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Enhanced
Interior Gateway Routing Protocol (EIGRP) must be running on all participating
routers.
The baseline
parameters for Bidirectional Forwarding Detection (BFD) sessions on the
interfaces over which you want to run BFD sessions to BFD neighbors must be
configured using the
bfd command.
Information About BFD-EIGRP Support
The BFD-EIGRP Support feature configures Bidirectional Forwarding Detection (BFD) feature for Enhanced Interior Gateway Routing
Protocol (EIGRP) so that EIGRP registers with the BFD sessions on the routing interfaces, and receives forwarding path detection
failure messages from BFD.
Use bfd intervalmillisecondsmin_rxmillisecondsmultiplierinterval-multiplier command to enable BFD on any interface. Use the bfd all-interfaces command in router configuration mode to enable BFD for all of the interfaces where EIGRP routing is enabled. Use the bfd interfacetype number command in router configuration mode to enable BFD for a subset of the interfaces where EIGRP routing is enabled.
Configuring BFD - EIGRP
Support
Procedure
Command or Action
Purpose
Step 1
enable
Example:
Device>enable
Enables privileged EXEC mode.
Enter your password if prompted.
Step 2
configureterminal
Example:
Device#configure terminal
Enters global configuration mode.
Step 3
routereigrpas-number
Example:
Device(config)#router eigrp 123
Configures the EIGRP routing process and enters router configuration mode.
(Optional) Displays the interfaces for which BFD support for EIGRP has been enabled.
Configuration Example for BFD in an EIGRP Network with Echo Mode Enabled by Default
In the following example, the EIGRP network contains DeviceA, DeviceB, and DeviceC. Fast Ethernet interface 1/0 on DeviceA
is connected to the same network as Fast Ethernet interface 1/0 on DeviceB. Fast Ethernet interface 1/0 on DeviceB is connected
to the same network as Fast Ethernet interface 1/0 on DeviceC.
DeviceA and DeviceB are running BFD Version 1, which supports echo mode, and DeviceC is running BFD Version 0, which does
not support echo mode. The BFD sessions between DeviceC and its BFD neighbors are said to be running echo mode with asymmetry
because echo mode will run on the forwarding path for DeviceA and DeviceB, and their echo packets will return along the same
path for BFD sessions and failure detections, while their BFD neighbor DeviceC runs BFD Version 0 and uses BFD controls packets
for BFD sessions and failure detections.
The figure below shows a large EIGRP network with several devices, three of which are BFD neighbors that are running EIGRP
as their routing protocol.
The example, starting in global configuration mode, shows the configuration of BFD.
Configuration for DeviceA
interface Fast Ethernet0/0
no shutdown
ip address 10.4.9.14 255.255.255.0
duplex auto
speed auto
!
interface Fast Ethernet1/0
ip address 172.16.1.1 255.255.255.0
bfd interval 50 min_rx 50 multiplier 3
no shutdown
duplex auto
speed auto
!
router eigrp 11
network 172.16.0.0
bfd all-interfaces
auto-summary
!
ip default-gateway 10.4.9.1
ip default-network 0.0.0.0
ip route 0.0.0.0 0.0.0.0 10.4.9.1
ip route 172.16.1.129 255.255.255.255 10.4.9.1
!
no ip http server
!
logging alarm informational
!
control-plane
!
line con 0
exec-timeout 30 0
stopbits 1
line aux 0
stopbits 1
line vty 0 4
login
!
!
end
Configuration for DeviceB
!
interface Fast Ethernet0/0
no shutdown
ip address 10.4.9.34 255.255.255.0
duplex auto
speed auto
!
interface Fast Ethernet1/0
ip address 172.16.1.2 255.255.255.0
bfd interval 50 min_rx 50 multiplier 3
no shtdown
duplex auto
speed auto
!
router eigrp 11
network 172.16.0.0
bfd all-interfaces
auto-summary
!
ip default-gateway 10.4.9.1
ip default-network 0.0.0.0
ip route 0.0.0.0 0.0.0.0 10.4.9.1
ip route 172.16.1.129 255.255.255.255 10.4.9.1
!
no ip http server
!
logging alarm informational
!
control-plane
!
line con 0
exec-timeout 30 0
stopbits 1
line aux 0
stopbits 1
line vty 0 4
login
!
