e to reduce handoff delay and disruption effects. Micro-mobility (intradomain © 2009 by Taylor & Francis Group, LLC SIP Security and Quality of Service Performance motion det ection overlap packet FIGURE 22.8 Handoff delay and packet loss instances. mobility) protocols aim to handle local movement (e.g., within a domain) of mobile hosts without interaction with the mobile IP enabled Internet [9]. A macro-mobility (or interdomain mobility) protocol based on mobile IP man- ages mobility between domains [9]. Kwon et al. [4] found that the disruption for handoff of the mobile IP approach is smaller than that of the SIP approach in most situations, however, SIP shows shorter disruption when the mobile node (MN) and correspondent node (CN) are close because the need for hand- off is reduced in such situations. While the SIP-based approach offers several advantages over a corresponding MIP-based solution for typical UDP-based VoIP streams, it continues to suffer from several drawbacks. These include the absence of a mobility management for long-term TCP connection. Second, it can cause call disruption if the new SIP session is not created completely while the mobile terminal is in the overlapped area. As opposed to a mobile node using mobile IP, a mobile node using SIP-mobility always needs to acquire an IP address via DHCP which can be a major part of the overall handoff delay. Several delays or disruption factors [10] affect the handoff delay and packet loss over wireless networks (Figure 22.8). These are: 1. TmTOc: The one-way delay from the mobile node to correspondent node. 2. ThTOn: The delay in sending a message between the new foreign agent and HA. 3. TDHCP: IP address renewal time through DHCP 4. Hmax is the maximum time for seamless handoff. It is the time difference between when motion is detected and the time when the node escapes from the old cell. 5. Toverlap is the time over which the mobile node is within the overlap area of two adjacent cells. Lpacket: Packet loss time during handoff process. This is th