These networks are quite common and indeed most data traffic
currently traverses these networks. One of the objectives in creation of the RPR protocol
was to provide these characteristics in a pure packet transport network.
Over-provisioning Alternative
There are other cases where the RPR provides no benefit or may be inappropriate or
impossible to implement. A primary one is when the physical topology of the fiber does
not allow for the creation of a ring. RPR must operate in a ring configuration. If the fiber
topology is a mesh or tree configuration than creation of an RPR will be impossible.
Another case where IEEE 802.17 is not required is one where the point-to-point link
between switches or routers has approximately twice the peak required bandwidth as
required by the applications or customers. In this case the QoS is provided by over provisioning
the link obviating the need for the rigorous QoS provided by RPR. Likewise,
if there are two fiber access routes (dual homing) to buildings that require communication
services, the restoration properties of RPR are redundant.
Typical Deployment Scenarios
RPR is deployed by service providers or by large organizations such as Fortune 500
companies, government, and educational institutions.
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