LDP Configuration Commands
7210 SAS M, T, X, R6, Mxp MPLS Configuration Guide Page 289
prefer-tunnel-in-tunnel
Syntax [no] prefer-tunnel-in-tunnel
Context config>router>ldp
Description This command specifies to use tunnel-in-tunnel over a simple LDP tunnel. Specifically, the user 
packets for LDP FECs learned over this targeted LDP session can be sent inside an RSVP LSP which 
terminates on the same egress router as the destination of the targeted LDP session. The user can 
specify an explicit list of RSVP LSP tunnels under the Targeted LDP session or LDP will perform a 
lookup in the Tunnel Table Manager (TTM) for the best RSVP LSP. In the former case, only the 
specified LSPs will be considered to tunnel LDP user packets. In the latter case, all LSPs available to 
the TTM and which terminate on the same egress router as this target ed LDP session will be 
considered. In both cases, the metric specified under the LSP configuration is used to control this 
selection.
Note that the lookup in the TTM will prefer a LDP tunnel over an LDP-over-RSVP tunnel if both are 
available. Also note that the tunneling operates on the dataplane only. Control packets of this targeted 
LDP session are sent over the IGP path.