Layer 1 Virtual Private Networks

Tomonori Takeda
NTT

This presentation addresses Layer 1 Virtual Private Networks (L1VPNs). It describes motivations, possible deployment scenarios, service models, requirements and applicability of GMPLS (Generalized MPLS) for L1VPNs, along with progress in standardization bodies.

Carriers are deploying optical technologies to construct metro and core networks. Metro and core networks are expected to offer enhanced capabilities, such as support of multiple service networks and value-added services. This presentation highlights L1VPNs that provide L1 service to multiple customers over the single optical network with separate control and management capabilities. Possible deployment scenarios of L1VPNs, such as carrier's carrier and multi service backbone, are described. Comparison with other services, such as L2/L3 VPNs, is also investigated.

In L1VPNs, the service offered to customers may differ depending on customer's need, and this presentation presents and compares various service models, in terms of how customers access the service (e.g., management-based service access vs. control-based service access), and what kind of functionalities are given to customers (e.g., signaling vs. signaling and routing). We see that management-based service access would be suitable for supporting legacy networks, while control-based service access enables advanced features, such as rapid fault notification and seamless operation by control plane protocols.

L1VPNs require great support of intelligent control plane protocols, such as GMPLS, both within the provider network and between the provider network and the customer network. This presentation also addresses requirements and applicability of GMPLS to support L1VPNs.GMPLS provides tools, such as signaling and routing, to automate control and management of optical networks. We envision that the same protocols are reused as much as possible over various service models discussed in this presentation, with delta functionalities added along the progress of service models. Recent standardization status is touched as well.