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Senior Editor

A look at Resilient Packet Ring

May 31, 20042 mins

* RPR promises to bring SONET-like capabilities to metro Ethernet networks

“SONET performance at Ethernet economics!”

That’s usually the chant put forth by proponents Resilient Packet Ring (RPR) – our topic for this week’s Technology Update.

In a nutshell, RPR promises to bring SONET-like capabilities such as fast recovery times from failures, low latency and reduced jitter – to metro Ethernet networks. Metro Ethernet has so far been missing the ability to provide business-class reliability and to manage latency and jitter quality-of-service metrics for voice traffic.

Enter IEEE 802.17, or RPR, to blend the characteristics of the two technologies.

According to our author ( RPR uses Ethernet switching and a dual counter-rotating ring topology to provide SONET-like network resiliency and optimized bandwidth usage, while delivering multi-point Ethernet/IP services.

RPR maintains its own protection scheme and uses physical-layer alarm information as well as Layer 2 protocol communications to detect node and/or link failures. When a failure is detected, the RPR switching mechanism restores networks in less than 50 milliseconds.

Because RPR is a Layer 2 MAC-based technology, it can operate over multiple physical layers, including SONET. The idea is the customers could see the cost benefits of RPR by having it ride over an existing  SONET network to deliver the resilient, efficient, scalable data applications such as VoIP, packet video, business continuance and distance learning.

For more on RPR read:


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