# A Method for 5G-ICN Seamless Mobility Support Based on Router Buffered Data
## 5 Performance Evaluation
### Experiment Setup  
The experimental platform includes Mininet, OpenvSwitch and Ryu [43] controllers. This section uses Mininet to create the network topology. Considering that there may be multiple handover paths after UE mobility handover, this article simulates a multi-path network topology, as shown in Figure 3. We use OpenvSwitch to simulate routers, UPF, and base stations to implement data forwarding. Each UPF is independently connected to an access router. Set buffers on the access router and base station. Ryu is a controller that can connect to OpenvSwitch through the OpenFlow1.3 protocol. In order to simulate mobility in Mininet, we modified its code to allow mobile nodes to handover from one base station to another. To enable routing in a multipath network topology, we employ a routing protocol on the controller, utilizing the Dijkstra algorithm with bandwidth as the weighting factor.  
Table 2 shows the parameter settings of our simulation experiments. We consider that the rate of the Content Server sending mobile data flows is \(R\), the average packet size is \(P\), and the number of mobile data flows is \(N\). The mobile buffer size on the base station or access router is \(B\). The experiment uses two types of mobile data flows, namely real-time data flows and non-real-time data flows. The real-time data flows priority is 0.95 and the non-real-time data flows priority is 0.05. The period of mobile buffer update threshold is \(\Delta t\). The time from when the UE disconnects from the source base station to when it connects to the target base station is \(T_{ST}\), the latency of the Name Resolution System (NRS) responding to the access router's query is \(T_{RA}\), wired link delay is \(T_{wired}\) and the wireless link delay is \(T_{wireless}\). The delays of all wired/wireless links in the simulated network topology are the same. During the simulation, the Content Server continues to send mobile data flows to the UE. The size of the mobile buffer and the rate of sending data packets can be adjusted with different simulations. The total experimental simulation time is 2 s. After one second, the experiment simulates UE movement. In each simulation round, we compute the mean value of the measured performance metrics.  
Figure 3: Simulation topology.  
Our mobile scenario pays special attention to whether the UE switches across UPFs, that is, whether the UE changes its network address. To evaluate the performance of the seamless mobility method on average packet delay, weighted average packet loss rate, and average handover delay, we simulated two scenarios. Scenario 1 is a cross-UPF handover scenario, simulating a UE handover from BS2 to BS3. Scenario 2 is a non-cross-UPF handover scenario, simulating a UE handover from BS2 to BS1. Corresponding to the two different scenarios, we set \(T_{ST}\) to 100 ms and 80 ms, respectively. For both scenarios, we use the following simulation settings. We consider that the Content Server sends 10 data flows to the UE, including 5 real-time data flows and 5 non-real-time data flows. Initially, the rates of both real-time and non-real-time data flows are set to 10 Mbit/s. At 1.05 s after the simulation starts, the rate of all real-time data flows is reduced to 5 Mbit/s, and the rate of all non-real-time data flows is increased to 15 Mbit/s. We adjust the size of the mobile buffer from 100 packets to 900 packets. Other parameter settings are shown in Table 2.  
When evaluating the performance of the seamless mobility support method in terms of network overhead, we also simulated the two handover scenarios. For both scenarios, we use the following simulation settings. We simulated the Content Server sending multiple real-time data flows to the UE, fixed the packet sending rate of each flow to 10 Mbit/s and adjusted the number of data flows from 1 to 10. We observe the size of the mobile buffer occupied by all data flows before receiving a release notification.