Fault handling mechanisms in the RETHER protocol

RETHER is a software-driven token-passing protocol designed to provide bandwidth guarantee for real-time multimedia applications over off-the-shelf Ethernet hardware. To our knowledge, it is the first all-software and fully-implemented real-time protocol on top of commodity Ethernet hardware. Because token passing is used to regulate network accesses, node crashes and/or packer corruption may lead to token loss, thus potentially shutting down the network completely. This paper describes the fault handling mechanisms built into RETHER to address this problem in both a single-segment and multi-segment Ethernet environment. The emphasis of the paper is on the uniqueness of the target application context and the rationale of chosen solutions. We present the performance tradeoffs of the fault detection/recovery schemes, the implementation experiences of the prototype.