# Integrating IP Mobility Management Protocols and MANET: A Survey
## 4 IP Mobility Management in MANET and Comparative Summary
### Proactive Gateway Discovery-Based Mobility Management Solutions  
Proposals under this category share the common use of an agent advertisement message to disseminate gateway information and presence proactively. Similar to Mobile IP, these systems configure foreign agents or mobile gateways to broadcast gateway advertisement message periodically. Table 1 shows a summary of the proactive gateway discovery-based mobility solutions. It highlights the characteristics, functionalities, design, and evaluation of these systems. An overview of 11 different proposals under this category is provided below. Performance evaluation of mobile IP on mobile ad hoc networks using NS2[35] evaluates the performance of MIPv4 over different MANET routing categories. They combine MIPv4 with three MANET routing protocols; AODV, AOMDV, and DSDV to evaluate mobility management for MANET mobile nodes. No modifications were introduced to the original MIPv4. Proposed architectures were evaluated using the NS2 Network simulator and the paper suggested that plain MIPv4 works better when used with the reactive MANET routing protocol (AODV and AOMDV). Performance evaluation of mobile IP with DSDV routing protocol using NS2[36] similarly evaluated the performance of MIPv4 over a DSDV MANET routing protocol. The combination was evaluated using NS2 without any modification of the MIPv4. The paper concluded that the overall performance of the MIPv4, as a mobility management solution for MANET, decreases as the size of MANET increases (only 25 mobile nodes were used). An efficient integrated routing protocol for interconnecting mobile ad hoc networks and the internet[37; 38] proposed a system that incorporate MIPv4 and an extended version of DSDV named Eff-DSDV [39] (Figure 8). The proposed system uses the proactive nature of the DSDV to serve as registration with the Mobile IP proxy agent. It uses the routing update messages of DSDV to inform participating MANET nodes of the existence of a Mobile IP agent. After that, a MANET node will be able to send its registration request to the agent, which in turn forwards the registration to the home agent. The home agent then replies to the Mobile IP proxy agent, which forwards the reply to the MANET node. This system is proposed to work using only one gateway. This may be a drawback of the system since a single gateway means a single potential point of failure. **MIPAD**[40] is a system that modifies Mobile IPv6 to provide for efficient mobility management when an ad hoc node moves from one subnet to another. It aims to reduce the signaling overhead, handover latency, and packet loss rate when using Mobile IP over an AODV MANET. It splits the network into various service regions depending on the coverage of the access routers. When a mobile node moves into an overlapping area, it decides whether to stay connected to the previous foreign agent or to register with the new one. The decision depends on the calculation of proposed equations that include several parameters; registration cost with the foreign agent, registration cost with the home agent, the hop count to the home and foreign agent, average residence time at a subnet, traffic load, and the packet arrival rate. If the calculated value is less than a predefined threshold, the mobile node would stay connected to the current agent and no handover would take place. The paper does not explain how these metric parameters can be exchanged, however, and the evaluation scenario only has one mobile node, which did not offer a suitable environment to demonstrate all of the mentioned metrics. _Thorough protocol extensions for integrating DSR-based mobile ad hoc networks with the internet_[41] proposed a system that extends the DSR MANET routing protocol to connect MANET to the internet using Mobile IP. The proposed architecture (Figure 9) consists of multiple gateways that advertise their existence periodically (proactive) or on demand (reactive). A gateway with its connected mobile nodes (directly or through multi hops connection) constitutes a mobility domain.