MPLS - what is seamless MPLS
A large MPLS network may have several different types of services running in various areas of the network. Larger infrastructures are usually divided into core and aggregation areas each with a different design. Often, each component will used different IGPs, and prefixes from one area cannot be redistributed into another area.
In such a scenario, end to end label switched paths (LSPs) cannot be established.
Seamless MPLS introduces separation of the service and transport planes and provides end to end service independent transport. It removes the need for service specific configurations in network transport nodes.