# 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
A mobility agent that resides in between the two networks is set to advertise information using two different lifetimes and two different values for coverage zone. The first type of advertisement is an Agent Advertisement message with Short beacon Interval AASI. AASI is identical to the agent advertainment message of the Mobile IP with the scope set to one hop. The second type is an agent advertisement message with long beacon interval AALI. The AALI is similar to the Mobile IP advertisement except for the lifetime, which was suggested by the proposed system to be 300 s and 200 hops, respectively. The proposed system consists of three main entities: Foreign agents, inner nodes, and outer nodes. A foreign agent takes the role of routing between the two networks and broadcasts AASI periodically to its one hop neighbor. It also floods the whole network with AALI. Nodes inside the one hop scope of the foreign agent are considered inner nodes, and nodes outside the one hop scope of the foreign agent are known as the outer nodes. Upon receiving a mobility advertisement, a mobile node is required to register with the mobility agent using the traditional Mobile IP registration procedure. Despite the fact that the system was proposed to reduce integration routing overhead, the approach of using two types of gateway advertisement would increase the overheads. [PERSON][45] proposed a generic solution for mobility management using Hierarchical Mobile IPv6, which could work with reactive or proactive MANET. It divides the network into parts, based on the HMIP. Each part consists of multiple access routers (AR) that are managed by a Mobility Anchor Point (MAP). A mobile node is required to register with two of the existing ARs and obtains a Local On-Link Care-of-Address (LCaA) for each AR. The discovery of AR can be done via a broadcasting gateway advertisement message by the ARs, or by explicitly asking the ARs to send the gateway advertisement messages. Upon receiving gateway information, a mobile node chooses the two best AR based on the hop number from the same MAP, then sends a registration packet to all available ARs notifying them to update their records. ARs in turn forward the registration packet to their MAP to update its own record as well. Once a mobile node finds a new AR in the same MAP that is two hops closer than one of its ARs, it starts the handoff by sending a new registration packet. When a mobile node finds two ARs that are two hops closer than its current ARs, and which belong to different MAP, it starts a new registration procedure. The system is deployed over DSDV and AODV. The proposed system is quite generic, however, and floods the mobility management traffic over the exiting MANET routing traffic. This would consequently result in higher overheads. Mobile IP enriched wireless local area network architecture (MEWLANA)[46] presented a mobile-enriched wireless local area network architecture with two versions to extend Mobile IP functionality to MANET. These are MEWLANA-TD, which is based on DSDV protocol, and MEWLANA-RD, which uses the proposed table-based bidirectional routing (TBBR). The proposed architecture consists of three domains. The first domain is the internet cloud that contains home agents and corresponding nodes. The second is the foreign agent domain, which lies between the internet  
Figure 10: An OLSR-IP access network interconnected to a Mobile-IP [43]. and MANET domains, and consists of foreign agents and mobile nodes one hop away. A foreign agent is not part of MANET and therefore does not operate MANET routing protocol. The third domain is the MANET network. Foreign agents broadcast a periodic agent advertisement, as in Mobile IP, that contains a care of address and source address and hop counts. A mobile node, which is in the foreign agent domain, alters the source address of the received agent advertisement message to itself and rebroadcasts it, so other mobile nodes in the MANET domain can use this node as an access point.