigabit data transmission,
such a rate will cause a large quantity of data to be dropped.
Implement real-time detection for all media types and protocols through a uniform mechanism.

How BFD Works

BFD provides a general-purpose, standard, medium- and protocol-independent fast failure detection
mechanism. It can uniformly and quickly detect the failures of the bidirectional forwarding paths
between two routers for protocols, such as routing protocols and Multiprotocol Label Switching (MPLS).
BFD provides no neighbor discovery mechanism. Protocols that BFD services notify BFD of routers to
which it needs to establish sessions. After a session is established, if no BFD control packet is received
from the peer within the negotiated BFD interval, BFD notifies a failure to the protocol, which takes
appropriate measures.
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