bfd color—Configure the Bidirectional Forwarding Protocol timers used on transport tunnels (on vEdge routers only).
Note: BFD is always enabled on vEdge routers. There is no shutdown configuration command to disable it.
vManage Feature Template
For vEdge routers only:
Configuration ► Templates ► BFD
bfd color color hello-interval milliseconds multiplier number pmtu-discovery
- Hello Packet Interval
- hello-interval milliseconds
For the transport tunnel, how often BFD sends Hello packets. BFD uses these packets to detect the liveness of the tunnel connection and to detect faults on the tunnel.
Range: 100 through 300000 milliseconds (5 minutes)
Default: 1000 milliseconds (1 second)
- Identifier for the Transport Tunnel
- color color
Transport tunnel for data traffic moving between vEdge routers. The color identifies a specific WAN transport provider.
Values: 3g, biz-internet, blue, bronze, custom1, custom2, custom3, default, gold, green, lte, metro-ethernet, mpls, private1 through private6, public-internet, red, silver
- Multiplier for the Hello Packet Interval
- multiplier number
How many Hello packet intervals BFD waits before declaring that a tunnel has failed. BFD declares that the tunnel has failed when, during all these intervals, BFD has received no Hello packets on the tunnel. This interval is a multiplier of the Hello packet interval time. For example, with the default Hello packet interval of 1000 milliseconds (1 second) and the default multiplier of 7, if BFD has not received a Hello packet after 7 seconds, it considers that the tunnel has failed and implements its redundancy plan.
Range: 1 through 60
Default: 7 (for hardware vEdge routers), 20 (for vEdge Cloud software routers)
- Path MTU Discovery
Control BFD path MTU discovery on the transport tunnel. By default, BFD PMTU discovery is enabled, and it is recommended that you do not modify this behavior. With PMTU discovery enabled, the path MTU for the tunnel connection is checked periodically, about once per minute, and it is updated dynamically. With PMTU discovery enabled, 16 bytes might be required by PMTU discovery, so the effective tunnel MTU might be as low as 1452 bytes. From an encapsulation point of view, the default IP MTU for GRE is 1468 bytes, and for IPsec it is 1442 bytes because of the larger overhead. Enabling PMTU discovery adds to the overhead of the BFD packets that are sent between the vEdge routers, but does not add any overhead to normal data traffic.
If PMTU discovery is disabled, the expected tunnel MTU is 1472 bytes (tunnel MTU of 1500 bytes less 4 bytes for the GRE header, 20 bytes for the outer IP header, and 4 bytes for the MPLS header). However, the effective tunnel MTU might be 1468 bytes, because the software might sometimes erroneously add 4 bytes to the header.
Note that the default BFD configuration is not displayed when you issue the show running-config command. This is because BFD is always enabled on vEdge routers, and there is no shutdown configuration command to disable it. However, if you configure additional BFD properties, they are displayed by the show running-config command.
Change the BFD Hello packet interval for the lte tunnel connection to 2 minutes:
vEdge# show running-config bfd bfd color lte hello-interval 2000 !
Command introduced in Viptela Software Release 14.1.
In Release 15.1, added pmtu-discovery option, renamed interval option to hello-interval, and changed Hello interval units from seconds to milliseconds.
In Release 15.1.1, default multiplier changed from 3 to 7.
Colors private3, private4, private5, and private6 added in Release 15.2.
Starting in Release 15.3.2, path MTU discovery is enabled by default.
In Release 16.1, default multiplier added for vEdge Cloud routers.
In Release 16.2, maximum hello interval changed from 60 seconds to 5 minutes.