Feature Description (Seamless MPLS)

1.1.1 Definition

Seamless Multiprotocol Label Switching (MPLS) is a bearer technique that extends MPLS to the access layer so that all services can be encapsulated using MPLS at this layer. Seamless MPLS establishes an end-to-end (E2E) label switched path (LSP) across the access, aggregation, and core layers for service transmission.

1.1.2 Benefits

MPLS integrates multiple networks into an Ethernet so that the advantages of the Ethernets uniform forwarding mode are maximized and network deployment costs are reduced. Nowadays, MPLS has been widely used at aggregation and core layers.

With the network development trend moving towards a flat network structure, metropolitan area networks (MANs) are steadily evolving into the Ethernet architecture, which calls for the application of MPLS on the MANs and access networks. Seamless MPLS was therefore developed to meet this requirement.

Seamless MPLS uses existing Border Gateway Protocol (BGP), Interior Gateway Protocol (IGP), and MPLS techniques to establish an E2E LSP across the access, aggregation, and core layers so that traffic can be encapsulated and forwarded in E2E mode using MPLS.

Seamless MPLS offers the following benefits:

l   Integrates the access, aggregation, and core layers into one MPLS network, encapsulates all services using MPLS, and transmits these services along an E2E LSP. Seamless MPLS simplifies network provisioning, operation, and maintenance.

l   Provides high deployment flexibility and scalability. On a seamless MPLS network, an LSP can be established between any two nodes to roll out services or add nodes.

1.1.3 Application Scenario

As seamless MPLS achieves E2E service transmission along a cross-layer LSP, service traffic can be transmitted between any two points on the LSP. The seamless MPLS network architecture maximizes service scalability using the following functions:

l   Allows access nodes to signal all services to an LSP.

l   Uses the same transport layer convergence technique to rectify all network-side faults, without affecting service transmission.

Seamless MPLS networking solutions are as follows:

l   Intra-AS seamless MPLS: The access, aggregation, and core layers are deployed within a single AS. This solution mainly applies to mobile bearer networks.

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