The next generation broadband wireless networks support real-time applications like VOIP and video streaming. They allow users to roam over the network seamlessly and securely. Current design incurs lengthy delay between breaking of previous connection and making of next connection. Cross layer design and cross function optimization are required to improve the handover latency of broadband wireless networks. We discuss the fast handover algorithms that combine the mechanisms in the MAC layer with that of the IP layer. Fast key exchange and fast authentication procedures are introduced to reduce authentication time during network re-entry. The effects of latency reduction by fast authentication are compared with results of other solutions. We also discuss standard activity for media independent handover in heterogeneous networks.