Network layer based redundancy for time-critical VoIP applications
ABSTRACT Voice over Internet protocol (VoIP) applications are making their way into safety-critical environments. If voice data has to be transmitted in such environments, the connection must not fail and the network has to recover quickly. Additionally, the use of specialized systems that are tailored to a certain application is not a preferred solution. Instead, the use of commercial-off-the-shelf (COTS) hard- and software is required. This paper discusses the use of standardized hard- and software as well as network protocols to allow failover times within the range of milliseconds. A redundant end-system and its network coupling are presented. The Layer 3 protocol OSPF and the combination of OSPF with the protocol-independent Hello protocol BFD are investigated to fulfill the requirements. The tests and the achieved results show a significant reduction of the convergence time.
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ABSTRACT: We describe and analyse in details the various factors that influence the convergence time of intradomain link state routing protocols. This convergence time reflects the time required by a network to react to the failure of a link or a router. To characterise the convergence process, we first use detailed measurements to determine the time required to perform the various operations of a link state protocol on currently deployed routers. We then build a simulation model based on those measurements and use it to study the convergence time in large networks. Our measurements and simulations indicate that sub-second link-state IGP convergence can be easily met on an ISP network without any compromise on stability.Computer Communication Review. 01/2005; 35:35-44.
Conference Proceeding: Achieving sub-50 milliseconds recovery upon BGP peering link failures.Proceedings of the 2005 ACM Conference on Emerging Network Experiment and Technology, CoNEXT 2005, Toulouse, France, October 24-27, 2005; 01/2005
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ABSTRACT: The majority of the proposed methods that ameliorate the QoS in environments with high packet loss rates employing transmission of redundant information use a specific RTP profile. An alternative approach that does not require the usage of such a profile is described and evaluated.Electronics Letters 04/2004; · 1.04 Impact Factor