conditions:
- OSPF / ISIS as the IGP
- advertise loopback (/ 32) in IGP for all routers participating in Mesh membership, Each router should see the loopback of the other routers (Identify a block of addresses that you will reserve for mesh tunnel interfaces)
configuration example for all routers participating in Mesh membership:
mpls traffic-eng auto-tunnel mesh
router ospf 1
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
mpls traffic-eng mesh-group 10 Loopback0 area 0
interface Auto-Template100
ip unnumbered Loopback0
tunnel mode mpls traffic-eng
tunnel destination mesh-group 10
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng path-option 1 dynamic
Definition of AutoTunnel Mesh Groups You can see here:
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/mp_te_path_setup/configuration/15-mt/mp-te-path-setup-15-mt-book/mp-te-autotun-mesh.html