Bidirectional Forwarding Detection |
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Bidirectional Forwarding Detection
Bidirectional Forwarding Detection
is supported only on platforms:
c e
BFD is supported on E-Series ExaScale
e
x
with FTOS 8.2.1.0 and later.
Protocol Overview
Bidirectional Forwarding Detection (BFD) is a protocol that is used to rapidly detect communication
failures between two adjacent systems. It is a simple and lightweight replacement for existing routing
protocol link state detection mechanisms. It also provides a failure detection solution for links on which no
routing protocol is used.
BFD is a simple hello mechanism. Two neighboring systems running BFD establish a session using a
three-way handshake. After the session has been established, the systems exchange periodic control
packets at sub-second intervals. If a system does not receive a hello packet within a specified amount of
time, routing protocols are notified that the forwarding path is down.
BFD provides forwarding path failure detection times on the order of milliseconds rather than seconds as
with conventional routing protocol hellos. It is independent of routing protocols, and as such provides a
consistent method of failure detection when used across a network. Networks converge faster because BFD
triggers link state changes in the routing protocol sooner and more consistently, because BFD can
eliminate the use of multiple protocol-dependent timers and methods.
BFD also carries less overhead than routing protocol hello mechanisms. Control packets can be
encapsulated in any form that is convenient, and, on Dell Force10 routers, sessions are maintained by BFD
Agents that reside on the line card, which frees resources on the RPM. Only session state changes are
reported to the BFD Manager (on the RPM), which in turn notifies the routing protocols that are registered
with it.
BFD is an independent and generic protocol, which all media, topologies, and routing protocols can
support using any encapsulation. Dell Force10 has implemented BFD at Layer 3 and with UDP
encapsulation. BFD functionality will be implemented in phases. OSPF, IS-IS (not on C-Series), VRRP,
VLANs, LAGs, static routes, and physical ports support BFD, based on the IETF internet draft
draft-ietf-bfd-base-03
.
Summary of Contents for Force10 E300
Page 1: ...FTOS Configuration Guide FTOS 8 4 2 7 E Series TeraScale C Series S Series S50 S25 ...
Page 32: ...32 w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 132: ...132 802 1X w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 310: ...310 Configuration Replace and Rollback w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 330: ...330 Dynamic Host Configuration Protocol w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 402: ...402 High Availability w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 462: ...462 Interfaces w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 482: ...482 IPv4 Addressing w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 506: ...506 IPv6 Addressing w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 582: ...582 Layer 2 w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 642: ...642 Multicast Source Discovery Protocol w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 662: ...662 Multiple Spanning Tree Protocol w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 690: ...690 Object Tracking w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 754: ...754 PIM Dense Mode w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 784: ...784 PIM Source Specific Mode w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 800: ...800 Power over Ethernet w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 876: ...876 Quality of Service w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 892: ...892 Routing Information Protocol w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 1006: ...1006 Simple Network Management Protocol w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 1018: ...1018 SONET SDH w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 1048: ...1048 Broadcast Storm Control w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 1096: ...1096 Uplink Failure Detection UFD w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 1098: ...1098 Upgrade Procedures w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 1196: ...1196 C Series Debugging and Diagnostics w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 1252: ...1252 Standards Compliance w w w d e l l c o m s u p p o r t d e l l c o m ...
Page 1262: ...1262 Index w w w d e l l c o m s u p p o r t d e l l c o m ...