Reference Guide

* - Active session role
Ad Dn - Admin Down
C - CLI
I - ISIS
O - OSPF
R - Static Route (RTM)
LocalAddr RemoteAddr Interface State Rx-int Tx-int Mult Clients
* 2.2.2.2 2.2.2.1 Gi 2/1 Up 100 100 3 I
Changing IS-IS Session Parameters
BFD sessions are configured with default intervals and a default role.
The parameters that you can configure are: Desired TX Interval, Required Min RX Interval, Detection Multiplier, and
system role. These parameters are configured for all IS-IS sessions or all IS-IS sessions out of an interface. If you
change a parameter globally, the change affects all IS-IS neighbors sessions. If you change a parameter at the interface
level, the change affects all IS-IS sessions on that interface.
To change parameters for all IS-IS sessions or for IS-IS sessions on a single interface, use the following commands.
To view session parameters, use the show bfd neighbors detail command, as shown in Verifying BFD
Sessions with BGP Neighbors Using the show bfd neighbors Command in Displaying BFD for BGP Information.
• Change parameters for all IS-IS sessions.
ROUTER-ISIS mode
bfd all-neighbors interval milliseconds min_rx milliseconds multiplier value
role [active | passive]
• Change parameters for IS-IS sessions on a single interface.
INTERFACE mode
isis bfd all-neighbors interval milliseconds min_rx milliseconds multiplier
value role [active | passive]
Disabling BFD for IS-IS
If you disable BFD globally, all sessions are torn down and sessions on the remote system are placed in a Down state.
If you disable BFD on an interface, sessions on the interface are torn down and sessions on the remote system are
placed in a Down state. Disabling BFD does not trigger a change in BFD clients; a final Admin Down packet is sent
before the session is terminated.
To disable BFD sessions, use the following commands.
• Disable BFD sessions with all IS-IS neighbors.
ROUTER-ISIS mode
no bfd all-neighbors
• Disable BFD sessions with IS-IS neighbors on a single interface.
INTERFACE mose
isis bfd all-neighbors disable
Configure BFD for BGP
Bidirectional forwarding detection (BFD) for BGP is supported on the S4820T platform.
In a BGP core network, BFD provides rapid detection of communication failures in BGP fast-forwarding paths between
internal BGP (iBGP) and external BGP (eBGP) peers for faster network reconvergence. BFD for BGP is supported on
1GE, 10GE, 40GE, port-channel, and VLAN interfaces. BFD for BGP does not support IPv6 and the BGP multihop feature.
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