Quantum optical networks will enable distribution of quantum entanglement at long distances, with applications including interconnects between future quantum computers and secure quantum communications. In this talk I will give an overview of the state of the art in solid state quantum networks based on single optically addressable spins, followed by a more in-depth discussion of implementations based on single rare-earth ions. I will focus on ytterbium 171 in yttrium orthovanadate which exhibits long spin coherence times and stable optical transitions. The nearby vanadium nuclear spins can be utilized as nuclear spin wave quantum memory registers. The advantages and disadvantages compared to other systems will be discussed.