Consensus reached on RPR

An IEEE working group has agreed on a single baseline document for the Resilient Packet Ring standard.

The Resilient Packet Ring Alliance, an industry advocacy group promoting the standardisation of resilient packet ring (RPR) technology, has announced that the IEEE 802.17 Working Group agreed on a single baseline draft for the RPR standard at its meeting this week in Orlando.

To date, more than 400 people have participated in the IEEE 802.17 RPR standard development efforts. The January meeting included representatives from systems vendors, silicon suppliers, public network providers as well as university and nonprofit organizations.

The baseline document for the RPR standard resulting from this working group meeting received support from greater than 75% of the participants. The working group will meet again in March to continue developing the standard.

‘RPR is considered one of the leading technologies for carriers to build new and upgrade existing metro data networks,’ said Robert Love, chair of the RPR Alliance and vice chair of the IEEE 802.17 Working Group.

RPR itself is a new media access control (MAC) protocol closely related to Ethernet but designed to optimize bandwidth utilisation and facilitate services over a ring network.

It is designed to provide the carrier-class attributes normally associated with SONET and SDH – including 50-millisecond ring protection, full FCAPS management, and TDM service support – over an infrastructure that is optimised for emerging packets services.

RPR then becomes a multi-service transport protocol based on packets rather than circuits, and RPR systems are seen by many carriers as the inevitable successors to SONET/SDH add-drop multiplexers (ADMs).

According to the Alliance, RPR provides both legacy TDM and differentiated packet-based services (such as native Ethernet) over a single, converged network. For carriers, it promises to deliver all the needed end user services – TDM voice, VPN data, and Internet access – at dramatically lower equipment, facility, and operating costs.

TDM voice is typically delivered over synchronous T1/E1 or DS3/E3 circuits, which can carried over RPR without compromising ‘toll quality.’ VPN and Internetdata services – today delivered using PPP, frame relay, or ATM over TDM circuits (all the way from DS-1 to OC-48) – can also be carried over an RPR-based transport infrastructure in their native form.

Furthermore, over an RPR-based infrastructure, these services can be gradually migrated to be carried more efficiently using native Ethernet private lines or transparent LAN services (TLS) with service quality parameters equivalent to frame relay.