Seamless Multiprotocol Label Switching (MPLS) is a bearer technology that extends MPLS to access networks. Seamless MPLS establishes an end-to-end label switched path (E2E LSP) across the access, aggregation, and core layers. All services can be encapsulated using MPLS at the access layer and transmitted along the E2E LSP across the three layers.
Seamless MPLS was developed out of a need for greater flexibility in scenarios where traditional MPLS overcomplicates network management. Traditional MPLS can converge multiple networks on an Ethernet-based infrastructure, which fully exerts the advantages of a single-forwarding model and reduces network construction costs. MPLS has been widely used on aggregation and core networks.
Many service providers use MPLS-based L3VPN/L2VPN solutions to construct a multi-service bearer network. A multi-service bearer network is deployed in a three layer hierarchy consisting of an access layer, aggregation layer, and core layer. Service packets that have been encapsulated and transmitted over a VPN tunnel can be sent only within one layer. To transmit service packets from one layer to another, the VPN service needs to be terminated. The device then needs to obtain the original packets and add VLAN or QinQ tags to the packets before sending the packets to another layer, where the packets are encapsulated and transmitted over VPN within the destination layer. This hierarchical deployment requires greater cooperation between different layers, makes network and service expansion more difficult, and increases operation costs for service providers.
Using the Internet Protocol (IP) to forward packets at the access layer, will result in low forwarding efficiency. Because complicated VLAN configurations are required to associate with devices at the aggregation and core layers, using IP to forward packets at the access layer results in poor service scalability. To solve the preceding issue, seamless MPLS was developed to extend MPLS to the access layer when used with MPLS-capable devices with higher performance.
Seamless MPLS is not an entirely new technology. It uses mature BGP, IGP, and MPLS technologies to establish an E2E LSP across the access, aggregation, and core layers, implementing MPLS-based service forwarding on the entire network.
Helps ease communication between the access, aggregation, and core layers on an MPLS network.
Simplifies network provisioning, operations, and maintenance because the technology encapsulates all services and transmits these services along an E2E LSP.
Has high deployment flexibility and scalability. On a seamless MPLS network, an LSP between any two nodes can be established to roll out services.