How to config bfd

How to config bfd

BFD (Bidirectional Forwarding Detection): 

Bidirectional Forwarding Detection (BFD) is a lightweight network protocol designed to detect link failures rapidly between two forwarding engines (e.g., routers or switches). BFD operates independently of media, routing protocols, and data plane, enabling sub-second failure detection. In this document, we explore BFD configuration and validation on SONiC switches integrated with BGP. 

 

Tested model & firmware version: 

  • Switch model name: 

Accton-AS5712-54X 

  • Community sonic version: 

202211.2 

 

TOPOLOGY: 

        

 

Configuration commands (sonic configurations) 

Note: Commands are to be executed in sudo and vtysh mode. 

Step1: Configure the IP address and Loopback address as per topology. Refer to ip interface configuration. 

Step2: Configure the EBGP and add the BFD in EBGP neighbor. 

R1: 

root@sonic:/home/admin# vtysh 

sonic.PALCNETWORKS.COM# configure terminal 

sonic.PALCNETWORKS.COM(config)# router bgp 100 

sonic.PALCNETWORKS.COM(config-router)# neighbor 20.1.1.2 remote-as 200 

sonic.PALCNETWORKS.COM(config-router)# neighbor 20.1.1.2 bfd 

sonic.PALCNETWORKS.COM(config-router)# network 1.1.1.1/32 

sonic.PALCNETWORKS.COM(config-router)# network 20.1.1.0/24 

R2: 

root@sonic:/home/admin# vtysh 

sonic.PALCNETWORKS.COM# configure terminal 

sonic.PALCNETWORKS.COM(config)# router bgp 200 

sonic.PALCNETWORKS.COM(config-router)# neighbor 20.1.1.1 remote-as 100 

sonic.PALCNETWORKS.COM(config-router)# neighbor 20.1.1.1 bfd 

sonic.PALCNETWORKS.COM(config-router)# network 2.2.2.2/32 

sonic.PALCNETWORKS.COM(config-router)# network 20.1.1.0/24 

 

Step3: Configure the time interval for BFD in all interfaces. 

R1: 

sonic.PALCNETWORKS.COM(config)# bfd 

sonic.PALCNETWORKS.COM(config-bfd)# peer 20.1.1.2 

sonic.PALCNETWORKS.COM(config-bfd-peer)# detect-multiplier 3 

sonic.PALCNETWORKS.COM(config-bfd-peer)# receive-interval 100 

sonic.PALCNETWORKS.COM(config-bfd-peer)# transmit-interval 100 

R2: 

sonic.PALCNETWORKS.COM(config)# bfd 

sonic.PALCNETWORKS.COM(config-bfd)# peer 20.1.1.1 

sonic.PALCNETWORKS.COM(config-bfd-peer)# detect-multiplier 3 

sonic.PALCNETWORKS.COM(config-bfd-peer)# receive-interval 100 

sonic.PALCNETWORKS.COM(config-bfd-peer)# transmit-interval 100 

 

Step4: Check the BFD Configuration on R1 and R2. 

R1: 

Sonic.PALCNETWORKS.COM# show bfd peer 20.1.1.2 

BFD Peer: 

        peer 20.1.1.2 local-address 20.1.1.1 vrf default interface Ethernet49 

                ID: 1545681435 

                Remote ID: 2494635853 

                Active mode 

                Status: up 

                Uptime: 2 minute(s), 50 second(s) 

                Diagnostics: ok 

                Remote diagnostics: ok 

                Peer Type: configured 

                Local timers: 

                        Detect-multiplier: 3 

                        Receive interval: 200ms 

                        Transmission interval: 200ms 

                        Echo receive interval: 50ms 

                        Echo transmission interval: disabled 

                Remote timers: 

                        Detect-multiplier: 3 

                        Receive interval: 100ms 

                        Transmission interval: 100ms 

                        Echo receive interval: 50ms 

 

sonic.PALCNETWORKS.COM# show ip bgp summary 

  

IPv4 Unicast Summary (VRF default): 

BGP router identifier 1.1.1.1, local AS number 100 vrf-id 0 

BGP table version 17 

RIB entries 13, using 2392 bytes of memory 

Peers 1, using 723 KiB of memory 

  

Neighbor        V         AS   MsgRcvd   MsgSent   TblVer  InQ OutQ  Up/Down State/PfxRcd   PfxSnt Desc 

20.1.1.2        4        200        48        59        0    0    0 00:00:02            3        7 N/A 

R2: 

