There are two main approaches to providing network survivability in Internet Protocol (IP) backbones: protection and restoration. Large IP networks usually combine protection and restoration mechanisms at various layers of the protocol stack to minimize service disruption in the event of failures. Sprint has chosen an IP-based restoration approach for building a highly available tier 1 IP backbone. This article describes the design principles of Sprint Corp.'s network that makes IP-based restoration an effective and cost-efficient approach. The effectiveness of IP-based restoration is evaluated by analyzing network failure characteristics, and measuring disruptions in service availability during controlled failure experiments in the backbone. Current trends for improving the performance of IP-based restoration are also discussed. The article concludes that if restoration, coupled with adequate capacity provisioning and careful network design, is indeed effective in providing network survivability for the Sprint network.