It depends what you are advertising into LDP. If your ping is to a destination address that is advertised by LDP and there is an end-to-end LSP for that destination, then the ping will be encapsulated and MPLS switched, even if the destination is in the global table. This is how the outer (tunnel) LSP works in MPLS VPN
By default Cisco networks advertise all global networks into LDP. Therefore by default all global traffic is MPLS switched. It is best practice to filter the LDP announcements to only cover the loopback addresses of the PE routers as there is usually no need to use MPLS for any other internal networks. The command mpls ldp advertise-labels for ACL to ACL is used to control advertisement of labels for specific prefixes to LDP peers.
If you want to check whether a destination will be MPLS forwarded, try “show ip cef destination-ip detail”, if you see a label value after the next-hop then you know the IP packet will be MPLS encapsulated and label switched at least to the next-hop. You can also check the MPLS forwarding table (show mpls forwarding-table) and that will show the inbound and outbound labels as well as the prefix.
You may also get a situation where traffic is MPLS encapsulated in only one direction, so the traffic follows an LSP to the destination, but is not encapsulated on the way back. If you are only advertising loopbacks via LDP and you send a ping to a loopback destination address, but source the ping from an IP that is not advertised by LDP then the ping will follow an LSP to the destination, but the return traffic will be normally IP switched (no MPLS) back to the source.
Another thing to consider is penultimate hop popping. If the destination is only a single hop away, the other LSR will advertise a null label. In this case, instead of labelling the traffic the router will forward the raw IP packet to reduce the number of lookups required on the destination router. In this scenario your traffic is unlabelled, although technically it is following an LSP.
ECMP with MPLS works in a similar way to normal CEF load balancing. If there are two different equal cost next-hops for a destination, the MPLS traffic will also be load balanced between the two destinations, using separate LSPs. If you look at the output from “show ip cef destination-ip internal” it may show you the load balancing