This means the network is composed of two completely separate rings of fiber that are both able to transmit data concurrently.
This design provides for redundancy in case of a fiber cut or link failure, and increased throughput in common situations.
Cisco claims that DPT can run with double the bit-rate of POS due to this characteristic.
As with most other lower layer protocols, there are methods for communicating not only application data between the nodes of a DPT network.
This ensures that a fiber cut or link failure (layer 1 error) will be rectified and IP traffic will be resumed within 50 ms. DPT also contains a "plug and play" feature which dynamically fetches the MAC addresses of neighboring devices which provides for very simple configuration with little to no setup prior to functional data transfer.