11 bfd configuration, Introduction to bfd, Bfd configuration – H3C Technologies H3C S7500E Series Switches User Manual
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BFD Configuration
When configuring BFD, go to these sections for information you are interested in:
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Configuring BFD Basic Functions
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Displaying and Maintaining BFD
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The term “router” or router icon in this document refers to a router in a generic sense or an
Ethernet switch running routing protocols.
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The S7500E Series Ethernet Switches are distributed devices supporting Intelligent
Resilient Framework (IRF). Two S7500E series can be connected together to form a
distributed IRF device. If an S7500E series is not in any IRF, it operates as a distributed
device; if the S7500E series is in an IRF, it operates as a distributed IRF device. For
introduction of IRF, see IRF Configuration in the IRF Configuration Guide.
Introduction to BFD
Devices must quickly detect communication failures so that measures can be taken in time to
ensure service continuity and enhance network availability.
Currently, the main fault detection methods include:
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Hardware detection: Detects link failures by sending hardware detection signals, such as
synchronous digital hierarchy (SDH) alarms. Hardware detection can quickly detect link
failures, but not all media types support hardware detection.
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Hello mechanism: Devices can use the hello mechanism of a routing protocol to detect link
failures. The hello mechanism needs seconds to detect a link failure. On a high-speed
interface, such as a Gigabit interface, a failure that lasts for one second will cause a large
quantity of data to be dropped. Therefore, the hello mechanism is unacceptable for
delay-sensitive services such as voice service. Moreover, this detection method largely
relies on the routing protocol.
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Other detection methods: Some protocols provide dedicated detection mechanisms, which
however, cannot be deployed for inter-system communications.
Bidirectional forwarding detection (BFD) provides a single mechanism to monitor links. With
BFD, devices can quickly detect communication failures and restore communications through
backup paths.