Survey on network mobility support <s> I. Introduction <s> This document specifies Mobile IPv6, a protocol which allows nodes to ::: remain reachable while moving around in the IPv6 Internet. Each mobile ::: node is always identified by its home address, regardless of its ::: current point of attachment to the Internet. While situated away from ::: its home, a mobile node is also associated with a care-of address, ::: which provides information about the mobile node's current ::: location. IPv6 packets addressed to a mobile node's home address ::: are transparently routed to its care-of address. The protocol enables ::: IPv6 nodes to cache the binding of a mobile node's home address ::: with its care-of address, and to then send any packets destined for ::: the mobile node directly to it at this care-of address. To support ::: this operation, Mobile IPv6 defines a new IPv6 protocol and a new ::: destination option. All IPv6 nodes, whether mobile or stationary, can ::: communicate with mobile nodes. This document obsoletes RFC 3775. <s> BIB001 </s> Survey on network mobility support <s> I. Introduction <s> This document specifies protocol enhancements that allow transparent routing of IP datagrams to mobile nodes in the Internet. Each mobile node is always identified by its home address, regardless of its current point of attachment to the Internet. While situated away from its home, a mobile node is also associated with a care-of address, which provides information about its current point of attachment to the Internet. The protocol provides for registering the care-of address with a home agent. The home agent sends datagrams destined for the mobile node through a tunnel to the care- of address. After arriving at the end of the tunnel, each datagram is then delivered to the mobile node. <s> BIB002
As wireless networking products and services proliferate, users expect to be connected to the Internet from "anywhere" at "anytime". It has moreover become the norm for a person to own more than one mobile device, say a mobile phone, a laptop and a PDA. Each of these devices could likely have multiple network interfaces that enable them to interconnect with each other as well as with other networks. These devices moving with the user together constitute a Personal Area Network or PAN, and are an example of a smallscale mobile network. Access networks deployed on public transportations such as ships, trains, buses and aircrafts are examples of mobile networks at a larger scale. The IETF has in recent years developed protocols such as Mobile IPv4 (MIP) BIB002 and Mobile IPv6 (MIPv6) BIB001 for supporting seamless connectivity to mobile hosts. These host mobility support protocols however, get triggered upon link layer handoffs, which may not be seen by all nodes moving as part of a mobile network. Moreover, not all nodes in a large mobile network may be sophisticated enough to run such mobility support protocols. These deficiencies have been realized by the IETF, and a working group called NEMO (NEtwork MObility) [3] has been commissioned to extend the existing protocols or develop new ones to support network mobility in an IPv6 network. In this paper, we survey the state-of-the-art in mechanisms for supporting network mobility. We first motivate the problem, identify its characteristics, and illustrate why existing solutions do not suffice. We next identify the solution design requirements, and then review some of the solutions proposed in the literature. The remainder of this paper is structured as follows. Section II presents typical network mobility scenarios and identifies the most desirable architecture. Section III presents previous work in relation to the Mobile Router architecture on an IPv4 and IPv6 network mobility setting. Section IV identifies some characteristics of mobile networks and the requirements they impose on the associated design. The IETF's proposed solution is reviewed in Section V. Section VI presents some open research issues, and particular issues related to route optimization are discussed in Section VII. Section VIII lists some of the recent projects on network mobility, and Section IX concludes the paper.