Bidirectional Forwarding Detection (BFD)


When applying [Bidirectional Forwarding Detection (BFD)](/bidirectional-forwarding-detection-bfd) the configuration consists of parameters configured on the interface, as well as under the [routing](/routing) protocol.

The BFD configuration on the interfaces is not linked with any particular [routing protocol](/routing-dynamic-routing-protocols). By issuing the `bfd` command on the interface, you are simply starting the BFD process, and you are setting the parameters (`interval`, `min_rx`, `multiplier` etc) with which BFD will communicate with the BFD entity on the other end of the link.

Once the BFD process is up and running, there are no entries created in the adjacency database yet, and no BFD control packets are sent or received yet. The adjacency creation takes place only when you configure BFD support for a particular routing protocol. That’s the `bfd all-interfaces` command in the [OSPF](/ospf) router mode configuration or the `neighbor fall-over bfd` command for [BGP](/bgp).

If you’re running multiple routing protocols on a router, you can enable BFD for multiple routing protocols, and they’ll use the same BFD configuration parameters as they are set out in on the interface configuration.

The BFD interface configuration is a generic configuration (regardless of the routing protocol) that simply enables the BFD process and sets the communication parameters that will be used with the BFD entity on the other end. The routing protocol configuration for BFD enables the operation of BFD for the specific routing protocol, and it will use the parameters set on the interfaces in question to perform the BFD mechanisms.

Links:

https://forum.networklessons.com/t/bidirectional-forwarding-detection-bfd/1280/89?u=lagapides

https://networklessons.com/cisco/ccie-routing-switching/bidirectional-forwarding-detection-bfd/

BFD - with multiple routing protocols

ASA - Using FQDN in an ACL for VPN split tunnelling

ASA - VTI VPN and MSS

ASA - crypto hardware processing

ASA - emulating an ASA device

ASA - multiple AnyConnect packages

ASA - multiple VPNs between the same endpoints

ASA - number of crypto maps per interface

ASA - object group protocol vs service

ASA - same-security-traffic command

ASA - split-tunnel-policy command

ASA - using FQDN in an ACL

ASA CTM ipsec poll ctl DU_IOCTL_RESUME_POLL ioctl failed error

ASA Contexts operate as separate virtual devices

ASA DDoS protection

ASA DMZ

ASA ECMP static routing

ASA Manual NAT and Auto NAT

ASA NAT control

ASA NAT port forwarding multiple ports to same IP

ASA NAT with DHCP assigned IP address on the  outside interface

ASA NAT with multiple inside subnets

ASA Site-to-Site IKEv1 IPSec VPN recv errors

ASA Static one to one NAT on a range of addresses

ASA Troubleshoot HTTP and ASDM access

ASA VPN with overlapping IP address spaces

ASA active-standby failover preemption

ASA and Firepower reimaging

ASA crypto map and tunnel group preshared keys

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ASA implicit rule

ASA limit CLI and ASDM access to specific users

ASA packet processing algorithm

ASA prerequisites for high availability

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ASA redundant interface

ASA security levels

ASA syslog logging in multiple context mode

ASA to Firepower migration

ASA troubleshooting IPSec

ASA tunnel-group

ASA understanding version numbers

ASA what triggers an active-standby failover

ASA won't respond to pings from different subnet

Anycast

Automation - Ansible connection plugins

BFD - Control Plane Independent (CPI) bit

BFD - intervals and timers

BFD - slow-timers

BFD echo mode and operation details

BFD how an administrative change differs from a failure

BFD one-arm echo

BGP - 4-byte ASN Backward Compatibility

BGP - AFI and SAFI

BGP - AS_Path filtering use cases

BGP - AS_SET and AS_CONFED_SET are deprecated

BGP - Accumulated IGP metric

BGP - Atomic Aggregate Attribute

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BGP - Autonomous System Number

BGP - BGP Algorithm within confederations

BGP - Discontiguous Autonomous Systems

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BGP - End-of-RIB marker

BGP - Equal Cost Multipath AS_Path Attribute

BGP - FSM - Active state

BGP - Finite State Machine (FSM)

BGP - Flowspec

BGP - Graceful Restart Mechanism

BGP - Handling Multiple Communities on a Single Route

BGP - IGP-BGP redistribution best practices

BGP - Labeled Unicast

BGP - Large BGP communities

BGP - Leaking more specific routes

BGP - Loop Prevention

BGP - MED vs AS Prepending

BGP - Multipath Attribute Prerequisites

BGP - Network Layer Reachability Information (NLRI)

BGP - Next Hop Address Tracking vs Route Dampening

BGP - Outbound Route Filtering

BGP - RRs vs confederations

BGP - Synchronization Rule

BGP - TCP Peering Session Process

BGP - The BGP Table

BGP - The BGP table vs the Routing table

BGP - Why is MED non-transitive

BGP - aggregate-address command in action

BGP - aggregate-address default route

BGP - aggregate-address with a single subnet

BGP - auto-summary best practices

BGP - auto-summary feature

BGP - definition of External BGP (eBGP)

BGP - definition of Internal BGP (iBGP)

BGP - eBGP loop prevention mechanism same AS number

BGP - eBGP next hop optimization

BGP - eBGP peerings

BGP - eBGP third party next hop

BGP - iBGP full-mesh peering

BGP - iBGP split horizon rule

BFD - with multiple routing protocols

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