vpn 0 interface tunnel-interface last-resort-circuit—Use the tunnel interface as the circuit of last resort (on vEdge routers). By default, this feature is disabled, and the tunnel interface is not considered to be the circuit of last resort.
There is a delay of 7 seconds before switching back to the primary tunnel interface from a circuit of last resort. This delay is to ensure that the primary interface is once again fully operational and is not still flapping.
When you configure a tunnel interface to be a last-resort circuit, the cellular modem becomes dormant and no traffic is sent over the circuit. However, the cellular modem is kept in online mode so that the modem radio can be monitored at all times and to allow for faster switchover in the case the tunnel interface needs to be used as the last resort.
To minimize the amount of extraneous data plane traffic on a cellular interface that is a circuit of last resort, increase the BFD Hello packet interval and disable PMTU discover.
vManage Feature Template
For vEdge routers only:
Configuration ► Templates ► VPN Interface Ethernet
Configure the cellular0 interface to be the circuit of last resort for the vEdge router:
vEdge# show running-config vpn 0 interface cellular0 vpn 0 interface cellular0 ip dhcp-client tunnel-interface encapsulation ipsec color lte last-resort-circuit no allow-service bgp allow-service dhcp allow-service dns allow-service icmp no allow-service sshd no allow-service netconf no allow-service ntp no allow-service ospf no allow-service stun ! clear-dont-fragment mtu 1428 profile 1 no shutdown ! ! vEdge# show running-config bfd bfd color lte hello-interval 300000 no pmtu-discovery !
Command introduced in Viptela Software Release 16.2.