As the number of network service provider’s increases so the numbers of handoffs are ncreases to avail the best quality of services within affordable cost. In such scenarios fast and secure handoff is obligatory but diversification always creates worries of intruders and latency due to heterogeneous architectures with multiple access points. And elongated latency may go ahead to jitter, ping pong effect, triangular routing and packet loss like issues. Neither the reactive nor the proactive protocols alone for vertical hand off addresses the problem of latency efficiently due to their onboard calculation during peak time of handoff. Ensuring security in such frequent vertical handover without interrupted and delayed services is challengeable but desirable as well. Here i proposed a hybrid model for vertical handoff dividing the standard IEEE 802.11 hand off phases in reactive and proactive manner. Initially executing riggering, discovery and authentication phases in proactive... Это и многое другое вы найдете в книге Networks Security and Communication (Mohammad Faisal)