This work considers how network slicing can use the network architecture Cloud-Radio Access Network (C-RAN) as an enabler for the required prerequisite network virtualization. Specifically this work looks at a segment of the C-RAN architecture called the fronthaul network. The fronthaul network required for network slicing needs to be able to dynamically assign capacity where it is needed. Deploying a fronthaul network faces a trade-off between fronthaul bitrate, flexibility, and complexity of the local equipment close to the user. This work relates the challenges currently faced in C-RAN research to the network requirements in network slicing. It also shows how using a packet-switched fronthaul for network slicing will bring great advantages and enable the use of different functional splits, while the price to pay is a minor decrease in fronthaul length due to latency constraints.