I discuss synchronization in delay-coupled networks of identical units. In general the stability of synchronization depends in a complicated way on the coupling topology. I show that for large coupling delay the problem is drastically simplified. The master stability function used to determine the stability of the synchronous solutions has a universal structure in this limit, which allows to classify networks with respect to their synchronization properties. This classification is independent of the type of nodes and the type of coupling function. Further, I discuss the concept of weak and strong chaos, which has important consequences for chaos synchronization in the network. Finally, I show how these general results can be applied to analyze network motifs of optically coupled lasers.