A router acting as a stitching point between two LSPs maps the ELC received in signaling for a downstream segment to the upstream segment for the level in the LSP hierarchy being stitched.
If an LSR is stitching an RSVP or LDP segment to a downstream segment of a tunnel type that does not support ELC signaling (for example, BGP) and override-tunnel-elc is configured at the LSR for to downstream segment, then the system signals ELC on the upstream LSP segment. The override-tunnel-elc command must be configured to reflect whether all possible downstream LERs are entropy-label-capable; otherwise, packets with an EL are discarded by a downstream LER that is not entropy-label-capable.
The mapping of ELC across LDP-BGP stitching points is not supported. If a downstream tunnel endpoint signals ELC, this signal is not automatically propagated upstream. The EL and ELI are not inserted on these LSPs by the ingress LER.