of failure. Each system host recursively enumerates the RapidIO fabric, seizing ownership of devices, allocating device IDs to endpoints and updating switch routing tables. When a conflict for ownership occurs, the system host with the larger deviceID wins. The "losing" host releases ownership of its devices and retreats, waiting for the "winning" host. The winning host completes enumeration, including seizing ownership of the losing host. Once enumeration is complete, the winning host releases ownership of the losing host. The losing host then discovers the system by reading the switch routing tables and registers on each endpoint to learn the system configuration. If the winning host does not complete enumeration in a known time period, the losing host determines that the winning host has failed and completes enumeration. System enumeration is supported in Linux by the RapidIO subsystem. Error management RapidIO supports high availability, fault tolerant system design, including hot swap. The error conditions that require detection, and standard registers to communicate status and error information, are defined. A configurable isolation mechanism is also defined so that when it is not possible to exchange packets on a link, packets can be discarded to avoid congestion and enable diagnosis and recovery activities. In-band (port-write packet) and out-of-band (interrupt) notification mechanisms are defined. Form factors The RapidIO specification does not discuss the subjects of form factors and connectors, leaving this to specific application-focussed communities. RapidIO is supported by the following form factors: Advanced Telecommunications Computing Architecture Advanced Mezzanine Card XMC OpenVPX VXS Software Processor-agnostic RapidIO support is found in the Linux kernel. Applications The RapidIO interconnect is used extensively in the following applications: Wireless base stations Aerospace and Military single-board computers, as well as radar, acoustic and image processing systems Video Storage Supercomputing Medical imaging Industrial control and data path applications RapidIO is expanding into supercomputing, server, and storage applications. Competing protocols PCI Express is targeted at the host to peripheral market, as opposed to embedded systems. Unlike RapidIO, PCIe is not optimized for peer-to-peer multi processor networks. PCIe is ideal for host to peripheral communication. PCIe does not scale as well in large multiprocessor peer-to-peer systems, as the basic PCIe assumption of a "root complex" creates fault tolerance and system management issues. Another alternative interconnect technology is Ethernet. Ethernet is a robust approach to linking computers over large geographic areas, where network topology may change unexpectedly, the protocols used are in flux,