Network transmissions in high performance networking scenarios, e.g., used for e-science or Grid applications, require quality-of-service guarantees concerning bandwidth availability, but also timing constraints, e.g., deadlines, must be met. Current research efforts concentrate on supporting such environments with SLA-aware advance reservation management systems. Hence, the robustness of the management system against network failures is an important issue, especially since failures frequently occur in networks. Since accurate knowledge about the failure duration is unlikely available and estimations lead to considerably degraded performance, in this paper we present a novel load-based approach for dealing with link failures in advance reservation environments. The approach does not rely on prediction of the downtime, but instead reroutes flows only based on available information about the network.