off disruption time also increases with the delay separation between the CN and mobile node and their intra- domain handoff disruption times remain flat with MIP always out perform- ing SIP. Over low bandwidth wireless links, the disruption times resulting from inter and intradomain handoffs increase linearly as the wireless link delay increases and the intradomain disruptions are always smaller (MIP smaller then SIP). This is shown in Figure 22.10 from Kwon et al. [4]. 22.2.3.1.4 Disruption time with shadow registration When shadow registration is included in the operation of MIP and SIP, the disruption times change. Since AAA resolution for the mobile node can be performed within the foreign network (AAAF), the disruption time for the MIP case is: (a) a function of the router solicitation and advertisement message exchange time (2ts), the registration message time from the mobile node to the © 2009 by Taylor & Francis Group, LLC SIP Handbook: Services, Technologies, and Security MIP intra MIP inter SIP intra SIP inter Wireless link delay (ms) FIGURE 22.10 Disruption time as a function of wireless link delay for MIP and SIP. (From Kwon, T. T., M. Gerla, S. K. Das, and S. Das. 2002. Mobility management for VoIP services: Mobile IP VS SIP. IEEE Wireless Communications 9: 66-75.) (b) the reply time to the mobile node (2tf ts) and (c) the route optimization signaling flow time (th - ts) + tmc Therefore the total disruption time is given by the sum: MIP inter_sdw = 2ts (2tf-ts)+(th -ts) + tno the + tmc =2tf+th+tnotthc+tmc (22.16) In the case of SIP, the REGISTER message is handled locally also in the foreign network DHCP acquisition and the ARP consumes the time (4ts + tARP). Furthermore, the AAA resolution and REGISTER is performed in the foreign network with time (2tf). This is followed by the mobile node re- inviting the CN by sending the re-INVITE message with time (2tmc). The total disruption time is therefore given by the expression: tSIP_inter_sdw = 4ts + tarp + 2tf 2tmc (22.17) Note that the disruption time n