Network-layer mobility management

Network-layer mobility management refers to the ability of a mobile node to maintain the IP address while it moves. In traditional IP networks, IP addresses are employed at the same time as host identifiers and locators. The former means that transport protocols in a TCP/IP stack operate based on a combination of IP addresses and ports as the identities for a communication between two processes. The latter means that IP addresses are also used as an aggregatable system of addresses that help to route packets toward their destination. The impact of mobility across different IP domains is observed in Figure 1, where a mobile node has established a communication with an application server. Once the mobile node changes its IP address from MN IP1 to MN IP2, packets sent by the application server with destination IP address MN IP1 get lost in the network (i.e., IP address unreachable). In addition, the translation in the DNS system gets outdated due to the change of IP address of the mobile node; hence, if a communication is to be established from an external server to the mobile node, it will fail until the entry in the DNS system is updated. A network-layer mobility management protocol intends to keep the same IP address of the mobile node even when the mobile node changes the point of attachment when moving among different IP networks. Therefore, the change of IP network becomes transparent to active applications and transport protocols running on top of IP