!
end
Configuration for DeviceC
!
!
interface Fast Ethernet0/0
no shutdown
ip address 10.4.9.34 255.255.255.0
duplex auto
speed auto
!
interface Fast Ethernet1/0
ip address 172.16.1.2 255.255.255.0
bfd interval 50 min_rx 50 multiplier 3
no shutdown
duplex auto
speed auto
!
router eigrp 11
network 172.16.0.0
bfd all-interfaces
auto-summary
!
ip default-gateway 10.4.9.1
ip default-network 0.0.0.0
ip route 0.0.0.0 0.0.0.0 10.4.9.1
ip route 172.16.1.129 255.255.255.255 10.4.9.1
!
no ip http server
!
logging alarm informational
!
control-plane
!
line con 0
exec-timeout 30 0
stopbits 1
line aux 0
stopbits 1
line vty 0 4
login
!
!
end
The output from the showbfdneighborsdetails command from DeviceA verifies that BFD sessions are created among all three devices and that EIGRP is registered for BFD
support. The first group of output shows that DeviceC with the IP address 172.16.1.3 runs BFD Version 0 and therefore does
not use the echo mode. The second group of output shows that DeviceB with the IP address 172.16.1.2 runs BFD Version 1, and
the 50 millisecond BFD interval parameter had been adopted. The relevant command output is shown in bold in the output.
DeviceA# show bfd neighbors detailsOurAddrNeighAddr
LD/RD RH/RS Holdown(mult) State Int
172.16.1.1 172.16.1.3
5/3 1(RH) 150 (3 ) Up Fa1/0
Session state is UP and not using echo function.
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 50000, MinRxInt: 50000, Multiplier: 3
Received MinRxInt: 50000, Received Multiplier: 3
Holdown (hits): 150(0), Hello (hits): 50(1364284)
Rx Count: 1351813, Rx Interval (ms) min/max/avg: 28/64/49 last: 4 ms ago
Tx Count: 1364289, Tx Interval (ms) min/max/avg: 40/68/49 last: 32 ms ago
Registered protocols: EIGRP
Uptime: 18:42:45
Last packet: Version: 0
- Diagnostic: 0
I Hear You bit: 1 - Demand bit: 0
Poll bit: 0 - Final bit: 0
Multiplier: 3 - Length: 24
My Discr.: 3 - Your Discr.: 5
Min tx interval: 50000 - Min rx interval: 50000
Min Echo interval: 0
OurAddr NeighAddr
LD/RD RH/RS Holdown(mult) State Int
172.16.1.1 172.16.1.2
6/1 Up 0 (3 ) Up Fa1/0
Session state is UP and using echo function with 50 ms interval.
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3
Received MinRxInt: 1000000, Received Multiplier: 3
Holdown (hits): 3000(0), Hello (hits): 1000(317)
Rx Count: 305, Rx Interval (ms) min/max/avg: 1/1016/887 last: 448 ms ago
Tx Count: 319, Tx Interval (ms) min/max/avg: 1/1008/880 last: 532 ms ago
Registered protocols: EIGRP
Uptime: 00:04:30
Last packet: Version: 1
- Diagnostic: 0
State bit: Up - Demand bit: 0
Poll bit: 0 - Final bit: 0
Multiplier: 3 - Length: 24
My Discr.: 1 - Your Discr.: 6
Min tx interval: 1000000 - Min rx interval: 1000000
Min Echo interval: 50000
The output from the showbfdneighborsdetails command on DeviceB verifies that BFD sessions have been created and that EIGRP is registered for BFD support. As previously
noted, DeviceA runs BFD Version 1, therefore echo mode is running, and DeviceC runs BFD Version 0, so echo mode does not run.
