Highly Available and Reliable Networks based on Commercial-off-the-shelf Hard- and Software

The steady replacement of circuit-switched networks by packet-switched networks pave the way for Voice over Internet Protocol (VoIP) into domains that long have been the market for proprietary and thus, closed communication systems e. g. for safety-critical purposes. Because the quality of a call is influenced by delay and jitter, fault detection and failover play an important role. Hence, the paper deals with these aspects and perspectives to build highly available and reliable networks based on Commercial-off-the-shelf (COTS) hard- and software. To fulfill the requirement of a sub-second network convergence time, a redundant end system and an access network are studied. The presented tests and results of Layer-2 and Layer-3 protocols show that in most albeit not all cases fault detection and failover times in the range of a few milliseconds are possible.