Cisco's Spatial Reuse Protocol(SRP) is used at the MAC layer of Dynamic Packet Transport( DPT) and in the Resilient Packet Ring( RPR). It defines a fast network protocol for packet transmission in elastic ring topologies.
The Spatial Reuse Protocol is independent of the transport layer and supports a wide variety of physical media such as dark fiber, wavelength division multiplexing(WDM), and SDH paths. In this protocol, a transmission link between two SRP nodes is used multiple times because the nodes remove the data packets from the ring immediately after receiving them. Bottlenecks are eliminated through distributed bandwidth management. The SRP protocol has a significant bandwidth gain over SDH/Sonet due to the spatial (spatial) multiple utilization of a link.