Sonic.PALCNETWORKS.COM# show bfd peer 20.1.1.1 

BFD Peer: 

        peer 20.1.1.1 local-address 20.1.1.2 vrf default interface Ethernet49 

                ID: 1545681435 

                Remote ID: 2494635853 

                Active mode 

                Status: up 

                Uptime: 1 minute(s), 15 second(s) 

                Diagnostics: ok 

                Remote diagnostics: ok 

                Peer Type: configured 

                Local timers: 

                        Detect-multiplier: 3 

                        Receive interval: 200ms 

                        Transmission interval: 200ms 

                        Echo receive interval: 50ms 

                        Echo transmission interval: disabled 

                Remote timers: 

                        Detect-multiplier: 3 

                        Receive interval: 100ms 

                        Transmission interval: 100ms 

                        Echo receive interval: 50ms 

 

sonic.PALCNETWORKS.COM# show ip bgp summary 

  

IPv4 Unicast Summary (VRF default): 

BGP router identifier 2.2.2.2, local AS number 200 vrf-id 0 

BGP table version 113 

RIB entries 17, using 3128 bytes of memory 

Peers 1, using 723 KiB of memory 

  

Neighbor        V         AS   MsgRcvd   MsgSent   TblVer  InQ OutQ  Up/Down State/PfxRcd   PfxSnt Desc 

20.1.1.1        4        100       214       179        0    0    0 00:02:43            7        9 N/A 

 

Step5: Shutdown the Ethernet49 port from R1 and check the bfd status: 

R1: 

sonic.PALCNETWORKS.COM# show bfd peer 20.1.1.2 

BFD Peer: 

        peer 20.1.1.2 local-address 20.1.1.1 vrf default interface Ethernet49 

                ID: 1545681435 

                Remote ID: 2494635853 

                Active mode 

                Status: down 

                Uptime: 10 second(s) 

                Diagnostics: ok 

                Remote diagnostics: ok 

                Peer Type: configured 

                Local timers: 

                        Detect-multiplier: 3 

                        Receive interval: 200ms 

                        Transmission interval: 200ms 

                        Echo receive interval: 50ms 

                        Echo transmission interval: disabled 

                Remote timers: 

                        Detect-multiplier: 3 

                        Receive interval: 100ms 

                        Transmission interval: 100ms 

                        Echo receive interval: 50ms 

 

sonic.PALCNETWORKS.COM# show ip bgp summary 

  

IPv4 Unicast Summary (VRF default): 

BGP router identifier 1.1.1.1, local AS number 100 vrf-id 0 

BGP table version 15 

RIB entries 9, using 1656 bytes of memory 

Peers 1, using 723 KiB of memory 

  

Neighbor        V         AS   MsgRcvd   MsgSent   TblVer  InQ OutQ  Up/Down State/PfxRcd   PfxSnt Desc 

20.1.1.2        4        200        40        46        0    0    0 00:00:15       Active        0 N/A 

  

Total number of neighbors 1 

 

R2: 

Sonic.PALCNETWORKS.COM# show bfd peer 20.1.1.1 

BFD Peer: 

        peer 20.1.1.1 local-address 20.1.1.2 vrf default interface Ethernet49 

                ID: 1545681435 

                Remote ID: 2494635853 

                Active mode 

                Status: down 

                Uptime: 20 second(s) 

                Diagnostics: ok 

                Remote diagnostics: ok 

                Peer Type: configured 

                Local timers: 

                        Detect-multiplier: 3 

                        Receive interval: 200ms 

                        Transmission interval: 200ms 

                        Echo receive interval: 50ms 

                        Echo transmission interval: disabled 

                Remote timers: 

                        Detect-multiplier: 3 

                        Receive interval: 100ms 

                        Transmission interval: 100ms 

                        Echo receive interval: 50ms 

 

sonic.PALCNETWORKS.COM# show ip bgp summary 

  

IPv4 Unicast Summary (VRF default): 

BGP router identifier 2.2.2.2, local AS number 200 vrf-id 0 

BGP table version 32 

RIB entries 3, using 552 bytes of memory 

Peers 1, using 723 KiB of memory 

  

Neighbor        V         AS   MsgRcvd   MsgSent   TblVer  InQ OutQ  Up/Down State/PfxRcd   PfxSnt Desc 

20.1.1.1        4        100        56        48        0    0    0 00:01:20       Active        0 N/A 

  

Total number of neighbors 1 

 

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