When I using MPLS Auto-tunnel backup feature and running MPLS L3 VPN Services , I am unable to get the Lables over this tunnel for the BGP VPNv4 Peer as this tunnel is not enabled for MPLS by default.
I need to go and manually config this Tunnel Interface for MPLS to achieve that.
I was thinking is there a way to do it dynamically, the way we have it for auto-tunnel primary using this command
mpls traffic-eng auto-tunnel primary config mpls ip.
I am not seeing any such command for auto-tunnel backup.
Right, the rule is that the primary tunnel is never seen down, just encapsulated in the backup tunnel by adding one level of tag(thanks to rsvp), so no need of ldp running through this backup tunnel, as your primary tunnel is still alive,and taking care of your LDP lsp.
In the case of auto tunnel, as the primary tunnel is a one hop tunnel only you don't have any rsvp label stacked, as it is poped because of implicit-null behavior.However, you will notice the label added by rsvp when encapsulating the primary tunnel in the backup tunnel, so you will have the following labels from bottom to top of the stack when primary path broken : vpn label, ldp label(obtained over the rsvp tunnel),rsvp label(backup tunnel)
Also make sure Auto-tunnel is right for you as there are caveats, not very NSF friendly, and no control on your tunnel numbering, as a tunnel could have his name changed on a reboot for example.So not very cool for troubleshooting and monitoring.