After more than three years of development, the resilient package ring (RPR) standard has been ratified, according to the RPR Alliance.
The IEEE 802.17 standard is an alternative Layer 2 technology that is optimized to address the multiservice transport requirements over metro ring topologies. RPR functionality is built into routers, switches and add/drop multiplexers (ADMs).
RPR provides bandwidth multiplication via spatial reuse of ring bandwidth to allow multiple messages on the ring simultaneously; sub-50ms restoration in case of ring or node failure; efficient use of fiber bandwidth through statistical multiplexing within a single optical channel; and elimination of static bandwidth partitioning between services as well as LAN-like “push-button” provisioning of the network based on packet-switched networks.
Future upgrades to the standard include different physical layers and elegant ways of bridging between rings, says John Hawkins, chairman of the RPR Alliance.
Hawkins, who also is the marketing manager for optical networks at Nortel Networks, says vendors likely will be coming to market with their standards-based products in the next few months. Many have been working on them for some time as the draft standard has changed little in the past year.
Zhone Technologies Inc., for example, announced in mid-June RPR technology has been added across its MALC packet loop carrier platforms. And, ADM manufacturer Corrigent Systems demonstrated RPR protection switching over a 10gbps ring using its CM-100 Packet ADM as part of the Metro Ethernet Forum (MEF) live multivendor interoperability showcase at SUPERCOMM.
Hawkins says carriers that have been sitting on the sidelines will now be entering trials with RPR-compliant products and including the spec in their RFPs.
Analyst Michael Howard of Infonetics Research says a recent study found service providers are planning RPR as part of their next-generation networks. “The recently approved IEEE 802.17 RPR standard brings efficiencies to the transport network that can fundamentally change the cost structure of data and TDM services delivery,” Howard says.
“By using RPR, carriers can mix voice, video, and data applications on one converged packet-optimized network with the carrierclass resiliency of the dual-ring architecture.”
While a compliance test suite is forthcoming, Hawkins says the RPR Alliance is unlikely to sponsor interoperability testing between vendors. “At this point rings are not multivendor, so interoperability is not key,” says Hawkins, noting also that the standard environment is a single ring in the metro. However, in the future it is possible interoperability would enable service providers to extend functionality from one ring to another. He says service providers are beginning to use MPLS for this task, but it’s possible that RPR from end to end could be cheaper.
