Distributed mobility management for future 5G networks: overview and analysis of existing approaches <s> DISTRIBUTED MOBILITY MANAGEMENT <s> In this article, we introduce distributed mobility management (DMM) - a new architectural paradigm for evolving mobile IP networks. We discuss the technology trends that are driving a move toward DMM and what the relevant standards development organizations (IETF and 3GPP) are doing to address these new needs. We conclude with a discussion of how 3GPP's evolved packet core can evolve toward a DMM-based architecture. <s> BIB001 </s> Distributed mobility management for future 5G networks: overview and analysis of existing approaches <s> DISTRIBUTED MOBILITY MANAGEMENT <s> This document presents a method for applications to influence the IPv6 ::: source selection algorithm used by the IP stack in a host. To do so, ::: IPv6 prefixes are associated with meta-data when configured by the ::: network. This meta-data allows the network to describe the purpose and ::: properties of the prefix enabling applications to make intelligent ::: decision when selecting a prefix. <s> BIB002 </s> Distributed mobility management for future 5G networks: overview and analysis of existing approaches <s> DISTRIBUTED MOBILITY MANAGEMENT <s> This document defines the requirements for Distributed Mobility ::: Management (DMM) at the network layer. The hierarchical structure in ::: traditional wireless networks has led primarily to centrally deployed ::: mobility anchors. As some wireless networks are evolving away from the ::: hierarchical structure, it can be useful to have a distributed model ::: for mobility management in which traffic does not need to traverse ::: centrally deployed mobility anchors far from the optimal route. The ::: motivation and the problems addressed by each requirement are also ::: described. <s> BIB003 </s> Distributed mobility management for future 5G networks: overview and analysis of existing approaches <s> DISTRIBUTED MOBILITY MANAGEMENT <s> This document analyzes deployment practices of existing IP mobility ::: protocols in a distributed mobility management environment. It then ::: identifies existing limitations when compared to the requirements ::: defined for a distributed mobility management solution. <s> BIB004
The deployment of extremely dense radio networks addresses the need to expand the network capacity, offering an increased bandwidth per user per unit of area. The cellular pico and femto cells, in conjunction with the new advances in the IEEE 802.11 family, like the .11n and .11ac amendments, are speeding up the development in this direction. Within this context, the current mobile architecture's centralized model poses some scalability issues due to traffic and signaling handling. For instance, in the Evolved Packet System (EPS) architecture, traffic generated in the radio access network (RAN) is conveyed by intermediate nodes called serving gateways (S-GWs) to the packet data network gateway (P-GW) by means of tunneling. The P-GW hence aggregates the traffic from several edge networks and acts as a gateway between the operator's network and external IP networks. While the deployment of extremely dense wireless networks tackles the expected traffic growth in the access part, a solution is also necessary for the core. In this sense, a flatter mobile network is best suited, as it would permit traffic to be routed without traversing core links unless necessary. Moreover, future 5G networks will simultaneously serve traffic from multiple devices with disparate requirements, as, for example, the IoT is expected to increase its footprint in the coming years. This fact requires more flexible network architectures capable of coping with multiple flows with different requirements, and dynamically adapting to the current demands. The Third Generation Partnership Project (3GPP) 1 has already started developing solutions for the EPS to avoid tying IP connections to core gateways, like the Local IP Access and Selected IP Traffic Offload (LIPA-SIPTO) techniques  and LIPA Mobility and SIPTO at the Local Network (LIMONET)  . Consequently, IP networks appear closer to user terminals, since the complex operator's backhaul and core infrastructure might be bypassed. Very dense wireless networks could take advantage of this scenario, as they can be deployed in campuses, malls, transportation systems, and so on, which can benefit from having a locally available connection to Internet services (called a local breakout point) so that traffic generated locally is not forced to pass through the core network. In addition, users should join and leave any of these networks without experiencing any service interruptions, enjoying transparent mobility support for those applications that require so. The DMM paradigm embraces the concepts expressed above, aiming at designing a flat mobile architecture that enables enhanced access to IP services and built-in support for mobility and heterogeneous radio access technologies BIB003 BIB004 BIB001 . The DMM framework envisions an all-IP infrastructure where users' data flows are routed through the optimal path, exploiting multiple anchor points and deployment of IP services closer to the users. Note that this framework envisions supporting mobility across heterogeneous networks, without requiring complex dedicated support from MNs. In addition, a wise assignment of IP addresses to MNs according to the available services for each user provides a mobile operator with the flexibility to handle users' data traffic according to an extended set of policies, such as whether IP flows should be anchored locally (e.g., for short-term sessions) or to a centralized node (for long sessions). This feature -which is very attractive for future 5G deployments, as previously discussed -is known as prefix coloring BIB002 , and consists of attributing some meta-data to the assigned prefixes so that they can be used to access particular services, differentiated for the geographical location or by other means depending on the operator's policy.