Link characterization is essential for verifying that fiber infrastructure will support new equipment being placed into service when upgrading networks from 2.5 Gbit/s to 10 Gbit/s and even to 40 Gbit/s. Although these powerful systems can take network performance to the next level, they require proper installation, tuning and maintenance. Network service providers need to perform several tests to properly characterize their links when planning to increase the capacity of their network.