RPR—Building A Better Ethernet?
by Robert Bellman

Published September 2001

Abstract:

Network service providers need a new kind of optical ring technology to deliver high-speed metro Ethernet services—at least that's what some vendors think. Companies like Appian Communications, Cisco, Dynarc and Lantern Communications are developing resilient packet ring (RPR) technologies, which replace Ethernet's media access control (MAC) layer with a new ring-based MAC. Atrica and a few others are addressing the challenge with ring-based solutions that preserve the Ethernet MAC. All these approaches promise service providers the best of both worlds: Ethernet's low cost and packet data efficiency, plus SONET's ring structure, reliability and rapid restoral.

Sensing a groundswell, the IEEE formed the 802.17 working group late last year to standardize RPR. A marketing consortium, the RPR Alliance, was formed in January. The IETF also has a working group called IP over RPR (IPoRPR).

But 802.17 has a sweeping agenda that could slow progress toward its most basic goals. A recent RPR Alliance press release declares, "RPR will support carrier-class, service-level-agreement-based metro Ethernet, IP, and legacy TDM services." If I were a member of the 802.17 working group, the breadth of that statement would worry me. The working group needs to keep its eye on the ball—efficient, robust metro-area data services—or 802.17 is destined for a one-way trip to the protocol museum.

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