A Versatile Control Plane for EPON-based FTTX Access Networks
The Ethernet PON (EPON), standardized by the IEEE Ethernet First Mile Alliance, is viewed by many as an attractive solution to deliver very high-speed broadband access. While downstream traffic is broadcasted to all customers, the access of upstream traffic to the fiber has to be arbitrated in order to avoid collisions. This is achieved by designing both a Dynamic Bandwidth Assignment (DBA) that shares bandwidth opportunities between customers, and a scheduling policy, which is used by customers to take advantage of the allocated bandwidth opportunities. The DBA and the settings of the scheduling policy are part of the control plane of the PON, and thus characterize which types of services can be supported by the operator. EPON are widely deployed in some geographical areas, but usually offer a simple Best Effort access network. This paper proposes a versatile control plane for EPONs that can be configured to support either a classless Best Effort network, or several relative Classes of Services, or a mix of committed bandwidth and Best Effort services. This control plane includes a framework for enforcing Service Level Agreements, and fairly sharing available resources. The paper also addresses the issue of Connection. Acceptance Control for EPONs and explains its relationship with the DBA. The proposed framework is easily configured (all the control being centralized at the OLT or in the backbone) while allowing the support of large varieties of services.