# ICN-Oriented Mobility Support Method for Dynamic Allocation of Mobile Data Flows
## 2 Related Work
### Mobility Support in IP Networks  
This paper focuses on mobility support solutions in the network layer. The Internet Engineering Task Force (IETF) has defined some IP mobility management protocols, which can roughly be described as host-based mobility management protocols and network-based mobility management protocols. Mobile IP (MIP) [1] and Mobile IPv6 (MIPv6) [2; 3] are typical host-based mobility management protocols. With MIPv6, when a mobile node (MN) changes its network during handover, it will register its new address with the Home Agent (HA). A bidirectional tunnel will then be established between the MN and HA to forward the data packet to the new location of the MN. The main disadvantage of MIP is that all data packets from the Communication Node (CN) to the MN must be passed through the HA, which leads to triangular routing. Mobile signaling and data need to be handled by the HA, which can easily lead to a single point of failure and single point of attack. In order to reduce the long delay in exchanging mobile signaling between the MN and HA, the IETF proposed and standardized Hierarchical Mobile IPv6 (HMIPv6) [4]. HMIPv6 establishes a local HA called the Mobility Anchor Point (MAP) and establishes a hierarchy of MAPs in the form of a tree. The local HA handles mobility when the MN moves within the local area. When the MN leaves the locally mapped domain, the parent MAP of the local HA provides mobility support. In this way, HMIPv6 reduces handover latency. However, the problem of path extension caused by using MAPs is still not resolved. [PERSON] et al. [5] proposed a distributed mobility management protocol based on MIPv6, which uses more anchors at the edge of the network to shorten the distance between MNs and anchors. Multiple anchors bring higher tunnel overheads and network complexity. If the MN continues to move, the selection of anchors remains rigid and fixed. Therefore, the problem of switching path extension caused by using anchors still exists. In host-based mobility management protocols, besides solutions using anchors, there are also solutions that directly separate the dual functions of IP addresses. Host Identity Protocol (HIP) [8] adds a new host identification layer between the transport layer and the network layer, uses the Host Identity Tag (HIT) to identify the mobile node, and only uses the IP address for routing purposes. HIP introduces a Rendezvous Server (RVS) to store the mapping relationship between the HIT and IP address. When the MN moves, it will send a location update message to the RVS and CN to inform them of the latest address being used for the MN. ILNP [9] divides the IPv6 address into two parts: the upper 64 bits as the locator and the lower 64 bits as the identifier. DNS maintains a mapping between identifiers and locators. After the MN handover is completed, the MN sends a message to update the DNS and CN mappings. These protocols essentially solve the dual semantics problem of IP addresses. However, such protocols are highly dependent on the host to handle mobile signaling safely, which will bring greater handover delay. Next, we discuss network-based mobility management protocols. Proxy Mobile IPv6 (PMIPv6) [6] introduces a Local Mobile Anchor (LMA) and a Mobile Access Gateway (MAG) to handle mobility instead of the host. When the MN changes its network, its movement is detected by the MAG belonging to the new network. The MAG belonging to the new network then sends the signaling message to the LMA. In turn, the LMA establishes a bidirectional tunnel with the MAG to forward packets. Compared with MIPv6, PMIPv6 provides better performance in terms of handover delay and signaling costs. Because PMIPv6 still uses fixed a LMA, it does not solve the problems caused by fixed anchors. [PERSON] et al. [7] proposed a partial distributed mobility management protocol based on PMIPv6 called D-PMIPV6. It separates the control layer and data layer of traditional anchors. The MAG still controls mobile signaling and the MN's location.