# Anchor-Based Method for Inter-Domain Mobility Management in Software-Defined Networking
## 2 Related Work  
Several authors have explored SDN-based approaches for mobility management. [PERSON] et al. [10] utilizes routing headers to sustain communication without IP tunneling mechanisms. However, their work does not delve into route selection, leaving a significant gap that requires a central controller to manage the network, which incurs additional costs. [PERSON] et al. [11] proposed FastSplit. This mechanism reuses previous routes to reduce signaling load, whereas new routes remain nearly optimal. FastSplit uses path length and signaling overhead to determine new routes but does not consider real-time information. In [8], the authors introduced mobility management based on Mobile IP, capable of handling inter-domain transfers. However, this approach relies on Mobile IPv6 and its route optimization function, which is not universally supported by all MNs. In [12], an OpenFlow-compatible Mobile IPv6 proxy (OF-PMIPv6) is proposed, which separates the control path from the data path. Specifically, the mobility control function resides in the controller while data paths between the Mobile Access Gateway (MAG) and Local Mobility Anchor (LMA) are maintained as an IP data tunnel. The MAG and the LMA are key components of the PMIPv6 (Proxy Mobile IPv6) protocol, designed to manage node mobility in IP networks. The MAG, located at the network edge, detects mobile node movements and establishes tunnels to the LMA, which is responsible for mobility anchoring and centralized traffic routing. The LMA maintains a database of active sessions and ensures communication continuity during handovers when nodes change their point of access. This collaboration ensures that nodes retain the same IP address while moving, providing seamless connectivity. However, this architecture can be limited by increased latency and potential failures at the LMA level. In [13], an S-DMM (Software-Defined Mobility Management) scheme was introduced based on the SDN architecture. S-DMM removes mobility logic from access routers, providing flow-based mobility support. S-DMM achieves a transfer performance similar to existing DMM but simplifies mobility management. In [14], the authors propose an OpenFlow-based Mobile IPv6 proxy (OPMIPv6) utilizing the OpenFlow architecture advantages. In OPMIPv6, LMA functions reside in an SDN controller, whereas the MAG function is implemented in an access switch or the controller. It alleviates IP-in-IP tunneling overhead by utilizing OpenFlow flow-table-based routing. In [15], an SDN-based DMM solution (SDN-DMM) was proposed. In SDN-DMM, mobility control was implemented as an application within the controller, leveraging the benefits of the SDN architecture. Lastly, Ref. [16] introduces a distributed IP mobility management scheme by adopting SDN technology. This scheme uses a flat mobile network architecture that eliminates a single point of failure. A flat mobile network architecture is a network design where no centralized hierarchy exists. In this type of network, entities responsible for management functions (such as access points, routers, or controllers) communicate directly with each other without relying on a single central point of control or routing. Furthermore, it utilizes multiple controllers to synchronize distributed mobility management mechanisms and alleviate the load on a centralized controller. The aforementioned SDN solutions can facilitate mobility management by leveraging SDN advantages. In [17], a PMIPv6-based solution, SDN introduces additional control signaling into OF-PMIPv6. The reactive and proactive transfer schemes of this solution enable improvements in transfer latency and packet loss compared to standard PMIPv6. In [18], a NO-PMIPv6 method was proposed, reducing the mobile support delay during inter-domain movement. This method draws inspiration from the strategic positioning of edge nodes and the PMIPv6 protocol to anticipate the mobile's next destination.