What is a limitation of LDP?

LDP Summary
The LDP protocol is used to dynamically signal MPLS LSPs. You must configure family mpls
support on your router interfaces, and enable a MPLS instance on the router before you can
dynamically signal LSPs. The configuration and operation of LDP is pretty straightforward. At
a minimum, you must configure an LDP instance and associate one or more MPLS-enabled
interfaces with the LDP instance before LDP signaling can begin. Once configured, LDP will
automatically detect neighbors and establish a TCP-based session to each neighbor for the
purpose of establishing LSPs through the exchange of FECs. Heck, the hardest part about LDP
is preventing the automatic establishment of LSPs to all other LDP-enabled routers! LDP relies
on the IGP for loop detection and forwarding, which means that the LDP does not support
traffic engineering in that the forwarding path of an LDP signaled LSP will always match that
used by the IGP.
By default, JUNOS software will automatically advertise a FEC for /32 interface routes,
which in most cases means that each router will advertise a FEC for its loopback address/
RID only.
Various commands are available to monitor the operation of LDP and to view the resulting
label database. LDP signaled LSPs are placed into the inet.3 routing table by default. Because
entries in inet.3 are used only for BGP next hop resolution, traffic sent to internal addresses,
or the tunnel endpoint itself, will not be forwarded over the signaled LSP.