First you need to understand that RPR or Resilient Packet Rings are currently only marketing terminologies, with each vendor offering their own particular implementation. The IEEE is working on the 802.17 specification, which will offer a standards based implementation.
What really needs to be considered is the applications that need to be supported. Point to point services, for example, obviously, do not require RPR. For shared network architectures, the 802.17 efforts are trying to resolve two key issues - efficient bandwidth utilization and network resiliency. The prior can be delivered today by implementing Layer 2/3 grooming at the network edges. This enables statistical multiplexing and over-subscription, thus improving the network utilization. When delivering data services over a SONET/SDH transport network, the resiliency schemes, inherent to these technologies could be leveraged to offer the sub 50 ms resiliency. In data only networks, 802.17 will play a bigger role, at least with respect to resiliency.
