MPLS and Next-Generation Networks: Foundations for NGN and Enterprise Virtualization

Customers generally desire the lowest-cost portfolio of WAN services that meet their quality objectives and connectivity requirements. Total cost of ownership factors include staff training, equipment, service charges, and service exit fees, such as those incurred when subscribing to an alternative service. For these customers, WAN connectivity costs are high due to the multiplicity of protocols implemented by the service providers. Because legacy services are expected to be matched by new service offerings, an Ethernet interface for WAN connectivity is attractive for customers because of the potential cost savings that is attributed to the removal of the protocol. Transparent LAN service (TLS) originates from metro-Ethernet at the access. Multicast-aware, VPN-based service is an example of an enhanced service offering that is needed to support IP-TV, videoconferencing, and push applications, such as stock market quotations. Internet access and secure firewall services broaden the service provider's portfolio for enhanced services, all of which can be deployed over IP/MPLS. Layer 2 MPLS services can lower transmission division multiplexing (TDM) switching costs by emulating existing Frame Relay and ATM services. MPLS traffic engineering (TE) and fast reroute (FRR) can replace synchronous digital hierarchy (SDH) for network resilience under failure scenarios. Layer 3 MPLS VPNs offer any-to-any connectivity, with support of data, voice, and video intranet applications via differentiated CoS mechanisms. Chapter 2 discusses these services in more detail.