Note
No license is required for BFD features.
BFD has the following configuration limitations:
NX-OS supports BFD version 1.
BFD supports single-hop BFD; BFD for BGP supports single-hop EBGP and iBGP peers.
BFD depends on Layer 3 adjacency information to discover topology changes, including Layer 2 topology changes. A BFD session on a VLAN interface (SVI) may not be up after the convergence of the Layer 2 topology if no Layer 3 adjacency information is available.
For port channels used by BFD, you must enable the Link Aggregation Control Protocol (LACP) on the port channel.
HSRP for IPv4 is supported with BFD. HSRP for IPv6 is not supported with BFD.
Tables 1-15 through 1-18 described the most-used BFD configuration commands. For a full list of the commands, refer to the Nexus Unicast Routing Configuration Guide in the reference section at the end of the chapter.
Table 1-15 BFD Global-Level Configurations
Table 1-16 BFD Routing-Level Configurations
Table 1-17 BFD Interface-Level Command
Table 1-18 BFD Verification Commands
Figure 1-8 shows the network topology for the configuration that follows, which demonstrates how to configure Nexus BFD for OSPFv2.
Figure 1-8 BFD Network Topology
Example 1-15 shows the SW9621-1 BFD feature enabling and its configuration.
Example 1-15 SW9621-1 BFD Configuration
SW9621-1(config)#
feature bfd
SW9621-1(config)#
interface Ethernet2/3
SW9621-1(config-if)#
ip ospf bfd
SW9621-1(config-if)#
no ip redirects
SW9621-1(config-if)#
no ipv6 redirects
SW9621-1(config-if)#
bfd interval 100 min_rx 100 multiplier 5
Example 1-16 shows SW9621-1 BFD neighbors.
Example 1-16 SW9621-1 OSPFv2/BFD Verification
SW9621-1#
show bfd neighbors
OurAddr NeighAddr LD/RD RH/RS Holdown(mult) State
Int Vrf
10.10.10.9 10.10.10.10 1090519042/1090519042 Up 9193(5) Up
Eth2/3 default
SW9621-1#
show ip ospf interface
Ethernet2/3 is up, line protocol is up
IP address 10.10.10.9/30
Process ID 21 VRF default, area 0.0.0.5
Enabled by interface configuration
State DR, Network type BROADCAST, cost 40
BFD is enabled
Index 2, Transmit delay 1 sec, Router Priority 1
Designated Router ID: 1.1.1.1, address: 10.10.10.9
Backup Designated Router ID: 1.1.1.15, address: 10.10.10.10
1 Neighbors, flooding to 1, adjacent with 1
Timer intervals: Hello 25, Dead 100, Wait 100, Retransmit 5
Hello timer due in 00:00:04
No authentication
Number of opaque link LSAs: 0, checksum sum 0
Example 1-17 shows SW9621-15 BFD configurations and neighbors.
Example 1-17 Router 4 Config and Verification (SW9621-15)
SW9621-15(config)#
feature bfd
SW9621-15(config)#
interface Ethernet2/1
SW9621-15(config-if)#
ip ospf bfd
SW9621-15(config-if)#
no ip redirects
SW9621-15(config-if)#
no ipv6 redirects
SW9621-15(config-if)#
bfd interval 100 min_rx 100 multiplier 5
SW9621-15#
show bfd neighbors
OurAddr NeighAddr LD/RD RH/RS Holdown(mult)
State Int Vrf
10.10.10.10 10.10.10.9 109051902/109051902 Up 9190(5)
Up Eth2/1 default
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