Service providers and enterprises are meeting customer demand by building scalable, feature-rich networks that can deliver profitable value-added services such as multiprotocol label switching (MPLS) virtual private networks (VPNs); voice, video, and data integration; and tiered service offerings. These services must be deployed with uncompromised reliability and scalability. To be economically and operationally feasible, this network must reduce the layers of equipment and management versus services offered over multiple parallel networks.

Data, rather than voice circuits, dominates today's bandwidth requirements. New services such as IP VPN, voice over IP (VoIP), and digital video are no longer confined within the corporate local-area network (LAN). These applications are placing new requirements on metropolitan-area network (MAN) and wide-area network (WAN) transport. RPR is uniquely positioned to fulfill these bandwidth and feature requirements as networks transition from circuit-dominated to packet-optimized infrastructures.

Resilience	Proactive span protection automatically avoids failed spans within 50 ms.
Services	Support for latency/jitter sensitive traffic such as voice and video.Support for committed information rate (CIR) services.
Efficiency	Spatial reuse: Unlike SONET/SDH, bandwidth is consumed only between the source and destination nodes. Packets are removed at their destination, leaving this bandwidth available to downstream nodes on the ring.
Scalable	Supports topologies of more than 100 nodes per ring. Automatic topology discovery mechanism.

Table 1. Resilient Packet Ring Technology Key Features

Service providers worldwide, such as cable multiple-system operators (MSOs), Internet service providers (ISPs), exchange-point operators, and Post Telephone and Telegraph Administrations (PTTs), have deployed current RPR solutions from companies such as Cisco Systems, Nortel Networks, and Sun Microsystems. The SRP, defined in IETF RFC 2892, is the most widely deployed solution today, with products from a multitude of companies and more than 200 customers worldwide.

The IEEE is currently defining the standard for a RPR MAC in the 802.17 working group. Completion of the IEEE standard is expected mid-2003.