API Guide

● For the S4100-ON series platform, you configure a BFD interval of 500 ms with multiplier of 3 or higher for
multidimensional scaled configurations.
● For other series switches, you configure a BFD interval of 200 ms with a multiplier of 4 or higher for multidimensional
scaled configurations.
Configure BFD globally
Before you configure BFD for static routing or a routing protocol, configure BFD globally on each router, including the global
BFD session settings. BFD is disabled by default.
1. Configure the global BFD session parameters in CONFIGURATION mode.
bfd interval milliseconds min_rx milliseconds multiplier number role {active |
passive}
● interval milliseconds — Enter the time interval for sending control packets to BFD peers, from 100 to 1000. The
default is 200. Dell EMC recommends using more than 100 milliseconds.
● min_rx milliseconds — Enter the maximum waiting time for receiving control packets from BFD peers, from 100 to
1000. The is default 200. Dell EMC recommends using more than 100 milliseconds.
● multiplier number — Enter the number of consecutive packets that must not be received from a BFD peer before
the session state changes to Down, from 3 to 50. The default is 3.
● role {active | passive} — Enter active if the router initiates BFD sessions. Both BFD peers can be active at
the same time. Enter passive if the router does not initiate BFD sessions, and only responds to a request from an
active BFD to initialize a session. The default is active.
2. Enable BFD globally in CONFIGURATION mode.
bfd enable
To verify that BFD is globally enabled, use the show running-config bfd command.
BFD global configuration
OS10(config)# bfd interval 250 min_rx 300 multiplier 4 role passive
OS10(config)# bfd enable
OS10(config)# do show running-config bfd
!
bfd enable
bfd interval 250 min_rx 300 multiplier 4 role passive
View information about active BFD neighbors
OS10#show bfd neighbors active
* - Active session role
-----------------------------------------------------------------------------------------
--
LocalAddr RemoteAddr Interface State RxInt TxInt Mult VRF
Clients
-----------------------------------------------------------------------------------------
--
* 100.100.1.1 100.100.1.2 ethernet1/1/26:1 up 200 200 3 red ospfv2
* 100.100.3.1 100.100.3.2 ethernet1/1/26:3 up 200 200 3 default ospfv2
* 200.1.1.2 200.1.1.1 vlan102 up 200 200 3 black bgp
* 200.1.5.2 200.1.5.1 vlan105 up 200 200 3 default ospfv2
* 200.1.11.2 200.1.11.1 vlan111 up 200 200 3 green rtmv4
* 200.1.12.2 200.1.12.1 vlan112 up 200 200 3 default rtmv4
* 201.1.1.2 201.1.1.1 vlan101 up 200 200 3 green ospfv2
BFD for BGP
In a BGP core network, BFD enables faster network reconvergence. BFD rapidly detects communication failures in BGP fast-
forwarding paths between internal BGP (iBGP) and external BGP (eBGP) peers. BFD for BGP is supported on physical, port-
channel, and VLAN interfaces. BFD for BGP does not support the BGP multihop feature.
Layer 3
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