Survivable Design of Multi-Domain Multi-Layer Backbone Networks

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Reliable communication networks and services are critical to modern societies. Our focus is to assess and improve reliability of backbone networks carrying aggregated user communication traffic within a metropolitan area, or across a region or country, or among continents. Currently, backbone networks are technologically organized in a hierarchy, which consists of multiple layers. At an upper layer, Internet Protocol (IP)-based user traffic is dominant, carried by data packets. Many IP services require certain quality of service, including service reliability, and thus are carried as IP flows, as opposed to individual packets. IP links in the upper layer are implemented in lower layers as reconfigurable circuits, such as lightpaths in Wavelength Division Multiplexing (WDM) networks. Protections to IP flows can be accomplished by providing backup IP paths at the upper layer, or providing backup lightpaths at lower layers, or a combination of both. Although single layer network and service reliability has been extensively studies for two decades, in a multi-layer network environment, a lot of important problems remain unsolved, for example, how to quantify the availability of IP flows when IP-link failures are not independent as a result of complicated mappings of IP links to lower-layer circuits, how to find the locations and then isolate network faults or attacks, how to protect against multiple network failures or attacks, etc. Independent of technological hierarchy, backbone networks also are administered as multiple administration domains or by different network operators. For end users, it is end-to-end service reliability that matters, not the reliability of network links or segments. Therefore, design and coordination of protections across multiple domains are important, however, also very challenging due to limited information sharing across domains and sometime competitive relations among network operators. This proposed project will investigate the design issues of service protection in a multi-domain multi-layer network environment.