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Bidirectional Forwarding Detection
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Two important parameters are calculated using the values contained in the control packet.
•
Transmit interval —
Transmit interval
is the agreed-upon rate at which a system sends control
packets. Each system has its own transmit interval, which is the greater of the last received remote
Desired TX Interval and the local Required Min RX Interval.
•
Detection time —
Detection time is the amount of time that a system does not receive a control
packet, after which the system determines that the session has failed. Each system has its own
detection time.
•
In Asynchronous mode: Detection time is the remote Detection Multiplier multiplied by greater of
the remote Desired TX Interval and the local Required Min RX Interval.
•
In Demand mode: Detection time is the local Detection Multiplier multiplied by the greater of the
local Desired Min TX and the remote Required Min RX Interval.
Table 9-1. BFD Packet Fields
Field
Description
Diagnostic Code
The reason that the last session failed.
State
The current local session state. See
BFD sessions
.
Flag
A bit that indicates packet function. If the poll bit is set, the receiving system must respond as
soon as possible, without regard to its transmit interval. The responding system clears the poll
bit and sets the final bit in its response. The poll and final bits are used during the handshake
and Demand mode (see
BFD sessions
).
Note:
FTOS does not currently support multi-point sessions, Demand mode,
authentication, or control plane independence; these bits are always clear.
Detection Multiplier
The number of packets that must be missed in order to declare a session down.
Length
The entire length of the BFD packet.
My Discriminator
A random number generated by the local system to identify the session.
Your Discriminator
A random number generated by the remote system to identify the session. Discriminator
values are necessary to identify the session to which a control packet belongs since there can
be many sessions running on a single interface.
Desired Min TX Interval
The minimum rate at which the local system would like to send control packets to the remote
system.
Required Min RX Interval
The minimum rate at which the local system would like to receive control packets from the
remote system.
Required Min Echo RX
The minimum rate at which the local system would like to receive echo packets.
Note:
FTOS does not currently support the echo function.
Authentication Type
An optional method for authenticating control packets.
Note:
FTOS does not currently support the BFD authentication function.
Authentication Length
Authentication Data
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 ...