Mechanisms for OAM on MPLS in large IP backbone networks

Abstract

The telecom industry has an ongoing work on the Operation and Maintenance (OAM) mechanisms for the MultiProtocol Label Switching (MPLS) technology. We are expecting that this technology will be the future platform for sending Internet Protocol (IP) packets through the backbone networks. OAM functionalities that exist or are proposed for MPLS are: Reachability and failure detection, avoidance of congested routers, Simple Network Management Protocol (SNMP) features, fast rerouting functions, traffic engineering and ad-hoc mechanisms like Ping. Our work shows that through a comparison of OAM mechanisms of MPLS to IP, MPLS is superior on the failure detection, fast rerouting and the traffic engineering functionalities. A mechanism shows how one can use our new algorithm (a patent application is planned) to detect specific traffic behavior, making the MPLS backbone handle this traffic more logic. Different OAM mechanisms for MPLS give different levels of redundancy, which is often proportional to the OAM traffic load. We have found that the Connectivity Verification (CV) traffic load should be differentiated between the Label Switched Paths (LSPs) that need protection switching and those that do not. A short period between LSP CV packets is needed whilst still providing the best available bandwidth for working traffic A table shows different proposed fast rerouting and protection switching mechanisms, easing the operator’s choice of that mechanisms to use in large MPLS backbone networks. We propose the ITU-T LSP connectivity verification mechanism, fast rerouting and protection switching, and the use of MPLS MIB as recommended OAM mechanisms for large backbone networks.