# Guidelines towards Information-Driven Mobility Management
## 3 Mobility Management Functional Aspects  
Mobility management is a relevant network function in today's Internet, and yet it is still one of the most challenging. The purpose of mobility management is to provide support for active communication in a way that allows services to be active with the least interruption, while users are on the move. For that purpose, mobility management handles three main processes: (i) location management; (ii) handover management; and (iii) multi-homing. _Location management_ has as a main purpose allowing data to flow adequately between source and destinations, independently of the whereabouts of the involved devices. Location management is supported by binding mechanisms that support the mapping between mobile nodes to specific identifiers, before, during, and after a move occurs. _Handover management_ concerns being able to identify new points of attachment for mobile nodes, and to allow data and signalling to flow to the new whereabouts of devices, while they are moving. From an end-user perspective, _Multi-homing_ concerns support for a device to use simultaneously its multiple interfaces, in order to increase performance and/or reliability of data transmission. From a network perspective, multi-homing concerns supporting one or multiple services, via two or more distinct network regions (or segments), towards consumers. In a pursuit to support these three processes, IP-based mobility management solutions share three main functional entities: (i) Mobile Nodes; (ii) Correspondent Nodes; and (iii) Mobility Anchor Points. The placement of these functional entities is illustrated in Figure 1. Such entities can then be co-located with different devices, depending on the selected mobility management approach [11]. The _Mobile Node (MN)_ corresponds to a functional entity that is part of an end-user device. Today, it is often located in a portable, battery-constrained device which is wireless or cellular enabled. The MN is the mobile or static entity that triggers communication. The MN has an active communication towards peers over the Internet, known as the MN _Correspondent Nodes (CNs)_. The MN has one (or more) identifiers, e.g., IPv6 addresses such as occurs in _Mobile IPv6 (MIPv6)_ and its extensions; URIs for a mobility management solution such as the _Session Initiation Protocol (SIP)_; and a locator-id based identifier for a solution such as the _Host Initiation Protocol (HIP)_. The MN functional role resides both on the data and control plane. The CN represents an \"active partner\" of the MN. The CN as defined in IETF RFC4885 [12] is \"Any node that is communicating with one or more MNs. A CN could be either located within a fixed network or within a mobile network, and could be either fixed or mobile.\" Today, it is an entity residing in a mobile device and is the receiver of a communication process started by the MN. In ICN, the functional representation of MN vs. CN could be simplified by considering a single entity, as we further explain in Sections 4 and 5. The reason to still differentiate between these two functional entities relates with the evolution of the Internet: at first, mobility management approaches were developed to support service and session continuity for the consumer of that service. This was the MN. The signalling required to support handovers was devised having in mind that particular entity, and assuming that all other elements in the network would be static. Later, with the introduction of two-way real-time communication in mobile environments, the solutions developed integrated extensions to handle CN mobility, as well as to attempt to handle simultaneous mobility by all of the involved parties. The _Mobility Anchor point (MAP)_ is a functional control plane entity that may reside in a network element (e.g., in a router) or in an end-user element (e.g., end-user equipment and server).