Ethernet virtual private networks (VPNs) complete the service provider service mix — ensuring that they can confidently mix and match Layer 2 and Layer 3 VPN services based on what their customers want. VPLS expands the next-generation VPN service market and enables service providers to offer their customers a Layer 2 multipoint service that provides higher bandwidth than frame relay, with the same QoS as frame relay or ATM. Also, unlike IP- VPNs, which require the enterprise to share routing information, VPLS allows the enterprise to retain routing control and provides the flexibility to support multiple protocols, in addition to IP, that are present in many enterprise networks.
With a next-generation VPLS imple- mentation, service providers can tailor service definitions that directly align with the customers’ business objectives and thereby create value. The Alcatel- Lucent 7450 ESS delivers VPLS today with the ability to have different applications run within a single VPLS service with distinct service level agree- ments (SLAs), as well as an aggregate SLA for each customer. This greater degree of control for service level differentiation is delivered through
an extensive QoS implementation, including hierarchical QoS (H-QoS) as illustrated in Figure 2.
