Alcatel-Lucent 6850-48 Guida Di Rete
OmniSwitch AOS Release 6 Network Configuration Guide
September 2009
page 30-1
30 Configuring BFD
An increasingly important requirement of networking equipment is to rapidly detect communication fail-
ures between network systems to quickly establish alternative paths and reduce network convergence time.
When data link hardware such as SONET alarms are present, failure detection can be fairly easy and
quick. However, some media, such as Ethernet, do not support such kind of signaling, and some media
may not detect certain kinds of failures in the path, such as failing interfaces or forwarding engine compo-
nents.
ures between network systems to quickly establish alternative paths and reduce network convergence time.
When data link hardware such as SONET alarms are present, failure detection can be fairly easy and
quick. However, some media, such as Ethernet, do not support such kind of signaling, and some media
may not detect certain kinds of failures in the path, such as failing interfaces or forwarding engine compo-
nents.
In the absence of such signaling hardware, networks resort to using simple “Hello” mechanisms to detect
failures in the communication pathways between adjacent systems. One such mechanism is the Bidirec-
tional Forwarding Detection (BFD) protocol.
failures in the communication pathways between adjacent systems. One such mechanism is the Bidirec-
tional Forwarding Detection (BFD) protocol.
BFD protocol is a fairly simple and quick Hello protocol; it can be configured in the interfaces and with
routing protocols to rapidly detect faults in the bidirectional paths between adjacent forwarding engines,
including interfaces, data link(s), and even the forwarding engines themselves. BFD is not intended to
directly control liveliness information; instead, the application provides parameters and BFD supplies the
state of the session. It acts in an advisory role to the control protocols, and provides a low overhead alter-
native to detect faults for all media types, encapsulations, and routing protocols in a variety of network
environments and topologies.
routing protocols to rapidly detect faults in the bidirectional paths between adjacent forwarding engines,
including interfaces, data link(s), and even the forwarding engines themselves. BFD is not intended to
directly control liveliness information; instead, the application provides parameters and BFD supplies the
state of the session. It acts in an advisory role to the control protocols, and provides a low overhead alter-
native to detect faults for all media types, encapsulations, and routing protocols in a variety of network
environments and topologies.
In This Chapter
This chapter describes the basic components of BFD and how to configure them through the Command
Line Interface (CLI). CLI commands are used in the configuration examples; for more details about the
syntax of commands, see the Omniswitch CLI Reference Guide.
Line Interface (CLI). CLI commands are used in the configuration examples; for more details about the
syntax of commands, see the Omniswitch CLI Reference Guide.
Configuration procedures described in this chapter include:
• Global Configuration (see
• Interface Level Configuration (see
).
• OSPF level configuration (see
).
• BGP Level Configuration (see
).
• VRRP Level Configuration (see
).
• Static Routing Level Configuration (see
).