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Technical Report Details

Date 3-8-2009
Number DISI-TR-09-03
Title On the RSTP Protocol Acceleration
Authors Vittoria Gianuzzi, Alessandro Di Marco, Paolo Ardoino, Luigi Rocca
Bibtex Entry
E-mail gianuzzi@disi.unige.it
Link http://www.disi.unige.it/person/GianuzziV/DISI-TR-09-03.pdf
Abstract The proposed RSTP protocol modifications are focused to detect and recover link failures over a ring topology within a 50 ms time frame. The solution is not cheap but appears to work, as demonstrated by several experiments conducted on a five node testbed; in particular, during our experiments: 1. the ring was always loop-free 2. failure recovery always occurred within the expected time frame 3. no unexpected topology changes had been detected In order to bring the fail-over latency down to the sub-seconds time frame, the proposal essentially consist in accelerating the RSTP heartbeat of a factor 1000. In other words, the activation timeout of the RSTP state machine as a whole (several state machines do exist, all of them are accelerated) has been lowered from one second to one millisecond. Clearly this affects the protocol overhead, which now attains to the whole processor performance, as stated in the proposalís report and our experiments confirm.
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