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MPLS in Access Networks and Seamless MPLS
16.1 INTRODUCTION
To date, MPLS has typically been used in the core part of service provider networks. However, there is now strong interest in using MPLS in the access part of the network. In this chapter, we describe the drivers behind this interest and discuss two models for employing MPLS for this purpose.
16.2 THE BUSINESS DRIVERS
The driving force for the use of MPLS in the access network is network consolidation. Having one type of access technology allows more efficient use of fiber resources and reduces the quantity and different types of network devices required. Network consolidation has been occurring in the core part of service provider networks, with services from multiple separate networks being consolidated onto one common platform based on MPLS. Consolidation is now also occurring in the access part of the network, in order to avoid the CAPEX and OPEX associated with operating several access networks in parallel. Consolidation can also mean that fewer physical sites are required to house equipment, with traffic being carried to more centralized locations. Ethernet is an important ingredient of the new access network, replacing the various legacy Layer 2 and TDM access technologies that have been used in the past. It was realized that while Ethernet provides a convenient link technology for access networks, Layer 2 Ethernet switching is inherently unsuitable as an aggregation scheme for a carrier-class access network. ...
