This chapter focuses on basic concept and method of mobility management solutions at the network layer. Typical protocols such as Mobile IP (MIP), Dual Stack Mobile IP, and Proxy Mobile IP are introduced, as well as related key technologies. The support of IP flow mobility, network mobility solutions, and security mechanism related to mobility management at network layer are also briefly described.
OverviewAt early age of Internet, hosts (e.g., mainframe computers, desktop computers, printers) are connected to the network via Internet Protocol (IP) [1]-based wired links, e.g., via Ethernet, cable, and xDSL. Due to the development of wireless communication, more and more hosts (e.g., laptop, tablet) require communication during or after movement. Lots of protocols of different layers and solutions which support host mobility appeared. Network-layer mobility management technology based on IP protocol, is featured by its agnostic to the underlying access technologies. It is also transparent to the upper-layer protocols and applications, and has become the focus of mobility management research.The Internet is designed for fixed or wired networks, where each host is assigned one IP address or more IP addresses (e.g., router) via either static configurations or dynamic interaction with network (e.g., via Dynamic Host Configuration Protocol (DHCP) [2]). However, exactly what IP address could be assigned to a host is based on network topology, rather than based on host's identity. Actually, an IP address actually identifies a network attachment point or an interface to the network, rather than the host itself. The host has fixed network attachment point, and the corresponding IP address could be considered as this host's identity as well.If a host changes its network attachment point, it will be assigned a new IP address. Thus, ongoing communication based on IP would be interrupted due to the following reasons: (a) IP packets destined to the host's old IP address arrived at old Some solutions have been proposed to resolve these problems. One of them is to update new IP address with corresponding part as soon as possible. However, this solution does not hide host mobility to upper-layer protocols and applications. For example, all application that is based on Transmission Control Protocol (TCP) [3] that requires fixed IP address during the lifetime of the TCP connection could not guarantee service continuity. Another proposal is to deploy host-specific routing within whole IP network. In this solution, the IP address allocated by host's home network would keep unchanged even the host has moved to another network attachment point. All routers within the network update their routing table with this host address, that is, a host-specific routing entry is created within the whole network. The signaling cost for host-specific route is high for a host. Considering that more and more hosts need mobility support, this solution would introduce huge routing update signaling. That is, this solution has poor scalability and efficienc...