Assuming you're referring to packet switched networks;
Resource guarantees. You'll need management protocols to reserve resources (switching and bandwidth) to specific flows. In a circuit switched network these are inherent part of the network.
Another is timing. You'll need specific (SyncE) hardware to keep network node clocks in sync. Think of mobile networking where RF functions are to be synchronized over the network.
Another is jitter. Usually more severe than in circuit switched networks. To be managed through jitter buffers.