The relevant command output is shown in bold in the output.
DeviceB# show bfd neighbors details OurAddr NeighAddr
LD/RD RH/RS Holdown(mult) State Int
172.16.1.2 172.16.1.1
1/6 Up 0 (3 ) Up Fa1/0
Session state is UP and using echo function with 50 ms interval.
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3
Received MinRxInt: 1000000, Received Multiplier: 3
Holdown (hits): 3000(0), Hello (hits): 1000(337)
Rx Count: 341, Rx Interval (ms) min/max/avg: 1/1008/882 last: 364 ms ago
Tx Count: 339, Tx Interval (ms) min/max/avg: 1/1016/886 last: 632 ms ago
Registered protocols: EIGRP
Uptime: 00:05:00
Last packet: Version: 1
- Diagnostic: 0
State bit: Up - Demand bit: 0
Poll bit: 0 - Final bit: 0
Multiplier: 3 - Length: 24
My Discr.: 6 - Your Discr.: 1
Min tx interval: 1000000 - Min rx interval: 1000000
Min Echo interval: 50000
OurAddr NeighAddr
LD/RD RH/RS Holdown(mult) State Int
172.16.1.2 172.16.1.3
3/6 1(RH) 118 (3 ) Up Fa1/0
Session state is UP and not using echo function.
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 50000, MinRxInt: 50000, Multiplier: 3
Received MinRxInt: 50000, Received Multiplier: 3
Holdown (hits): 150(0), Hello (hits): 50(5735)
Rx Count: 5731, Rx Interval (ms) min/max/avg: 32/72/49 last: 32 ms ago
Tx Count: 5740, Tx Interval (ms) min/max/avg: 40/64/50 last: 44 ms ago
Registered protocols: EIGRP
Uptime: 00:04:45
Last packet: Version: 0
- Diagnostic: 0
I Hear You bit: 1 - Demand bit: 0
Poll bit: 0 - Final bit: 0
Multiplier: 3 - Length: 24
My Discr.: 6 - Your Discr.: 3
Min tx interval: 50000 - Min rx interval: 50000
Min Echo interval: 0
The figure below shows that Fast Ethernet interface 1/0 on DeviceB has failed. When Fast Ethernet interface 1/0 on DeviceB
is shut down, the BFD statistics of the corresponding BFD sessions on DeviceA and DeviceB are reduced.
When Fast Ethernet interface 1/0 on DeviceB fails, BFD will no longer detect DeviceB as a BFD neighbor for DeviceA or for
DeviceC. In this example, Fast Ethernet interface 1/0 has been administratively shut down on DeviceB.
The following output from the showbfdneighbors command on DeviceA now shows only one BFD neighbor for DeviceA in the EIGRP network. The relevant command output is shown
in bold in the output.
DeviceA# show bfd neighborsOurAddr NeighAddr
LD/RD RH/RS Holdown(mult) State Int
172.16.1.1 172.16.1.3
5/3 1(RH) 134 (3 ) Up Fa1/0
The following output from the showbfdneighbors command on DeviceC also now shows only one BFD neighbor for DeviceC in the EIGRP network. The relevant command output is
shown in bold in the output.
DeviceC# show bfd neighborsOurAddr NeighAddr
LD/RD RH Holdown(mult) State Int
172.16.1.3 172.16.1.1
3/5 1 114 (3 ) Up Fa1/0
Feature History for Configuring BFD-EIGRP Support
This table provides release and related information for the features explained in
this module.
These features are available in all the releases subsequent to the one they were
introduced in, unless noted otherwise.
Release
Feature
Feature Information
Cisco IOS XE Fuji 16.9.2
BFD-EIGRP Support
The BFD-EIGRP Support feature configures the EIGRP with BFD so
that EIGRP registers with BFD and receives all forwarding path
detection failure messages from BFD.
Use the Cisco Feature Navigator to find information about platform and software image
support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn.