The Survivable Network Design Library (SNDlib) is a data library for fixed telecommunication network design, available online at http://sndlib.zib.de. Version 1.0 contains data for 22 networks, combined with planning parameters, resulting in 830 network planning problem instances. The library provides mathematical models for each planning problem, describes data concepts, and includes statistical information and data origin details. SNDlib aims to become a standard for testing and demonstrating the effectiveness of new optimization models and algorithms. It includes benchmark instances, solutions, dual bounds, references to publications, conferences, and a mailing list. The library is structured to allow users to submit solutions, dual bounds, or references to new papers. SNDlib data is organized into network and model parts, with network descriptions including nodes, links, demands, and capacities, and model parts specifying design parameters. The library supports various network design problems, including survivability concepts like 1+1 protection, shared path protection, and unrestricted flow reconfiguration. The SNDlib provides a mathematical reference model for network design problems, including constraints, variables, and objective functions. The library includes 22 network instances with different topologies and characteristics, covering a range from small to large problems with varying densities, cost structures, and routing constraints. SNDlib is intended to provide realistic network planning data for the network design community, enabling comparison of mathematical models and optimization algorithms. The library also serves as a platform for sharing other information required by the community, including bibliography entries, conference lists, relevant journals, and a mailing list. Users are encouraged to contribute to SNDlib by submitting solutions, dual bounds, new test instances, references, and tools. The SNDlib is supported by a team of contributors who have helped build the library by providing network instances, problem solutions, bibliography information, and programming work.The Survivable Network Design Library (SNDlib) is a data library for fixed telecommunication network design, available online at http://sndlib.zib.de. Version 1.0 contains data for 22 networks, combined with planning parameters, resulting in 830 network planning problem instances. The library provides mathematical models for each planning problem, describes data concepts, and includes statistical information and data origin details. SNDlib aims to become a standard for testing and demonstrating the effectiveness of new optimization models and algorithms. It includes benchmark instances, solutions, dual bounds, references to publications, conferences, and a mailing list. The library is structured to allow users to submit solutions, dual bounds, or references to new papers. SNDlib data is organized into network and model parts, with network descriptions including nodes, links, demands, and capacities, and model parts specifying design parameters. The library supports various network design problems, including survivability concepts like 1+1 protection, shared path protection, and unrestricted flow reconfiguration. The SNDlib provides a mathematical reference model for network design problems, including constraints, variables, and objective functions. The library includes 22 network instances with different topologies and characteristics, covering a range from small to large problems with varying densities, cost structures, and routing constraints. SNDlib is intended to provide realistic network planning data for the network design community, enabling comparison of mathematical models and optimization algorithms. The library also serves as a platform for sharing other information required by the community, including bibliography entries, conference lists, relevant journals, and a mailing list. Users are encouraged to contribute to SNDlib by submitting solutions, dual bounds, new test instances, references, and tools. The SNDlib is supported by a team of contributors who have helped build the library by providing network instances, problem solutions, bibliography information, and programming work.