Reliable Multi-Bit-Rate VPN Provisioning for Multipoint Carrier-Grade Ethernet Services Over Mixed-Line-Rate WDM Optical Networks

Ethernet´s success in local-area networks (LANs) is fueling the efforts to extend its reach to cover metro and long-haul networks. A key enabler for using Ethernet in the carrier´s network is its ability to efficiently sup port multipoint-to-multipoint (MP2MP) services. MP2MP service is the core underlying structure to enable standard Ethernet services such as Ethernet virtual private networks (E-VPNs). Since most of the research, standardization, and development have focused on designing protection architectures for point-to-point (P2P) Ethernet connections, protecting E-VPN services is an important research problem. Among the various transport methods for realizing carrier Ethernet, the wavelength-division multiplexing (WDM) optical network is a strong candidate. Wavelength channel rates are increasing from 10 to 40 Gbits/s and even 100 Gbits/s, and they can also coexist in the same fiber. We study the problem of cost-efficient provisioning of multi-bit-rate (1/10/40/100 Gbits/s) self-protected E-VPN demands over a carrier-grade Ethernet network employing WDM optical network (Ethernet over WDM) with mixed line rates (MLRs). We study two algorithms for self-protected E-VPN provisioning. The first algorithm reforms the original E-VPN topology and increases the provisioning rates (10/40/100 Gbits/s) of the E-VPN edge demands to create excess capacity that can be used for protection (E-VPN reformation). The second algorithm routes the E-VPN edge demands using the lowest available rate (10/40/100 Gbits/s) and establishes backup capacity for protecting the E-VPN (no E-VPN reformation). Our algorithms are tested on a 17-node German national network topology. The results show that using E-VPN reformation achieves significant cost reduction and significant improvement in the network´s performance by reducing the traffic-blocking ratio.