Reference Guide

Bidirectional Forwarding Detection (BFD) | 151
Changing session parameters
BFD sessions are configured with default intervals and a default role. The parameters that can be
configured are: Desired TX Interval, Required Min RX Interval, Detection Multiplier, and system role.
These parameters are configured per interface; if a configuration change is made, the change affects all
sessions on that interface.
To change session parameters on an interface:
View session parameters using the command
show bfd neighbors detail, as shown in Figure 7-8.
Disabling BFD for VLANs
If BFD is disabled on an interface, sessions on the interface are torn down. A final Admin Down control
packet is sent to all neighbors, and sessions on the remote system change to the Down state (Message 3).
To disable BFD on a VLAN interface:
Configuring BFD for Port-Channels
Configuring BFD for Port-Channels is supported only on platforms c e
BFD on port-channels is analogous to BFD on physical ports. If no routing protocol is enabled, and a
remote system fails, the local system does not remove the connected route until the first failed attempt to
send a packet. If BFD is enabled, the local system removes the route when it stops receiving periodic
control packets from the remote system.
There is one BFD Agent for VLANs and port-channels, which resides on RP2 as opposed to the other
agents which are on the line card. Therefore, the 100 total possible sessions that this agent can maintain is
shared for VLANs and port-channels.
Caution: When configuring BFD on VLAN or LAG interfaces on the C-Series, Dell Force10 recommends
a minimum value of 500 milliseconds for both the transmit and minimum receive time, which yields a final
detection time of (500ms *3) 1500 milliseconds.
Step Task Command Syntax Command Mode
1 Change session parameters for all
sessions on an interface.
bfd interval milliseconds min_rx
milliseconds multiplier value role [active |
passive]
INTERFACE VLAN
Step Task Command Syntax Command Mode
1 Disable all sessions on a VLAN
interface.
no bfd enable INTERFACE VLAN